PHOTOELECTRIC CONVERSION DEVICE AND METHOD FOR MANUFACTURING THE SAME 5 TECHNICAL FIELD The present invention relates to a photoelectric conversion device having high conversion efficiency, and a method for manufacturing the same. 10 BACKGROUND ART From the viewpoint of effective utilization of resources or protection against environmental contamination, a solar cell for directly converting sunlight into electrical energy has received much 15 attention in recent years and various researches and developments of the solar cell are under progress. Most of the solar cells use crystalline silicon or amorphous silicon as a. material for photoelectric conversion. The photoelectric conversion efficiency to 20 represent the property of converting light energy of sunlight into electrical energy is higher in a crystalline silicon solar cell compared to an amorphous silicon solar cell. As such, the crystalline silicon solar cell has been conventionally used more often as a 25 solar cell. However, since the crystalline silicon solar cell required lots of energy and time for growing silicon crystals, it has low productivity and high cost. As compared with a crystalline silicon solar cell, the amorphous silicon solar cell. is advantageous in that 30 it can absorb and use light with a. broader wavelength range, a substrate made of various raw materials can be selected, and a. cell with a large area can be easily prepared. Further, without need for crystallization, it can be produced at low cost with favorable productivity compared to a crystalline silicon solar cell. However, 5 the photoelectric conversion efficiency is lower than that of a crystalline silicon solar cell. In addition to a solar cell in which crystalline silicon or amorphous silicon is used, there is a dye sensitization solar cell which uses an electrode composed 10 of a porous metal oxide semiconductor loaded with a dye. As compared with a silicon solar cell, the dye sensitization solar. cell is advantageous in that the raw materials required for manufacturing the cell are less limited in terms of resources, and the cell can be 15 manufactured by a printing system or a flow production system, without need for a vacuum equipment and, hence, has low manufacturing cost and equipment cost. A common. dye sensitization solar cell includes a working electrode composed of a porous metal oxide 20 semiconductor layer formed on a surface of a transparent conductor layer and loaded with a dye and a counter electrode composed of a transparent or opaque conductor layer and/or a catalyst layer and has a configuration in which the working electrode and counter electrode are 25 arranged to face each other while an electrolyte layer is disposed between them. As a porous metal oxide semiconductor layer, titanium oxide is used. As a dye, a sensitizing dye like ruthenium complex is used. In addition, as an electrolyte layer, an electrolyte 30 containing iodine as a major component is used. As for the porous metal oxide semiconductor layer 2 in a dye sensitization solar cell, for example, a porous titanium oxide layer, dispersion paste of titanium oxide particles is generally prepared, coated on the surface of a transparent conductor layer, and dried followed by 5 calcination at 350°C to 450°C under the purpose of enhancing binding state among the particles and improving electron diffusion property (see, Patent. Document 1 to be described below, for example). As for the dye sensitization solar cell in which a. 10 resin (polymer) is used as a base, it has been tried to form a porous titanium oxide layer by calcination at a low temperature at :which. the resin (polymer) is not melt (see, Non-Patent Document. 1. to be described below, for example). In addition, with regard to a method of 15 producing a porous metal oxide semiconductor layer in a dye sensitization solar cell which uses a resin (polymer) as a base, a method of pressing a metal oxide particle layer is known as a method of preparing a porous metal oxide semiconductor layer (see, Non-Patent Document 2 and 20 Patent Document 2). In addition, a surface modification. method based on plasma treatment of a porous titanium dioxide layer is known (see, Patent Document 1 and Patent Document 3 to be described below, for example). 25 In addition, since amount of adsorbed water and amount of hydroxyl group on a surface of an oxide semiconductor can be calculated by measuring pressure change due to chemical species desorbed from the surface of an oxide semiconductor or amount change of desorbed 30 chemical species in accordance with increasing the temperature on a solid surface at constant rate and. 3 analyzing the adsorbed chemical. species, and also adsorption amount, adsorption state on the surface, or desorption process from the surface, it is established as a thermal desorption analysis (see, Non-Patent Document 3 5 to be described below, for example). CITATION LIST PATENT DOCUMENTS Patent Document 1: Japanese Patent Application Laid-Open 10 No. 2006-310134 (paragraphs 0017 to 0028) Patent Document 2: WO 00/72373 (claim 1) Patent Document 3: Japanese Patent Application Laid-Open No, 2004-247104 (paragraphs 0015 to 0019) NON-PATENT DOCUMENTS 15 Non-Patent Document 1: UCHIDA Satoshi, SEGAWA Hiroshi, "Film type dye sensitization solar cell as flexible device", Functional Materials, Vol. 29, No. 10, 29-35 (20009) (3. Stability of titanium oxide electrode used for film type dye sensitization solar cell, 4. Microwave 20 calcination technique for titanium oxide electrode). Non-Patent Document 20 H. Lindstron of al., "A New Method for Manufacturing Nanostructured Electrodes on Plastic Substrates", Nano lett., Vol. 1, No. 2, 97-100 (2001)(E.xperimental Section, Result and Discussion) 25 Non-Patent Document 3: HIRASHITA Norio, UCHIYAMA, Taizou, "Quantitative analysis of gas released from materials for semiconductor integrated circuit measured by thermal gas desorption analysis", Analytical Chemistry, 43, 757 (1994). 30 SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION According to Patent Document 1, a calcination process at a high temperature of from 350°C to 450°C is adopted under the purpose of enhancing binding state 5 among the particles in a porous metal oxide semiconductor layer and improving electron diffusion property. Thus, a usable base is limited to those made of materials with high heat resistance, for example, glass, and therefore production cost like raw material cost for a base used 10 for a dye sensitization solar cell or cost of energy consumed for manufacturing the solar cell is quite high. In addition, according to Non-Patent Document 1, for a dye sensitization solar cell in which a resin (polymer) is used as a base, it is tried to form a porous 15 titanium oxide layer by calcination at a low temperature at which the resin (polymer) is not melt. However, the conversion efficiency is low, the porous titanium oxide layer formed by the low temperature calcination is easily broken, and durability of a cell in which the porous 20 titanium oxide layer is used is poor. There are also problems in that the calcination time is relatively long for the low temperature calcination and thus it is disadvantageous as a process for large scale production. In addition, according to a method of producing a 25 porous metal oxide semiconductor layer by pressing the metal oxide particle layer as described in Non-Patent Document 2 and Patent Document 2, high pressure like several hundred kgf/cm2 needs to be used just for pressure treatment, Thus, a hydraulic device with high 30 pressure is required. Further, from the viewpoint that the roll used for delivery of pressure in a continuous 5 production device like roll to roll is easily worn out or broken and the processing speed is slow, it is an inappropriate method for continuous production. For forming a porous metal oxide semiconductor 5 layer to constitute a dye sensitization solar cell, a calcination treatment at a high temperature is required. A base and a transparent electrode consisting of a transparent conductor layer, which are used for the cell, are also required to have heat resistance. In this 10 regard, since a common transparent electrode like ITO has no heat resistance, it is necessary to use fluorine-doped tin oxide, which is a transparent electrode with particularly excellent heat :resistance. However, the fluorine-doped tin oxide has poor conductivity and is 15 inappropriate for use in a solar cell or the like which requires a large area. Further, to enhance the photoelectric conversion efficiency of a dye sensitization solar cell, it is important to improve characteristics of a porous metal 20 oxide semiconductor layer. Accordingly, improvements like increasing the dye adsorption amount on a porous metal oxide semiconductor layer, inhibiting reverse electron process from a porous metal oxide semiconductor layer, and increasing the interparticle or interparticle 25 electron diffusion property of the oxide particles of a porous metal oxide semiconductor layer are required. Further, although Patent Document 1 discloses that the dye adsorption amount is increased by increasing a concentration of a hydroxyl group on the surface by 30 plasma treatment of a. titanium dioxide layer and Patent Document 3 discloses that. the conversion efficiency is 6 improved by plasma treatment of a titanium dioxide layer, no description is given with regard to the concentration of hydroxyl group on the surface and a concentration of adsorbed water on a titanium dioxide layer. 5 SOLUTIONS TO PROBLEMS The present invention is devised to solve the problems described above, and an object of the invention is to provide a photoelectric conversion device having 10 high conversion efficiency and a method for manufacturing the device. Specifically, the invention is directed to a photoelectric conversion. device having a working electrode on which a porous metal oxide semiconductor 15 layer is formed to support a dye (for example, the transparent electrode 2 of the embodiments that are given below), in which the concentration of the hydroxyl group on the surface of the porous metal oxide semiconductor layer is from 0.01 groups/(nm)2 to 4.0 groups/(nm)2. 20 The invention is also directed to a method for manufacturing a photoelectric conversion device which includes: a first step in which a porous metal oxide semiconductor layer is formed on a surface of a working electrode (for example, the transparent electrode 2 of 25 the embodiments that are given below); a. second step in which the concentration of the hydroxyl group on the surface of the porous metal oxide semiconductor layer is controlled to be from 0.01 groups/(nm)2 to 4.0 groups/(nm)2; and a third step in which the porous metal 30 oxide semiconductor layer is caused to support a dye. 7 EFFECTS OF THE INVENTION According to the invention, there is a working electrode on which a porous metal oxide semiconductor layer is formed to support a dye (for example, the S transparent electrode 2 of the embodiments that are given below) and the concentration of the hydroxyl group on the surface of the porous metal oxide semiconductor layer is from 0,01 groups/(nm)2 to 4.0 groups/(nm)2, and thus it is possible to provide a photoelectric conversion device 10 which has higher conversion efficiency than a photoelectric conversion device having the porous metal oxide semiconductor layer that is formed by coating and calcination of a solution containing dispersion of metal oxide semiconductor particles. 15 Further, according to the invention, since there are a first step in which a porous metal oxide semiconductor layer is formed on a surface of a. working electrode, a second step in which the hydroxyl group concentration of the hydroxyl group on the surface of the 20 porous metal oxide semiconductor layer is controlled to be from 0.01 groups/(nm)2 to 4.0 groups/(nm)2, and a third step in which the porous metal oxide semiconductor layer is caused to support a dye, it is possible to provide a method for manufacturing a photoelectric 25 conversion device which has higher conversion efficiency than a method for manufacturing a photoelectric conversion device which has a step of forming the porous metal oxide semiconductor layer by coating and calcination of a solution containing dispersion of metal 30 oxide semiconductor particles. S BRIEF DESCRIPTION OF DRAWINGS Fig. 1 is a diagram for explaining a configuration of a dye sensitization photoelectric conversion device according to an embodiment of the invention. 5 Fig. 2 is a diagram for explaining (A) a process of forming a window electrode (working electrode) and (B) a process of forming a counter electrode according to a method for manufacturing the dye sensitization photoelectric conversion device as described above. 10 Fig. 3 is a diagram for explaining the relation between concentrations of a. hydroxyl group and adsorbed water and the photoelectric conversion efficiency in a titanium dioxide layer which is used for a dye sensitization photoelectric solar cell of the examples of 15 the invention. Fig. 4 is a diagram for explaining (A) the relation between the concentrations of the hydroxyl group and the photoelectric conversion efficiency, and (B) the relation between the concentration of adsorbed water and the 20 photoelectric conversion efficiency in the titanium dioxide layer as described above. Fig. 5 is a diagram for explaining the relation between the concentrations of the hydroxyl group and adsorbed water and the photoelectric conversion 25 efficiency in the titanium dioxide layer as described above. Fig. 6 is a diagram for explaining the relation between the concentration of the hydroxyl group and the concentration of adsorbed water in the titanium dioxide 30 layer as described above. Fig. 7 is a diagram for explaining (A) the relation 9 among an RF output, the photoelectric conversion efficiency, the concentration of the hydroxyl group, and the concentration of adsorbed water and (B) the relation among the RF output, the concentration of the hydroxyl 5 group, and the concentration of adsorbed water according to plasma treatment of the titanium dioxide layer as described above. Fig. 8 is a diagram for explaining (A) adsorption of the hydroxyl group on a surface of the titanium 10 dioxide layer as described above, and (B) adsorption of the hydroxyl group and water molecules on the surface of the titanium dioxide layer as described above. Fig. 9 is a diagram for explaining an example of the thermal desorption spectrum as described above. 15 MODE FOR CARRYING OUT THE INVENTION The photoelectric conversion device of the invention preferably has a configuration that the concentration of the hydroxyl group is from 0.01 20 groups/(nm)2 to 3.0 groups/(nm)2. According to such a configuration, a photoelectric conversion device having the photoelectric conversion efficiency of 30 or more can be provided. It is more preferable to have a configuration that 25 the concentration of the hydroxyl group is from 0.02 groups/(nm)2 to 2.0 groups/(nm)2. According to such a configuration, a photoelectric conversion device having the photoelectric conversion efficiency of 5°s or more can be provided. 30 It is still more preferable to have a configuration that the concentration of the hydroxyl group is from 0.05 groups/(nm)2 to 0.9 groups/(nm)2. According to such a configuration, a photoelectric conversion device having the photoelectric conversion efficiency of 7% or more can be provided. 5 Further, it is preferable to have a configuration that the concentration of the adsorbed water on the surface of the porous metal oxide semiconductor layer is from 0.03 pieces/(nm)2 to 4.0 pieces/(nm)2. According to such a configuration, it is possible to provide a 10 photoelectric conversion device which has higher conversion efficiency than a photoelectric conversion device having the porous metal. oxide semiconductor layer that is formed by coating and calcination of a solution containing dispersion of metal oxide semiconductor 15 particles. It is more preferable to have a configuration that the concentration of the adsorbed water is from 0.03 pieces/(nm)2 to 3,5 pieces/(nm)2. According to such a configuration, a photoelectric conversion device having 20 the photoelectric conversion efficiency of 3% or more can be provided. It is still more preferable to have a configuration that the concentration of the adsorbed water is from 0.07 pieces/(nm)2 to 2.5 pieces/(nm)2.. According to such a 25 configuration, a photoelectric conversion. device having the photoelectric conversion efficiency of 5% or more can be provided. It is even still more preferable to have a configuration that the concentration of the adsorbed 30 water is from 0.2 pieces/(nm)2 to 2.0 pieces/(nm)2. According to such a configuration, a photoelectric conversion device having the photoelectric conversion efficiency of 70 or more can be provided. As for the method for manufacturing a photoelectric conversion device of the invention, it is preferable to 5 have configuration that the concentration of the hydroxyl group is controlled to be from 0.01 groups/(nm)2 to 3.0 groups/(nm)2. According to such a configuration, a method for manufacturing a photoelectric conversion device having the photoelectric conversion efficiency of 10 3% or more can be provided. It is more preferable to have a configuration that the concentration of the hydroxyl group is controlled to be from 0.02 groups/(nrn)2 to 2.0 groups/(nm)2. According to such a configuration, a method for manufacturing a 15 photoelectric conversion device having the photoelectric conversion efficiency of 5% or more can be provided. It is still more preferable to have a configuration that the concentration of the hydroxyl group is controlled to be from 0.05 groups/(nm)2 to 0.9 20 groups/(nm)2. According to such a configuration, a method for manufacturing a photoelectric conversion device having the photoelectric conversion efficiency of 7% or more can be provided. Further, for the second step described above, it is 25 preferable to have a configuration that the concentration of the adsorbed water on the surface of the porous metal oxide semiconductor layer is controlled to be from 0.05 pieces/(nm)2 to 4,0 pieces/(nm)2. According to such a configuration, it is possible to provide a method for 30 manufacturing a photoelectric conversion device which has higher conversion efficiency than a. photoelectric 12 conversion device having the porous metal oxide semiconductor layer that is formed by coating and calcination of a solution containing dispersion of metal oxide semiconductor particles. 5 It is more preferable to have a configuration that the concentration of the adsorbed water is controlled to be from 0.03 pieces/(nm)2 to 3.5 pieces/(nm)2. According to such a configuration, a method for manufacturing a photoelectric conversion device having the photoelectric 10 conversion efficiency of 3% or more can be provided. It is still more preferable to have a configuration that the concentration of the adsorbed water is controlled to be from 0.07 pieces/(nm)2 to 2.5 pieces/(nm)2. According to such a configuration, a 15 method for manufacturing a photoelectric conversion device having the photoelectric conversion efficiency of 5% or more can be provided. It is even still more preferable to have a configuration that the concentration of the adsorbed 20 water is controlled to be from 0.2 pieces/(nm)2 to 2.0 pieces/(nm)2. According to such a configuration, a method for manufacturing a photoelectric conversion device having the photoelectric conversion efficiency of 7% or more can be provided. 25 Regarding the second step described. above, it is also preferable to have a configuration that the concentration of the hydroxyl. group is controlled by performing at least one of a plasma treatment, a UV irradiation treatment, and a heat treatment of the 30 surface of the porous metal oxide semiconductor layer. According to such a configuration, it is possible to provide a method for manufacturing a. photoelectric conversion device which has higher conversion efficiency than a photoelectric conversion device having the porous metal oxide semiconductor layer that is formed by coating 5 and calcination of a solution containing dispersion of metal oxide semiconductor particles. Further, it is preferable to have a configuration that the plasma treatment is carried out under oxidizing atmosphere. According to such a configuration, it is 10 possible to provide a method for manufacturing a photoelectric conversion device which has higher conversion efficiency than a photoelectric conversion device having the porous metal oxide semiconductor layer that is formed by coating and calcination of a solution 15 containing dispersion of metal oxide semiconductor particles. Further, it is preferable to have a constitution that the plasma treatment is carried out by using any one of parallel plate plasma, barrel plasma, microwave plasma, 20 ECR plasma, helicon wave plasma, hollow cathode discharge plasma, surface wave plasma, and arc jet plasma. According to such constitution, it is possible to provide a method for manufacturing a photoelectric conversion device which has higher conversion efficiency than a 25 photoelectric conversion device having a porous metal oxide semiconductor layer that is formed by coating and calcination of a solution containing dispersion of metal oxide semiconductor particles. Further, for the photoelectric conversion device 30 and the method for manufacturing the same according to the invention, it is preferable to have a constitution 14 that the ratio a, which is defined with the concentration of hydroxyl group and the concentration of adsorbed water, i.e., concentration of hydroxyl group (groups/(nm)2)/{ concentration of hydroxyl group 5 (groups/(nm)2) ± concentration of adsorbed water (pieces/(nm)2)}, is 0.11 or more and 0.45 or less. According to such constitution, it is possible to provide a photoelectric conversion device which has the photoelectric conversion efficiency of 3% or more and a 10 method for manufacturing the same. Further, it is preferable to have a constitution that the ratio a is 0.11 or more and 0,40 or less. According to such constitution, it is possible to provide a photoelectric conversion device which has the 15 photoelectric conversion efficiency of 5% or more and a method for manufacturing the same. Further, it is preferable to have a constitution that the ratio a is 0.11 or more and 0.35 or less. According to such constitution, it is possible to provide 20 a photoelectric conversion device which has the photoelectric conversion efficiency of 7% or more and a method for manufacturing the same. Further, regarding the second step described above, it is preferable to have a constitution that, by 25 controlling the concentration of hydroxyl group by performing a plasma treatment of the surface of the porous metal oxide semiconductor layer, the plasma power (RF output) for the plasma treatment is 1.00 W or more and 700 W or less. According to such constitution, it is 30 possible to provide a photoelectric conversion device which has the photoelectric conversion efficiency of 3% 15 or more and a, method for manufacturing the same. Further, regarding the second step described above, it is preferable to have a constitution that, by controlling the concentration of hydroxyl group by 5 performing a plasma treatment of the surface of the porous metal oxide semiconductor layer, the plasma power (RF output) for the plasma treatment is 180 W or more and 660 W or less. According to such constitution, it is possible to provide a photoelectric conversion device 10 which has the photoelectric conversion efficiency of 5% or more and a method for manufacturing the same. Further, regarding the second step described above, it is preferable to have a constitution that, by controlling the concentration of hydroxyl group by 15 performing a plasma treatment of the surface of the porous metal oxide semiconductor layer, the plasma power (RF output) for the plasma treatment is 300 W or more and 580 W or less. According to such constitution, it is possible to provide a photoelectric conversion device 20 which has the photoelectric conversion efficiency of 7% or more and a method for manufacturing the same. Further, regarding the photoelectric conversion device and method for manufacturing the same according to the invention, it is preferable to have a constitution 25 that the metal oxide semiconductor particles consist of at least one particle of titanium, zinc, tin, and niobium oxide. According to such constitution, it is possible to provide a photoelectric conversion device which has a high photoelectric conversion efficiency and a method for 30 manufacturing the same. Further, the metal oxide semiconductor particles 16 are titanium dioxide particles of brookite type or anatase type. According to such constitution, it is possible to provide a photoelectric conversion device which has a high photoelectric conversion efficiency and 5 a method for manufacturing the same. Further, it is preferable to have a constitution that average primary particle diameter of the metal oxide semiconductor particles is 5 nm or more and 500 nm or less. According to such constitution, it is possible to 10 provide a photoelectric conversion device which has a high photoelectric conversion efficiency and a method for manufacturing the same. Regarding the power generation characteristics of a dye sensitization solar cell, it is very important to 15 control the amount of photosensitizing dye supported on a porous metal oxide semiconductor layer for maximum use of energy caused by light illumination. The most important factor affecting the adsorption amount of a photosensitizing dye is an amount of hydroxyl group or an 20 amount of adsorbed water on a surface of the porous metal oxide semiconductor layer. Kinetic energy of a gas molecule is in much lower state than that of an electron. As such, by forming low temperature plasma having a thermally non-equilibrium 25 state in which the electron temperature is much higher than the ga.s temperature so that temperature of overall system is relatively low, oxygen atom is efficiently dissociated into an elemental nucleus (i.e., ion or neutral radical) and electrons under oxidizing gas 30 atmosphere at low pressure, and it can stably form oxidizing species in a low temperature region. 17 Under oxidizing gas atmosphere at reduced pressure, according to a treatment including generating low temperature plasma and exposing a porous metal oxide semiconductor layer to the low temperature plasma (i.e., 5 low temperature plasma treatment), it is possible to have evaporation or dehydration condensation of adsorbed water on a surface of the porous metal oxide semiconductor layer and to control the concentrations of moisture and hydroxyl group on a surface within a short time by using 10 a simple method. On the other hand, when the porous metal oxide semiconductor layer is heated under normal. atmosphere, from the viewpoint that the latent heat of water is high and energy for dehydration condensation between hydroxyl 15 group is very high, it is very difficult to control the concentrations of moisture and hydroxyl group on a surface of the porous metal oxide semiconductor layer. In this regard, according to the invention, the porous metal oxide semiconductor layer is subjected to 20 low temperature plasma treatment, and therefore evaporation or dehydration condensation of adsorbed water on a surface of the porous metal oxide semiconductor layer can be conveniently achieved at low temperature like temperature below heat resistant temperature of a 25 substrate such as a polymer resin without increasing the temperature of a substrate. As such, it can be easily applied for a dye sensitization solar cell in which a polymer resin substrate is used as a base. Since the dye sensitization solar cell of the 30 invention has a working electrode which consists of a porous metal oxide semiconductor layer supported with a dye, in which the hydroxyl group concentration on the surface is controlled to 0.01 groups/(nm)2 to 4.0 groups/(nm)2 and the adsorbed water concentration on the surface is controlled to 0.03 pieces/(nm)2 to 3.5 5 pieces/(nm)2 by a plasma treatment, a heat treatment, or a UV treatment under oxidizing gas atmosphere, it has high conversion efficiency and can be manufactured by a low temperature process based on simple methods. Herein below, with reference to the drawings, 10 embodiments of the invention are described in greater detail by having a dye sensitization solar cell as an example of a photoelectric conversion device which is constructed to absorb light by photosensitizing dye supported on a porous metal oxide semiconductor layer and 15 to extract the electrons of a photosensitizing dye, which are excited by the light absorption, to outside through the porous metal oxide semiconductor layer. However, the invention can have any constitution which satisfies the activity and effect described above, and it is not 20 limited to the embodiments. Further, the drawings given below are drawn to help clear understanding of the constitution of the invention, and the scale is not exactly accurate. [Embodiments] 25 Fig. 1 is a diagram for describing a configuration of a dye sensitization photoelectric conversion device according to an embodiment of the invention. As illustrated in Fig. 1, the dye sensitization 30 photoelectric conversion device (dye sensitization solar cell) 10 consists of a transparent substrate 1 such as 19 glass, the transparent electrode (negative electrode) 2 consisting of FTO (fluorine-doped tin oxide (IV) Sn02) or the like, the porous metal oxide semiconductor layer 3 supported with a photosensitizing dye, the electrolyte 5 layer 4, the counter electrode (positive electrode) 5, the counter substrate 6, and a. sealing agent (not illustrated). As for the porous metal oxide semiconductor layer 3, a porous layer obtained by calcining microparticles of 10 titanium oxide Ti02 is generally used. On surface of the microparticles which constitute the porous metal oxide semiconductor layer 3, a photosensitizing dye is supported.. The electrolyte layer, 4 is filled in a gap between 15 the porous metal oxide semiconductor layer 3 and the counter electrode 5, and an organic electrolyte liquid containing redox couple species such as I-/13- is used. The counter electrode S consists of the platinum layer 5a and is formed on top of the counter substrate 6. 20 When light enters the dye sensitization photoelectric conversion device 10, the device 10 functions as a cell which has the counter electrode 5 as a positive electrode and the transparent electrode 2 as a negative electrode. Assuming that FTO is used as a 25 material of the transparent electrode 2, N719 is used as a photosensitizing dye (not illustrated), titanium oxide Ti02 is used as a material for the porous metal oxide semiconductor layer 3, and redox species of I-/I3- are used as a redox couple, and the principle of the dye 30 sensitization photoelectric conversion device 10 is described as follows. 20 When photons transmitted the transparent substrate 1 and the transparent electrode 2 are absorbed by a photosensitizing dye, the electrons contained in the photosensitizing dye are excited from a ground state 5 (HOMO) to an excited state (LUMO). The electrons in an excited state are extracted to a conduction band of the porous metal oxide semiconductor layer 3 via an electric bond between the photosensitizing dye and the porous metal oxide semiconductor layer 3, and reach the 10 transparent electrode 2 through the porous metal oxide semiconductor layer 3. Meanwhile, the photosensitizing dye after losing the electrons receives electrons from a reducing agent in the electrolyte layer 4, for example, from I-! based on 15 the reactions 21- > I2 + 2e- and 12 + I > 13, and produces an oxidizing agent, e.g, I3_ (binding product of 12 and I-), in the electrolyte layer 4. Thus, the produced oxidizing agent reaches the counter electrode 5 prepared by diffusion and, according to the reverse 20 reaction of the a.bove-described reaction, i.e., 11 - -> 12 + I- and 12 + 2e. > 21-, it receives the electrons from the counter electrode 5 and is reduced to become the original reducing agent. The electrons transferred from the transparent 25 electrode 2 to an external circuit complete an electric work in the external circuit and are brought back to the counter electrode S. As a result, the photon energy is converted into the electric energy without leaving any change in the photosensitizing dye or in the electrolyte 30 layer 4. As a photosensitizing dye of the dye sensitization 21 photoelectric conversion device 10, a material capable of absorbing light in visible light region, for example, a bipyridine complex, a terpyridine complex, melocyanine dye, porphyrin, and phthalocyanine, are generally used. 5 As a dye which is used singly, cisbis(isothiocyanato)bis(2,2'--bipyridyl-4,4'- dicarboxylic acid) ruthenium (11) 2 tetrabitylammonium complex (common name: N719), which is one kind of a bipyridine complex, is generally used as it has an 10 excellent photosensitizing dye performance. In addition, cisbis(isothiocyanato)bis(2,2'-bipyridyl-4,4'- dicarboxylic acid) ruthenium (II) (common name: N3), which is one kind of a bi.pyridine complex, or tris (isothiocyanato) (2, 2' :6' , 2"-terpyri-dyl-4; 4' , 4"- 15 tricarboxylic acid) ruthenium (11) 3 tetrabitylammonium complex (common name: black dye), which is one kind of a terpyridine complex, is generally used. In particular, when N3 or black dye is used, a coadsorbent is also used frequently. The co-adsorbent is a 20 molecule added for preventing association of dye molecules on the porous metal oxide semiconductor layer 3, and representative examples of the co-adsorbent include kenodeoxycholic acid, taurodeoxy cholate, and 1- decrylphosphonic acid. Those molecules have structural 25 characteristics that a carboxyl group or a phosphono group is contained as a functional group which is easily adsorbed onto titanium oxide of the porous metal oxide semiconductor layer 3 and they are formed with a a bond to prevent an interruption between dye molecules by 30 existing between dye molecules. According to the method for manufacturing the dye 22 sensitization photoelectric conversion device (dye sensitization solar cell) of the invention, a porous metal oxide semiconductor layer is formed, the concentrations of the hydroxyl group and adsorbed water 5 on a surface of the layer are controlled, and a. dye is supported on the porous metal oxide semiconductor layer, and thus it is possible to provide a photoelectric conversion device and a method for manufacturing the same which has higher conversion efficiency than a method for 10 manufacturing a photoelectric conversion device having a porous metal oxide semiconductor layer that is formed by coating and calcination of a solution containing dispersion of metal oxide semiconductor particles. By controlling that, in the porous metal oxide 15 semiconductor layer, the concentration of the hydroxyl group is 0.05 groups/(nm)2 or more and 0.9 groups/(nm)2 or less, the concentration of adsorbed water is 0.2 pieces/(nm)2 to 2.0 pieces/(nm)2, and. ratio a is 0.11 or more and 0.35 or less, a dye sensitization photoelectric 20 conversion device (dye sensitization solar cell) having the photoelectric conversion efficiency of 7% or more can be achieved. As used herein, ratio a represents "concentration of hydroxyl group/(concentration of hydroxyl group + concentration of adsorbed water)." 25 When a resin film is used as a base and the porous metal oxide semiconductor layer is formed on a surface of a transparent electrode formed on the base, the conversion efficiency is preferably improved by heating and calcining the porous metal oxide semiconductor layer 30 within a range in which the base is not deteriorated. The heating within the range in which the base is not 23 deteriorated indicates the temperature of 170°C or lower when PET is used as a base, for example. When the base is PEN, it is 200°C or lower. Heating at the temperature higher than that may cause a problem in production such 5 as distortion of a base. Specific examples of the metal oxide semiconductor particles that are used for forming the porous metal oxide semiconductor layer include titanium oxide, tin oxide, tungsten oxide, zinc oxide, indium oxide, niobium 10 oxide, iron oxide, nickel oxide, cobalt oxide, strontium oxide, tantalum oxide, antimony oxide, lanthanoid oxide, yttrium oxide, and vanadium oxide. If it can form a porous metal oxide semiconductor layer after plasma treatment, has electron conductivity in. a photoexcited 15 state, and can be photoelectrically converted to a visible light and/or near infrared light region by coupling to a. sensitizing dye, it is not limited to those described above. Material of the metal oxide semiconductor particles 20 may be a combination of plural metal oxides. For sensitization of the surface of the porous metal oxide semiconductor layer by a sensitizing dye, the conduction band of the porous metal oxide semiconductor layer is desirably located on a position at which it can easily 25 receive electrons from the photoexcited state of a sensitizing dye. For such reasons, among the metal oxide semiconductor particles, titanium oxide, tin oxide, zinc oxide, and niobium oxide are used in particular. Further, from the viewpoint of cost and environmental hygiene, 30 titanium oxide is used in particular. Preferably, one type of the metal oxide semiconductor particles having 24 average particle diameter of 5 nm to 500 nm or a combination of two or more types of them can be used. As for the transparent conductor layer, it is not particularly limited if it is a conductive material 5 having little light absorption in visible to near infrared region of sunlight. However, metal oxides having good conductivity such as ITO (indium-tin oxide), tin oxide (including those doped with fluorine), and zinc oxide, and carbon are preferable. Under the purpose of 10 promoting binding between the transparent electrode layer and metal oxide particle layer, improving electron transfer, or preventing the reverse electron process, it is possible to have an. additional layer. As for the transparent base, it is not particularly 15 limited if it is a material having little light absorption in visible to near infrared region of sunlight. It is possible to use a glass base such as quartz, a blue plate, BK7, and lead glass and a resin base such as polyethylene terephthalate, polyethylene naphthalate, 20 polyimide, polyester, polyethylene, polycarbonate, polyvinyl butyrate, polypropylene, tet.raacetyl cellulose, syndiotactic polystyrene, polyphenylene sulfide, polyarylate, polysulfone, polyester sulfone, polyether imide, cyclic polyolefi_n, phenoxy bromide, and vinyl 25 chloride. The solvent used for preparing a solution which contains a sensitizing dye used for treatment to support the dye on metal. oxide semiconductor particles needs to be a solvent which can dissolve the sensitizing dye and 30 mediate the dye adsorption onto the metal oxide semiconductor particles. To dissolve the sensitizing dye, 25 it is possible to perform heating, adding a dissolution aid, or filtering insolubles, if required. As a solvent, a mixture of two or more types of the solvent may be used. Examples of the solvent that can be 5 used include alcohol solvents such as ethanol, isopropyl alcohol, and benzyl alcohol, nitrile solvents such as acetonitrile and propionitrile, halogen solvents such as chloroform, dichloromethane, and chlorobenzene, ether solvents such as diethyl ether and tetrahydrofuran, ester 10 solvents such as ethyl acetate and butyl acetate, ketone solvents such as acetone, methyl ethyl ketone, and cyclohexanone, carbonic acid ester solvents such as diethyl carbonate and propylene carbonate, hydrocarbonbased solvents such as hexane, octane, toluene and xylene, 15 dimethyl formamide, dimethyl acetamide, dimethyl sulfoxide, 1,3-dimethyl imidazolinone, N-methyl pyrrolidone, and water, but not limited thereto.. As a solvent, a mixture of two or more types of the solvent may be used. 20 Film thickness of the porous metal oxide semiconductor layer formed on a conductive surface of a transparent base is preferably 0.5 μm or more and 200 μm or less. If the film thickness is less than the range, effective conversion efficiency is not obtained. On the 25 other hand, if the film thickness is thicker than the range, it is difficult to perform the production including that breaking or peeling occurs during film formation and, due to the extended distance between a surface layer of the porous metal oxide semiconductor. 30 layer and the conductive surface, generated charges may not be effectively delivered to the conductive surface, 26 and as a result, favorable conversion efficiency is difficult to obtain. As for the sensitizing dye, a material which can generally absorb light in visible light region, for 5 example, a bipyridine complex, a terpyridine complex, a melocyanine dye, porphyrin, and phthal.ocyanine can be used. As a dye which is used singly, cisbis(isothiocyanato)bis(2,2'-bipyridyl-4,4'- 10 dicarboxylic acid.) ruthenium (II) 2 tetrabitylammonium complex (common name: N719), which is one kind of a bipyridine complex, is generally used as it has an excellent dye performance. Further, examples of the sensitizing dye for 15 photoelectric conversion include azo dyes, quinacridone dyes, diketopyrrolopyrrole dyes, squarilyum dyes, cyanine dyes, mellocyanine dyes, tr_iphenylmethane dyes, xanthene dyes, porphyrin dyes, chlorophyll dyes, ruthenium complex dyes, indigo dyes, perylyene dyes, oxazine dyes, 20 anthraquinone dyes, phthalocyanine dyes, naphthal.oc_yanine dyes, and a derivative thereof. However, if it can absorb light and inject excited electrons to conduction band of a porous metal oxide semiconductor layer (electrode), it is not limited to them. When one or more 25 linking group is contained in the structure of the sensitizing dye, it can be linked to a surface of the porous metal oxide semiconductor layer so that the excited electrons of photoexcited dye can be quickly delivered to the conduction band of the porous metal 30 oxide semiconductor layer, and therefore desirable. The electrolyte layer preferably consists of an 27 electrolyte, a medium, and additives. Preferred examples of the electrolyte include a mixture of 12 and an iodine compound (e.g., LiI, NaI, k(I, CsI, MgI2, CaI2, CuI, tetraalkyl ammonium iodide, pyridinium iodide, and 5 imidazolium iodide) and a mixture of Br2 and a bromine compound (e.g., LiBr). Of these, an electrolyte in which LiI, pyridinium iodide, or imidazolium iodide is mixed as a combination of 12 and an iodine compound is preferable, but it is not limited to this type of combination. 10 Regarding the preferred electrolyte concentration, 12 is 0.01 M or more and 0.5 M or less and. the mixture of iodine compound is 0.1 M or more and 15 M or less in the medium. The medium used for the electrolyte layer is 15 preferably a compound capable of exhibiting good ion conductivity. Examples of the medium in solution state that can be used include an ether compound such as dioxane and diethyl ether, chain type ethers such as ethylene glycol dialkyl ether, propylene glycol dialkyl 20 ether, polyethylene glycol. dialkyl ether, and polypropylene glycol dialkyl ether, alcohols such as methanol, ethanol, ethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, polyethylene glycol monoalkyl ether, and polypropylene glycol monoalkyl ether, 25 polyhydric alcohols such as ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, and glycerin, a nitrile compound such as acetonitrile, glutaronitrile, methxoyacetonitrile, propionitrile, and benzonitrile, a carbonate compound such as ethylene 30 carbonate and propylene carbonate, a heterocyclic compound such as 3-methyl-2-oxazolidinone, and an aprotic 28 polar substance such as dimethyl sulfoxide and sulfolane. A polymer may be also included under the purpose of using a solid phase medium (including gel phase) . For such case, by adding a polymer such as polyacrylonitrile 5 and polyfluorovinylidene to the solution state medium described above, a polyfunctional monomer having an ethylenically unsaturated group is polymerized in the solution state medium to turn the medium into a solid phase. 10 As an electrolyte, an electrolyte which does not require CuI, CuSCN medium, and a. hole transport material such as 2,2',7,'7'-tetrakis(;N,N-di-pmethoxyph. enylamine)9,9'-spi.robifluorene can be used. The counter electrode 5 functions as a positive 15 electrode of a photoelectric conversion cell. Specifically, as a conductive material used for a counter electrode, a metal (for example, platinum, gold, silver, copper, aluminum, rhodium, indium, and the like), metal oxide (ITO (indium-tin oxide) or tin oxide (including 20 those doped with fluorine), zinc oxide), or carbon or the like can be mentioned. Film thickness of the counter electrode is, although not specifically limited, preferably 5 nm or more and 100 .im or less. By combining a window electrode (working electrode) 25 and the counter electrode 5 mediated by an electrolyte layer, a photoelectric conversion cell is formed. If necessary, to avoid leakage or vaporization of an electrolyte layer, sealing is carried out on the periphery of the photoelectric conversion cell. For 30 sealing, a thermoplastic :resin, a. photocurable resin, glass frit, or the like can be used as a sealing material. 29 If necessary, the photoelectric conversion cell produced by connecting photoelectric conversion cells with small area. By combining photoelectric conversion cells in series, the electromotive force can be increased, By increasing the temperature of the porous metal 20 oxide semiconductor layer 3, molecular species can be desorbed from a surface of the porous metal oxide semiconductor layer 3 in an order of from molecular species in weak binding state to molecular species in strong binding state. The molecular species (fragments) 25 can be analyzed by mass spectrometer (MS), and a spectrum in which the intensity of ions of the desired desorbed molecular species is detected as a change in temperature increase can be obtained (herein below, referred to as "thermal desorption spectrum"). The analysis method is 30 also referred. to as temperature programmed desorption (TPD) or thermal desorption gas spectroscopy (TDS). 37 An apparatus for measuring thermal desorption to measure thermal desorption spectrum includes a heating device for heating the porous metal oxide semiconductor layer 3, which is placed in a vacuum chamber, and a mass 5 analyzer connected to the vacuum chamber for detecting the molecular species that are desorbed according to temperature increase. When the discharge rate for discharging the vacuum chamber is sufficiently higher than the pressure change caused by desorbed gas generated 10 from the porous metal oxide semiconductor layer 3, the desorbed gas will never stay in the vacuum chamber, and therefore the amount of desorbed gas at certain time point is proportional to partial pressure of the desorbed gas in the vacuum chamber. 15 The intensity of ions measured by mass spectrometer is proportional to partial pressure, that is, the intensity of ions measured is proportional to the amount of desorbed gas. Thus, by using the area intensity obtained by integration of intensity of ions of the 20 desired desorbed molecular species against the temperature range from the start to the end of desorption, the desired desorbed molecular species that are generated from the porous metal oxide semiconductor layer 3 can be quantitatively obtained according to the quantification 25 method to be described below (see, Non-Patent Document 3). For example, by using a plurality of Si samples injected with a known but different amount of it, proportional coefficient between the hydrogen desorption amount caused by thermal desorption and ion amount for 30 m/z = 2 (area intensity) can be experimentally obtained in advance as an apparatus constant. For the molecular 38 species M that is generated by thermal desorption from the porous metal oxide semiconductor layer 3, by using the ionization difficulty, fragmentation factor, and transmittance for the hydrogen and the molecular species 5 M, the amount of the molecular species M generated by thermal desorption can be quantitatively obtained. When the molecular species M is water to have m/z = 18, the water generated by thermal desorption from the porous metal oxide semiconductor layer 3 can be 10 quantitatively detected as described above. Next, examples relating to the dye sensitization photoelectric conversion device are described. In the Examples and the Comparative Examples, P25 (trade name, manufactured by Nippon AEROSIL, specific surface area of 15 48 m2/g according to BET method, containing titanium oxide of anatase type as a main component) was used as titanium oxide (the surface area according to the BET method was measured by using Belsorp device manufactured by Bel Japan, Inc.). Further, the surface area of the 20 porous metal oxide semiconductor layer was the specific surface area obtained according to the BET method and it was measured by using Belsorp device manufactured by Bel Japan, Inc. Further, the concentrations of the adsorbed water 25 and hydroxyl group on a surface of the porous metal oxide semiconductor layer were measured by analyzing the thermal desorption spectrum measured under the temperature increase rate of 30°C/min by using a thermal desorption analyzer (trade name: WA1000S/W, manufactured 30 by ESCO Co., Ltd.). The lower detection limit for the concentrations of the absorbed water and hydroxyl group 39 is 0.005 pieces/(nm)2. [EXAMPLES] First, in Example 1 to Example 6, the relation 5 between the concentrations of the adsorbed water and hydroxyl group on a surface of the porous metal oxide semiconductor layer and plasma power (that is, RF output) according to plasma treatment is described. [Example 1] 10 A soda lime glass substrate having no absorption in visible light range is used as the transparent substrate 1 and the transparent electrode (transparent electrode layer) 2 having no absorption in visible light range is formed thereon to have thickness of 100 nm according to a 15 standard sputtering method. A dispersion of titanium dioxide was prepared, coated on a surface of the transparent electrode 2, and subjected to a calcination treatment to form a porous metal oxide semiconductor layer. 20 By using titanium dioxide (anatase type) as metal oxide semiconductor particles, the porous metal oxide semiconductor layer (titanium dioxide layer) 3 was formed on a surface of the transparent electrode 2 as follows. By using a bead disperser, 5 g of titanium oxide 25 (Trade name: P25, manufactured by Nippon AEROSIL) was dispersed in a solvent (45 g of ethanol) to prepare a dispersion solution, which was then coated on a surface of the transparent electrode 2 by coating method. Then, it was calcined in an oven at 150°C for 1 hour to form a 30 porous metal oxide semiconductor layer. The resulting porous metal oxide semiconductor 40 layer was subjected to an oxidation treatment under oxygen atmosphere with reduced pressure by using a barrel type apparatus for plasma treatment to control the concentrations of the adsorbed water and hydroxyl group 5 on the surface of the porous metal oxide semiconductor layer to a desired level. Further, the plasma treatment was performed under the plasma treatment condition including gas atmosphere of oxygen (100 6), gas flow amount of 100 sccm, pressure 10 of 100 Pa, RF output of 300 W, and treatment time of 5 min. The resulting porous metal oxide semiconductor layer which has been prepared to have controlled concentrations of the adsorbed water and hydroxyl group 15 as described above has the thickness of 10 μm and the specific surface area of the porous metal. oxide semiconductor layer was 42 m2/g. The concentrations of the adsorbed water and hydroxyl group on a surface of the porous metal oxide 20 semiconductor layer were measured by using a thermal desorption analyzer. As a result, it was found out that the hydroxyl group concentration is 1.0 groups/(nm)2 and the adsorbed water concentration is 2.0 pieces/(nm)2, and the concentrations of the adsorbed water and hydroxyl 25 group are controlled well on a surface of the porous metal oxide semiconductor layer. Meanwhile, the measurement of the concentrations of the adsorbed water and hydroxyl group on a surface of the porous metal oxide semiconductor layer will be described below. 30 Onto the porous metal oxide semiconductor layer obtained after the plasma treatment, a dye was supported 41 as follows. A dye solution in which 25 mg of a dye (cisbis(isothiocyanato)bis(2,2'-bipyridyl-4,4'- dicarboxylic acid) ruthenium (TI) 2 tetrabitylammonium 5 complex (common name: N719)) is contained in 50 mL of ethanol was prepared. The transparent substrate 1 on which the porous metal oxide semiconductor layer is formed was impregnated in the dye solution for dye adsorption, and by washing the transparent substrate 1 on. 10 which the porous metal oxide semiconductor layer is formed with ethanol, excess dyes were removed followed by drying. Next, a spacer made of a resin film (trade name: "HIMILAN" film, manufactured by DUPONT-MITSUI 15 POLYCHEMICALS CO., LTD., those with. thickness of 25 μm were used) was inserted to a peripheral region, and while maintaining a gap, the counter substrate 6 on which the counter electrode 5 is formed and the transparent substrate 1 on which the porous metal oxide semiconductor 20 layer is formed are arranged to face each other. After injecting an electrolyte liquid to the gap, the gap was sealed by using an acrylic UV curable resin. Meanwhile, the electrolyte liquid contains methoxypropionitrile (1.5 g), sodium iodide (0.02 g), 1- 25 propyl-2,3-iododimethyl imidazolium (0.8 g), iodine (0.1 g), and 4-tert-butylpyridine (TBP) (0.05 g). By using the porous metal oxide semiconductor layer as prepared from the above, a dye sensitization solar cell was then manufactured, The dye sensitization solar 30 cell was illuminated with pseudo-sunlight (AN( 1.5, 100 mw/cm2) and short circuit current, open circuit voltage, 42 fill factor (shape factor), and photoelectric conversion efficiency were measured. The dye sensitization solar cell was shown to have the photoelectric conversion efficiency of 7.00. Thus, it was found. out that, by 5 using a porous metal oxide semiconductor layer in which the concentrations of adsorbed water and hydroxyl group are controlled by plasma treatment of a surface, the photoelectric conversion efficiency of a dye sensitization solar cell can be improved. 10 [Example 2] The porous metal oxide semiconductor layer (titanium dioxide layer) 3 that is formed on a surface of the transparent electrode 2 in a similar manner to Example 1 was subjected to an oxidation treatment in a 15 similar manner to Example 1 to control the concentrations of the adsorbed water and hydroxyl group on a surface of the porous metal oxide semiconductor layer to a desired concentration, with the proviso that the plasma treatment was performed under the plasma treatment condition 20 including gas atmosphere of oxygen (1000), gas flow amount of 100 sccm, pressure of 100 Pa, RF output of 200 W, and treatment time of 5 min. The resulting porous metal oxide semiconductor layer which has been prepared to have controlled 25 concentrations of the adsorbed water and hydroxyl group has the thickness of 10 μm and the specific surface area of the porous metal oxide semiconductor layer was 45 m2/g. The concentrations of the adsorbed water and hydroxyl group on a surface of the porous metal oxide 30 semiconductor layer were measured in a similar manner to Example 1 by using a thermal desorption analyzer. As a 4 3 result, it was found out that the hydroxyl group concentration is 1.8 groups/(nm)2 and the adsorbed water concentration is 2.6 pieces/(nm)2, and the concentrations of the adsorbed water and hydroxyl group are controlled 5 well on a surface of the porous metal oxide semiconductor layer. Further, the dye sensitization solar cell was manufactured in a similar manner to Example "1 by using the porous metal oxide semiconductor layer which has 10 controlled. concentrations of the adsorbed water and hydroxyl group according to UV irradiation treatment, and the photoelectric conversion efficiency of the dye sensitization solar cell was found to be 5.5%, which is a favorable value. 15 [Example 3] The porous metal oxide semiconductor layer (titanium dioxide layer) 3 that is formed on a surface of the transparent electrode 2 in a similar manner to Example 1 was subjected to an oxidation treatment in a 20 similar manner to Example 1 to control the concentrations of the adsorbed water and hydroxyl group on a surface of the porous metal oxide semiconductor layer to a desired concentration, with the proviso that the plasma treatment was performed under the plasma treatment condition 25 including gas atmosphere of oxygen (1006), gas flow amount of 100 seem, pressure of 100 Pa, RF output of 100 W, and treatment time of 5 min. The resulting porous metal oxide semiconductor layer which has been prepared to have controlled. 30 concentrations of the adsorbed water and hydroxyl group has the thickness of 10 μm and the specific surface area 44 of the porous metal oxide semiconductor layer was 48 m2/g. The concentrations of the adsorbed water and hydroxyl group on a surface of the porous metal oxide semiconductor layer were measured in a similar manner to 5 Example 1 by using a thermal desorption analyzer. As a result, it was found out that the hydroxyl group concentration is 2.9 groups/(nm)2 and the adsorbed water concentration is 3.5 pieces/(nm)2, and the concentrations of the adsorbed water and hydroxyl group are controlled 10 well on a surface of the porous metal oxide semiconductor layer. Further, the dye sensitization solar cell was manufactured in a similar manner to Example 1 by using the porous metal oxide semiconductor layer which has 15 controlled concentrations of the adsorbed water and hydroxyl group according to UV irradiation treatment, and the photoelectric conversion efficiency of the dye sensitization solar cell was found to be 3.0%, which is a favorable value. 20 [Example 41 The porous metal oxide semiconductor layer (titanium dioxide layer) 3 that is formed on a surface of the transparent electrode 2 in a similar manner to Example 1 was subjected to an oxidation treatment in. a 25 similar manner to Example 1 to control the concentrations of the adsorbed water and hydroxyl group on a surface of the porous metal oxide semiconductor layer to a desired concentration, with the proviso that the plasma treatment was performed under the plasma treatment condition 30 including gas atmosphere of oxygen (1004), gas flow amount of 100 sccm, pressure of 100 Pa, RF output of 400 45 W, and treatment time of 5 min. The resulting porous metal oxide semiconductor layer which has been prepared to have controlled concentrations of the adsorbed water and hydroxyl group S has the thickness of 10 μm and the specific surface area of the porous metal oxide semiconductor layer was 40 m2/g. The concentrations of the adsorbed water and hydroxyl group on a surface of the porous metal oxide semiconductor layer were measured in a similar manner to 10 Example J. by using a thermal desorption analyzer. As a, result, it was found out that the hydroxyl group concentration is 0.5 groups/(nm)Z and the adsorbed water concentration is 1.0 pieces/(nm)2, and the concentrations of the adsorbed water and hydroxyl group are controlled 15 well on a surface of the porous metal oxide semiconductor layer. Further, the dye sensitization solar cell was manufactured in a similar manner to Example 1 by using the porous metal oxide semiconductor layer which has 20 controlled concentrations of the adsorbed. water and hydroxyl group according to UV irradiation treatment, and the photoelectric conversion efficiency of the dye sensitization solar cell was found to be 8.04, which is a favorable value. 25 [Example 5] The porous metal oxide semiconductor layer (titanium dioxide layer) 3 that is formed on a surface of the transparent electrode 2 in a similar manner to Example 1 was subjected to an oxidation treatment in a 30 similar manner to Example 1 to control the concentrations of the adsorbed water and hydroxyl group on a surface of 46 the porous metal oxide semiconductor layer to a desired concentration, with the proviso that the plasma treatment was performed under the plasma treatment condition including gas atmosphere of oxygen (1000), gas flow 5 amount of 100 stem, pressure of 100 Pa, RF output of 500 W, and treatment time of S min. The resulting porous metal oxide semiconductor layer which has been prepared tohave controlled concentrations of the adsorbed water and hydroxyl group 10 has the thickness of 10 pm and the specific surface area of the porous metal oxide semiconductor layer was 37 m2/g. The concentrations of the adsorbed water and hydroxyl group on a surface of the porous metal oxide semiconductor layer were measured in a similar manner to 15 Example 1 by using a thermal desorption analyzer. As a result, it was found out that the hydroxyl group concentration is 0.1 rgoup.5 /(nm) Z and the adsorbed water concentration is 0.5 pieces/(nm)2, and the concentrations of the adsorbed water and hydroxyl group are controlled 20 well on a surface of the porous metal oxide semiconductor layer. Further, the dye sensitization solar cell was manufactured in a similar manner to Example 1 by using the porous metal oxide semiconductor layer which has 25 controlled concentrations of the adsorbed water and hydroxyl group according to UV irradiation treatment, and the photoelectric conversion efficiency of the dye sensitization solar cell was found to be 8.0%, which is a favorable value. 30 [Example 6] The porous metal oxide semiconductor layer 47 (titanium dioxide layer) 3 that is formed on a surface o'E the transparent electrode 2 in a similar manner to Example 1 was subjected to an oxidation treatment in a similar manner to Example 1 to control the concentrations 5 of the adsorbed water and hydroxyl group on a surface of the porous metal oxide semiconductor layer to a desired concentration, with the proviso that the plasma treatment was performed under the plasma treatment condition including gas atmosphere of oxygen (100%), gas flow 10 amount of 100 sccm, pressure of 100 Pa, RF output of 700 W, and treatment time of S min. The resulting porous metal oxide semiconductor layer which has been prepared to have controlled concentrations of the adsorbed water and hydroxyl group 15 has the thickness of 10 μm and the specific surface area of the porous metal oxide semiconductor layer was 36 mz/g. The concentrations of the adsorbed water and hydroxyl. group on a surface of the porous metal oxide semiconductor layer were measured in a similar manner to 20 Example 1 by using a thermal desorption analyzer. As a result, it was found out that the hydroxyl group concentration is 0.01 groups/(nm)2 and the adsorbed water concentration is 0.03 pieces/(nm)2, and the concentrations of the adsorbed water and hydroxyl group 25 are controlled well on a surface of the porous metal oxide semiconductor layer. Further, the dye sensitization solar cell was manufactured in a similar manner to Example 1 by using the porous metal oxide semiconductor layer which has 30 controlled concentrations of the adsorbed water and hydroxyl group according to UV irradiation treatment, and 48 the photoelectric conversion efficiency of the dye sensitization solar cell was found to be 3.006, which is a favorable value. In Example 6, the concentrations of the adsorbed S water and hydroxyl group on a surface of the porous metal oxide semiconductor layer are small, and thus the number of dyes adsorbed onto the porous metal oxide semiconductor layer is lowered. As a result, it was found out that total number of electrons that are excited 10 by light illumination is decreased, and thus the photo conversion efficiency is deteriorated. [Example 7] The porous metal oxide semiconductor layer (titanium dioxide layer) 3 that is formed on a. surface of 15 the transparent electrode 2 in a similar manner to Example 1 was subjected to an atmospheric pressure plasma treatment under atmospheric pressure condition to control the concentrations of the adsorbed water and hydroxyl group on a surface of the porous metal oxide 20 semiconductor layer. Specifically, the plasma treatment was performed for the porous metal oxide semiconductor layer. under the plasma treatment condition including the He gas flow amount of 2000 sccm, oxygen gas flow amount of 100 seem, 25 atmospheric pressure, RF output of 300 W, and treatment time of 5 min. The resulting porous metal oxide semiconductor layer which has been prepared to have controlled concentrations of the adsorbed water and hydroxyl group 30 has the thickness of 10 μm and the specific surface area of the porous metal oxide semiconductor layer was 48 m2/g. 49 The concentrations of the adsorbed water and hydroxyl group on a surface of the porous metal oxide semiconductor layer were measured in a similar manner to Example 1 by using a thermal desorption analyzer. As a 5 result, it was found out that the hydroxyl group concentration is 2.8 groups/(nm)Z and the adsorbed water concentration is 3.8 pieces/(nm)2, and the concentrations of the adsorbed water and hydroxyl group are controlled well on a surface of the porous metal oxide semiconductor 10 layer. Further, the dye sensitization solar cell was manufactured in a similar manner to Example ]. by using the porous metal oxide semiconductor layer which has controlled concentrations of the adsorbed water and 15 hydroxyl group according to atmospheric pressure plasma treatment, and the photoelectric conversion efficiency of the dye sensitization solar cell was found to be 3.5%, which is a favorable value. Next, in Example 8 to Example 10 given below, a 20 method for controlling the concentrations of the adsorbed water and hydroxyl group on a surface of the porous metal oxide semiconductor layer that is obtained without having a plasma treatment is explained. [Example 8] 25 By using a bead disperser, 5 g of titanium oxide (Trade name: P25, manufactured by Nippon AEROSIL) and an additive (titanium ethoxide, 0.5 g) were dispersed is a solvent (45 g of ethanol) to prepare a dispersion solution, which was then coated on a surface of the 30 transparent electrode 2 by coating method. Then, it was calcined in an oven at 150°C for 1 hour to form a porous 50 metal oxide semiconductor layer. The resulting porous metal oxide semiconductor layer was subjected to a heat treatment under ultra-high vacuum (3.0 x 10-7 torr) at 150°C for 60 min. to control 5 the concentrations of the adsorbed water and hydroxyl group on a surface of the porous metal oxide semiconductor layer without having a plasma treatment. The resulting porous metal oxide semiconductor layer which has been prepared. to have controlled 10 concentrations of the adsorbed water and hydroxyl cjroup has the thickness of 10 μm and the specific surface area of the porous metal oxide semiconductor layer was 46 M 2 /g. The concentrations of the adsorbed water and hydroxyl group on a surface of the porous metal oxide 15 semiconductor layer were measured in a similar manner to Example 1 by using a thermal desorption analyzer. As a result, it was found out that the hydroxyl group concentration is 2,0 groups/(nm)2 and the adsorbed water concentration is 2.8 pieces/(nm)2, and the concentrations 20 of the adsorbed water and hydroxyl group are controlled well on a surface of the porous metal oxide semiconductor layer. Further, the dye sensitization solar cell was manufactured in a similar manner to Example 1 by using 25 the porous metal oxide semiconductor layer which has controlled concentrations of the adsorbed water and hydroxyl group according to the heat treatment under ultra-high vacuum, and the photoelectric conversion efficiency of the dye sensitization solar cell was found 30 to be 5.0°06, which is a favorable value. [Example 9] 51 By using a bead disperser, 5 g of titanium oxide (Trade name: P25, manufactured by Nippon AEROSIL) was dispersed in a similar manner to Example 1 in a solvent (45 g of ethanol) to prepare a dispersion solution, which 5 was then coated on a surface of the transparent electrode 2 by coating method. Then, it was calcined in an oven at 150°C for 1 hour to form a porous metal oxide semiconductor layer. The resulting porous metal oxide semiconductor 10 layer was subjected to a CST irradiation treatment using an DV illuminator installed in a vacuum apparatus followed by an oxidation treatment to control the concentrations of the adsorbed water and hydroxyl group on a surface of the porous metal oxide semiconductor 15 layer without having a plasma treatment. The UV irradiation treatment was carried out under the condition that the gas atmosphere is oxygen (100%), pressure is 1x10-' torr, and time for treatment is 5 min. The resulting porous metal oxide semiconductor 20 layer which has been prepared to have controlled concentrations of the adsorbed water and hydroxyl group has the thickness of 10 μm and the specific surface area of the porous metal oxide semiconductor layer was 42 m2/g. The concentrations of the adsorbed water and 25 hydroxyl group on a surface of the porous metal oxide semiconductor layer were measured in a similar manner to Example 1 by using a thermal desorption analyzer.. As a result, it was found out that the hydroxyl group concentration is 1.8 groups/(nm)2 and the adsorbed water 30 concentration is 2.6 pieces/(nm)2, and the concentrations of the adsorbed water and hydroxyl. group are controlled 52 well on a surface of the porous metal oxide semiconductor layer. Further, the dye sensitization solar cell was manufactured in a si_mi_lar manner to Example 1 by using 5 the porous metal oxide semiconductor layer which has controlled concentrations of the adsorbed water and hydroxyl group according to the UV irradiation treatment, and the photoelectric conversion efficiency of the dye sensitization solar cell was found to be 5.50, which is a 10 favorable value. [Example 101 By using a bead disperser, 5 g of titanium oxide (Trade name: P25, manufactured by Nippon AEROSIL) was dispersed in a similar manner to Example 1 in a solvent 15 (45 g of ethanol) to prepare a dispersion solution, which was then coated on a surface of the transparent electrode 2 by coating method. Then, it was calcined in an oven. at 150°C for 1 hour to form a porous metal oxide semiconductor layer. 20 The resulting porous metal oxide semiconductor layer was subjected to a UV irradiation treatment using an UV illuminator under atmospheric condition followed by an oxidation treatment to control the concentrations of the adsorbed water and hydroxyl group an a surface of the 25 porous metal oxide semiconductor layer without having a. plasma treatment. The UV irradiation treatment was carried out under the condition that time for UV treatment is 5 min, The resulting porous metal oxide semiconductor 30 layer which has been prepared to have controlled concentrations of the adsorbed water and :hydroxyl. group has the thickness of 10 μm and the specific surface area of the porous metal oxide semiconductor layer was 48 m2/g. The concentrations of the adsorbed water and hydroxyl group on a surface of the porous metal oxide 5 semiconductor layer were measured in a similar manner to Example 1 by using a thermal desorption analyzer. As a result, it was found out that the hydroxyl group concentration is 3.3 groups/(nm)Z and the adsorbed water concentration is 3.7 pieces/(nm)2. Further, the 10 photoelectric conversion efficiency of the dye sensitization solar cell which uses the above porous metal oxide semiconductor layer was found to be 20, which is a favorable value. In Example 12 to Example 16 that are explained 15 below, the concentrations of the adsorbed water and hydroxyl group on a surface of the porous metal oxide semiconductor layer were controlled by performing a plasma treatment under the gas with reduced pressure other than oxygen, in which the porous metal oxide 20 semiconductor layer 3 (titanium dioxide layer) is formed on a surface of the transparent electrode 2 in a similar manner to Example 1. In Example 11 to Example 15 that are explained below, the plasma treatment was carried out for the 25 porous metal oxide semiconductor layer under the plasma treatment condition including gas atmosphere other than oxygen (1000), the gas flow amount of 100 sccm, pressure of 100 Pa, RF output of 300 W, and treatment time of 5 min. The concentrations of the adsorbed water and 30 hydroxyl group on a surface of the porous meta.]. oxide semiconductor layer were measured in a similar manner to 54 Example 1 and the photoelectric conversion efficiency of the dye sensitization solar cell which uses the porous metal oxide semiconductor layer was also measured. [Example 111 5 When the gas atmosphere is carbon monoxide (CO), the porous metal oxide semiconductor layer which has been prepared to have controlled concentrations of the adsorbed water and hydroxyl group by the plasma treatment has the thickness of 10 μm and the specific surface area 10 of the porous metal oxide semiconductor layer was 45 m2/g. The concentrations of the adsorbed water and hydroxyl group on a surface of the porous metal oxide semiconductor layer were measured in a similar manner to Example 1 by using a thermal desorption analyzer. As a 15 result, it was found out that on a surface of the porous metal oxide semiconductor layer the hydroxyl group concentration is 2.0 groups/(nm)2 and the adsorbed water concentration is 2.8 pieces/(nm)2, and the photoelectric conversion efficiency of the dye sensitization solar cell 20 using the porous metal oxide semiconductor layer was found to be 5.0%, which is a favorable value. [Example 12] When the gas atmosphere is carbon dioxide (C02) the porous metal oxide semiconductor layer which has been 25 prepared to have controlled concentrations of the adsorbed water and hydroxyl group by the plasma treatment has the thickness of 10 p.im and the specific surface area of the porous metal oxide semiconductor layer was 45 m2/g. The concentrations of the adsorbed water and 30 hydroxyl group on a surface of the porous metal oxide semiconductor layer were measured in the same manner as 55 Example 1 by using a thermal desorption analyzer. As a result, it was found out that on a surface of the porous metal oxide semiconductor layer, the hydroxyl group concentration is 2.0 groups /( nm)2 and the adsorbed water 5 concentration is 2.8 pieces/(nm)2, and the photoelectric conversion efficiency of the dye sensitization solar cell using the porous metal oxide semiconductor layer was found to be 5.0%, which is a favorable value. [Example 13] 10 When the gas atmosphere is nitric monoxide (NO), the porous metal oxide semiconductor layer which has been prepared to have controlled concentrations of the adsorbed water and hydroxyl group by the plasma treatment has the thickness of 10 μm and the specific surface area 15 of the porous metal oxide semiconductor layer was 45 m2/g. The concentrations of the adsorbed water and hydroxyl group on a surface of the porous metal oxide semiconductor layer were measured in the same manner as Example 1 by using a thermal desorption analyzer. As a 20 result , it was found out that on a surface of the porous metal oxide semiconductor layer, the hydroxyl group concentration i s 2.5 groups/(nm)' and the adsorbed water concentration i s 3.2 pieces /( nm)2, and the photoelectric conversion efficiency of the dye sensitization solar cell 25 using the porous metal oxide semiconductor layer was found to be 4.0%, which is a. favorable value. (Example 14] When the gas atmosphere i s nitric dioxide (NO2), the porous metal oxide semiconductor layer which has been 30 prepared to have controlled concentrations of the adsorbed water and hydroxyl group by the plasma treatment 56 has the thickness of 10 μm and the specific surface area of the porous metal oxide semiconductor layer was 45 m`/g. The concentrations of the adsorbed water and hydroxyl group on a surface of the porous metal oxide 5 semiconductor layer were measured in the same manner as Example 1 by using a thermal desorption analyzer. As a result, it was found out that on a surface of the porous metal oxide semiconductor layer, the hydroxyl group concentration is 2.5 groups/(nm)2 and the adsorbed water 10 concentration is 3.2 pieces /(nm) 2 and the photoelectric conversion efficiency of the dye sensitization solar cell using the porous metal oxide semiconductor layer was found to be 4.0%, which is a favorable value. [Example 15] 15 When the gas atmosphere is nitrogen dioxide (N20), the porous metal. oxide semiconductor layer which has been prepared to have controlled concentrations of the adsorbed water and hydroxyl group by the plasma treatment has the thickness of 10 [.lm and the specific surface area 20 of the porous metal oxide semiconductor layer was 45 m2/g. The concentrations of the adsorbed water and hydroxyl group on a surface of the porous metal oxide semiconductor layer were measured in the same manner as Example 1 by using a thermal desorption analyzer. As a 25 result, it was found out that on a surface of the porous metal oxide semiconductor layer, the hydroxyl group concentration is 2.5 groups/(nm)2 and the adsorbed water concentration is 3,2 pieces/(nm)2, and the photoelectric conversion efficiency of the dye sensitization solar cell 30 using the porous metal oxide semiconductor layer was found to be 4.0°06, which is a favorable value. 57 [Example 16] In Example 1 to Example 15, the oxidation treatment of the porous metal oxide semiconductor layer was performed by using a barrel type plasma treatment 5 apparatus. However, in Example 16, the oxidation treatment of the porous metal oxide semiconductor layer (titanium dioxide layer) 3, which has been formed on a surface of the transparent electrode 2 in the same manner as Example 1, was performed by using a. parallel plate 10 type plasma treatment apparatus under oxygen atmosphere with reduced pressure to control the concentrations of adsorbed water and hydroxyl group on a surface of the porous metal oxide semiconductor layer. Further, with the plasma generated by parallel 15 plate anode couple method. (frequency of 13.56 MHz), the plasma treatment was carried out under the plasma treatment condition including gas atmosphere of oxygen. (100%), the gas flow amount of 100 sccm, pressure of 100 Pa, RF output of 300 W, and treatment time of 5 min. 20 As a result, the porous metal oxide semiconductor layer which has been prepared to have controlled concentrations of the adsorbed water and hydroxyl group has the thickness of 10 μm and the specific surface area of the porous metal oxide semiconductor layer was 43 m2/g. 25 Further, the concentrations of the adsorbed water and hydroxyl group on a surface of the porous metal oxide semiconductor layer were measured in the same manner as Example 1 and the photoelectric conversion efficiency of the dye sensitization solar cell. which uses the porous 30 metal oxide semiconductor layer were also measured. As a result, it was found out that concentrations of the 58 adsorbed water and hydroxyl group on a. surface of the porous metal oxide semiconductor layer were 2.8 pieces/(nm)2 and 2.0 groups/(nm)2, respectively, and the photoelectric conversion efficiency was found to be 5.0%, 5 which is a favorable value, [Comparative Example 1] The porous metal oxide semiconductor layer of Comparative Example 1 is the same as the porous metal oxide semiconductor layer of Example 1 except that it is 10 in a state before performing an oxidation trea.tmen. using a barrel type plasma treatment apparatus. Specifically, by using a bead disperser, 5 g of titanium oxide (Trade name: P25, manufactured by Nippon AEROSIL) was dispersed in the same manner as Example 1 in a solvent (45 g of 15 ethanol) to prepare a dispersion solution, which was then coated on a surface of the transparent electrode 2 by a coating method. Then, it was calcined in an oven at 150°C for 1 hour to form a. porous metal oxide semiconductor layer. 20 The resulting porous metal oxide semiconductor layer has the thickness of 10 lLm and the specific surface area of the porous metal oxide semiconductor layer was 50 m2/g• The concentrations of the adsorbed water and 25 hydroxyl group on a surface of the porous metal oxide semiconductor layer were measured in the same manner as Example 1 by using a thermal desorption analyzer. As a result, it was found out that the concentrations of the hydroxyl group and adsorbed water were 4.5 groups/(nm)2 30 and 4.5 pieces/(nm)2, respectively. Further, the dye sensitization solar cell that is 59 manufactured by using the porous metal oxide semiconductor layer which has been supported with a dye in the same manner as Example 1 was tested for short circuit current, open circuit voltage, fill factor (shape 5 factor), and photoelectric conversion efficiency in the same manner as Example 1. As a. result, the photoelectric conversion efficiency was found to be 1.0%. Results of the Examples that are explained in the 10 above are given below. Fig. 3 is a drawing for explaining the condition for forming the titanium dioxide layer used for the dye sensitization solar cell of the Examples of the invention, and the relation among the hydroxyl group concentration, 20 the adsorbed water concentration, and the photoelectric conversion efficiency in the titanium dioxide layer. The condition for forming the layer only as illustrated in Fig. 3 represents an outline of the method for forming the titanium dioxide electrode layer that is explained in 25 each example described above. Fig. 4 is a drawing for explaining the relation between concentrations of hydroxyl group and adsorbed water on a surface of the titanium dioxide layer of the Examples of the invention and photoelectric conversion 30 efficiency. Fig. 4(A) illustrates a smooth curve obtained from 60 plotting of the relation between the hydroxyl group concentration and photoelectric conversion efficiency that is illustrated in Fig. 3, in which the horizontal axis represents the concentration of hydroxyl group 5 (groups/(nm)2) and the vertical axis represents the photoelectric conversion efficiency (a). Fig. 4(B) illustrates a smooth curve obtained from plotting of the relation between the adsorbed water concentration and the photoelectric conversion efficiency 10 that is illustrated in Fig. 3, in which the horizontal axis represents the concentration of adsorbed water (pieces/(nm)2) and the vertical axis represents the photoelectric conversion efficiency (%). As illustrated in Fig. 3 and Fig, 4, the 15 photoelectric conversion efficiency of the dye sensitization solar cell is higher in every Example compared to Comparative Example 1. As illustrated in Fig. 4(A), the photoelectric conversion efficiency increases to the maximum in 20 accordance with the increase in hydroxyl group concentration an a surface of the titanium dioxide electrode layer (porous metal oxide semiconductor layer), and as the hydroxyl group concentration is further increased, the photoelectric conversion efficiency starts 25 to decrease. The maximum value obtained for the photoelectric conversion efficiency when the hydroxyl group concentration on a surface of the titanium dioxide electrode layer is changed indicates that, as described 30 in Patent Document 1, it is impossible to increase the photoelectric conversion efficiency to its maximum and 61 have it in a desirable state only by increasing the adsorption amount of a dye based on increased hydroxyl group concentration on a surface by plasma treatment of a titanium dioxide layer, and thus to have the 5 photoelectric conversion efficiency equal to or larger than a certain value, there is a desirable hydroxyl group concentration range. As illustrated in Fig. 4(A), when the hydroxyl group concentration on a surface of the titanium dioxide 10 electrode layer (porous metal oxide semiconductor Layer) is controlled to 0.01. groups/(nm)2 to 4.0 groups/(nm)2, a dye sensitization solar cell having higher photoelectric conversion efficiency than Comparative Example 1 can be achieved. 15 Further, when the hydroxyl group concentration on a surface of the titanium dioxide electrode layer (porous metal oxide semiconductor layer) is controlled to 0.01 groups/(nm)2 to 3.0 groups/ (:am) 2 , a dye sensitization solar cell having photoelectric conversion efficiency 20 equal to or higher than 3% can be achieved. Further, when the hydroxyl group concentration on a surface of the titanium dioxide electrode layer (porous metal oxide semiconductor layer) is controlled to 0.02 groups/(nm)2 to 2.0 groups/(nm)2, a dye sensitization 25 solar cell having photoelectric conversion efficiency equal to or higher than 5o can be achieved. Still further, when the hydroxyl group concentration on a surface of the titanium dioxide electrode layer (porous metal oxide semiconductor layer) 30 is controlled to 0.05 groups/(nm)2 to 0.9 groups/(nm)2, a dye sensitization solar cell having photoelectric 62 conversion efficiency equal to or higher than 796 can be achieved. As illustrated in Fig. 4(B), the photoelectric conversion efficiency increases to the maximum in 5 accordance with the increase in adsorbed water concentration on a surface of the titanium dioxide electrode layer (porous metal oxide semiconductor layer), and as the adsorbed water concentration is further increased, the photoelectric conversion efficiency starts 10 to decrease. As illustrated in Fig. 4(B), when the adsorbed water concentration on a surface of the titanium dioxide electrode layer (porous metal oxide semiconductor layer) is controlled to 0.03 pieces/(nm)2 to 4.0 pieces/(nm)2, a 15 dye sensitization solar cell having higher photoelectric conversion efficiency than Comparative Example 1 can be achieved. Further, when the adsorbed water concentration on a surface of the titanium dioxide electrode layer (porous 20 metal oxide semiconductor layer) is controlled to 0.03 pieces/(nm)2 to 3.5 pieces/(nm)2, a dye sensitization solar cell having photoelectric conversion efficiency equal to or higher than 3% can be achieved. Further, when the adsorbed water concentration on a 25 surface of the titanium dioxide electrode layer (porous metal oxide semiconductor layer) is controlled to 0.07 pieces/(nm)2 to 2.5 pieces/(nm)2, a dye sensitization solar cell having photoelectric conversion efficiency equal to or higher than 5% can be achieved. 30 Still further, when the adsorbed water concentration on a surface of the titanium dioxide 63 electrode layer (porous metal oxide semiconductor layer) is controlled to 0.2 pieces/(nm)2 to 2.0 pieces/(nm)2, a dye sensitization solar cell having photoelectric conversion efficiency equal to or higher than 7% can be 5 achieved. Fig. 5 is a drawing for explaining the relation between the concentrations of hydroxyl group and adsorbed water on a surface of the titanium dioxide layer of the Examples of the invention and photoelectric conversion 10 efficiency. In Fig. 5, the horizontal axis represents [concentration of hydroxyl group (groups! (nm) 2)]! [(concentration of hydroxyl group (groups/(nm)2)) + (concentration of adsorbed water 15 (pieces/(nm)2))]} and the vertical axis represents the photoelectric conversion efficiency (%) . In the explanations given below, the ratio defined by {[concentration of hydroxyl group (groups! (nm) 2)] / [(concentration of hydroxyl group 20 (groups/(nm)2)) + (concentration of adsorbed water (pieces/(nm)2))]} is taken as a. Fig. 5 illustrates a smooth curve obtained from result of plotting the photoelectric conversion efficiency against a calculated from the results of Fig, 3. In Fig. 5, the result 25 corresponding to Example 6 is outside the illustrated curve, as it has a small adsorbed water concentration and a large measurement error. As illustrated in Fig. 5, when the concentrations of the hydroxyl group and adsorbed water on a surface of 30 the titanium dioxide electrode layer (porous meta]. oxide semiconductor layer) are controlled such that the ratio a 64 is 0.11 or more and 0.45 or less, a dye sensitization solar cell having photoelectric conversion efficiency equal to or higher than 3% and also a method for manufacturing the dye sensitization solar cell can be 5 provided. Further, when the concentrations of the hydroxyl group and adsorbed water on a surface of the titanium dioxide electrode layer (porous metal oxide semiconductor layer) are controlled such that the ratio a is 0.11 or 10 more and 0.40 or less, a dye sensitization solar cull having photoelectric conversion efficiency equal to or higher than 5% and also a method for manufacturing the dye sensitization solar cell can be provided. Still further, when the concentrations of the 15 hydroxyl group and adsorbed water on a surface of the titanium dioxide electrode layer (porous metal oxide semiconductor layer) are controlled such that the ratio a is 0.11 or more and 0.35 or less, a dye sensitization solar cell having photoelectric conversion efficiency 20 equal to or higher than 76 and also a method for manufacturing the dye sensitization solar cell can be provided. Fig. 6 is a drawing for explaining the relation between the concentration of the hydroxyl group and the 25 concentration of the adsorbed water on a surface of the titanium dioxide layer of the Examples of the invention. In Fig. 6, the horizontal axis represents the concentration of hydroxyl group (groups/ (11M) 2) and the vertical axis represents the concentration of adsorbed 30 water (pieces/(nm)2). As illustrated. in Fig. 6, the hydroxyl group 65 concentration and the adsorbed water concentration on a surface of the titanium dioxide layer have approximately linear relation, indicating that the adsorbed water concentration increases in accordance with an increase in 5 the hydroxyl group concentration on a surface of the titanium dioxide layer. Further, in Fig. 6, the result corresponding to Example 6 is outside the illustrated curve, as it has small concentrations of hydroxyl group and adsorbed water and a large measurement error. 10 Fig. 7 is a drawing in which the results of Fig. 3 are illustrated as a graph, explaining the relation between RF output (plasma power) according to plasma treatment of the titanium dioxide layer and photoelectric conversion efficiency and the relation among.; the RF 15 output and the concentration of hydroxyl group and the concentration of adsorbed water on a surface of the titanium dioxide layer as described in the Examples of the invention. Specifically, Fig. 7(A) is a linear plot for representing the relation among the R.F output, the 20 photoelectric conversion efficiency, the concentration of hydroxyl group, and the concentration of adsorbed water according to the plasma treatment and Fig. 7(B) is a. semi-log plot for representing the relation among the RF output according to the plasma treatment, the 25 concentration of hydroxyl group, and the concentration of adsorbed water. In Fig. 7(A), the horizontal axis represents R)- output according to the plasma treatment, the left vertical axis represents the photoelectric conversion 30 efficiency (o), and the right vertical axis represents the concentrations of hydroxyl. group and adsorbed water 66 (pieces/(nm)2). In Fig. '7(B), the horizontal axis represents theRF output according to the plasma treatment, the left vertical axis represents the concentrations of hydroxyl group and adsorbed water 5 (pieces/ (nut )2). As illustrated in Fig. 7(A) and Fig. 7(B), the concentrations of both the hydroxyl group and adsorbed water on a surface of the titanium dioxide layer decrease in accordance with the increase in RF output, and as the 10 RF output according to the plasma treatment increases, the photoelectric conversion efficiency is increased to the maximum and then starts to decrease. These results suggest that the concentration of hydroxyl group and adsorbed water can be controlled according to the 15 progress of evaporation or dehydration condensation of adsorbed water on a surface of the porous metal oxide semiconductor layer (titanium dioxide layer) by controlling the RF output according to a plasma treatment, and therefore it becomes possible to enhance the 20 photoelectric conversion efficiency of a dye sensitization solar cell. As illustrated in Fig. 7(A), when the plasma power (RF output) for the plasma treatment is controlled to 100 W to 700 W, a photoelectric conversion device having 25 photoelectric conversion efficiency equal to or higher than 3o and also a method for manufacturing the device can be provided. Further, when the plasma power (RF output) according to the plasma treatment is controlled to 180 W 30 to 660 W, a. photoelectric conversion device having photoelectric conversion efficiency equal to or higher 67 than 54 and also a method for manufacturing the device can be provided. Still further, when the plasma power (RF output) according to the plasma treatment is controlled to 300 W 5 to 580 W, a photoelectric conversion. device having photoelectric conversion efficiency equal to or higher than 7% and also a method for manufacturing the device can be provided. As it is evident from the results illustrated in 10 Fig. 3 to Fig. 7, Comparative Example 1 has higher concentrations of hydroxyl group and adsorbed water than any of the Examples, while it has low photoelectric conversion efficiency. Thus, it is clearly shown that, the concentrations of the hydroxyl group and.' adsorbed 15 water on a surface of the porous metal oxide semiconductor layer (titanium dioxide layer) are one of the most important factors for determining the photoelectric conversion efficiency of a photoelectric conversion device (dye sensitization solar cell). 20 In this regard, it is believed that the amount (number of molecules) of the dye which is bonded and supported onto a surface of the porous metal oxide semiconductor layer is greatly affected by the concentrations of the hydroxyl group and adsorbed water 25 on a surface of the porous metal oxide semiconductor layer and the amount (number of molecules) of supported dye and the state of dye supported on the surface have a huge influence on the photoelectric conversion efficiency of a photoelectric conversion device (dye sensitization 30 solar cell). Fig, 8 is a drawing for explaining the adsorption 68 of hydroxyl group and adsorbed water on a surface of the titanium dioxide layer of the Examples of the invention. Specifically, Fig. 8(A) diagrammatically represents adsorption of the hydroxyl group on a surface of the 5 titanium dioxide layer and Fig. 8(B) diagrammatically represents adsorption of the hydroxyl group and adsorbed water on a surface of the titanium dioxide layer. As illustrated in Fig. 8(A), it is believed that the hydroxyl groups (chemically adsorbed water) including 10 terminal hydroxyl group (i.e., hydroxyl. group (-OH) bound to titanium atom) 15 and the bridge hydroxyl group (i.e., hydroxyl group (-OH) bound to adjacent two titanium atoms) 13 are present on a surface of the titanium dioxide layer 11. Further, as illustrated in Fig. 8 (B) , 15 it is believed that water (physically adsorbed water) is adsorbed to the hydroxyl groups via. hydrogen bond. As illustrated. in Fig. 8(B), water molecules bind to the hydroxyl group 13 and 15 on a surface of the titanium dioxide layer 11 via hydrogen bond 17, yielding 20 the water molecule layer (physically adsorbed layer) 19 prepared by physical adsorption. As a type of hydrogen bond, the hydrogen bond between the hydrogen (H) atom in Ti-OH and the oxygen (0) atom in water molecule H2O (that is, first type), and the hydrogen bond between the oxygen 25 (0) atom in Ti-OH and the hydrogen (H) atom in water molecule H2O (that is, second type) can be considered. However, only the first type is illustrated in Fig. 8(B). Generally, in order for the photosensitizing dye used for a dye sensitization solar cell to have an 30 activity of binding and adsorbing of a dye onto a surface of a porous metal oxide semiconductor layer, and to form 69 a bond between porous metal oxide semiconductor layer for promoting electron transfer between the dye excited by light illumination and conduction band of a porous oxide semiconductor layer, it contains an interlock group such 5 as a carboxyl group, an alkoxy group, a hydroxyl group, a hydroxyalkyl group, a sulfon.ic acid group, an ester group, a mercapto group, and a phosphonyl group in. the molecular structure of a dye. In accordance with a binding reaction between a 10 hydroxyl group on a surface of a porous metal oxide semiconductor layer such as a titanium dioxide layer and an interlock group of a dye, stable binding and adsorption onto a surface of the porous meta]. oxide semiconductor layer are achieved. For such reasons, the 15 hydroxyl group concentration on a surface of the porous metal oxide semiconductor layer is an important parameter which determines the adsorption amount of a photosensitizing dye. Since the adsorption amount of a photosensitizing dye increases as the hydroxyl group 20 concentration on a surface of the porous metal oxide semiconductor layer is increased, the number of electrons that are generated as a result of excitation of an adsorbed photosensitizing dye by light (sunlight) illumination increases, and thus photoelectric conversion 25 efficiency of the dye sensitization solar cell is improved. However, when the hydroxyl group concentration on a surface of the porous metal oxide semiconductor layer is excessively high, multi-molecular adsorption of the 30 photosensitizing dye onto a. surface of the porous metal oxide semiconductor layer occurs. Even when only one 70 photosensitizing dye among multi-molecularly adsorbed molecules is excited to generate electrons, they are absorbed by other photosensitizing dye of the multimolecularly adsorbed molecules, and as a result, it 5 cannot reach the photosensitizing dye which is adsorbed on a site at which electrons can efficiently move in the porous metal oxide semiconductor layer. Consequently, it cannot efficiently contribute to generation of electromotive force. 10 Further, when the hydroxyl group concentration on a surface of the porous metal oxide semiconductor layer increases, hydrophilicity is improved, and as a result, water molecules bind to the hydroxyl group via hydrogen bond and, prepared by physical adsorption, physically 15 adsorbed water layer is formed to have increased concentration of adsorbed water which is physically adsorbed as illustrated in Fig. 3(U). Since the photosensitizing dye can bind to adsorbed water of the physically adsorbed layer via hydrogen bond, multi- 20 molecular adsorption of the photosensitizing dye is promoted more as the adsorbed water concentration on the surface increases. Even when the photosensitizing dye which binds to the physically adsorbed water via hydrogen bond is 2S excited by light illumination to generate electrons, they move toward the porous metal oxide semiconductor layer through the physically adsorbed layer, and thus it cannot efficiently contribute to generation of electromotive force. 30 According to the invention, hyd.roxyl group concentration on a surface of the porous metal oxide 71 semiconductor layer to which the photosensitizing dye of a single-molecular layer is supported is controlled to the concentration range in which the electrons excited and generated from the photosensitizing dye by light 5 illumination can move efficiently toward the porous metal oxide semiconductor layer and can efficiently contribute to generation of an electromotive force. As described before, evaporation or dehydration condensation of adsorbed water on a surface of the porous 10 metal oxide semiconductor layer can be promoted by plasma treatment of a surface of the porous metal oxide semiconductor layer, and therefore the hydroxyl group concentration on a surface of the porous metal oxide semiconductor layer can be controlled to a desired range 15 according to plasma condition or the like required for the plasma treatment. In addition, it is desirable to figure out in advance the relations between the hydroxyl group concentration on a surface of the porous metal oxide semiconductor layer and the plasma condition or the 20 like required for the plasma treatment. Next, examples of thermal desorption spectrum will be described. Fig. 9 is a diagram for explaining an example of the thermal desorption spectrum for mass charge ratio m/z 25 = 18 as described in Example 1 of the invention. In Fig. 9, the horizontal axis indicates the temperature (°C) and the vertical axis represents intensity of ions (arbitrary unit) for m/z = 18. According to the example illustrated in Fig. 9, the 30 thermal desorption spectrum exhibits a bimodal curve. After separating the bimodal curve into two curves, that 72 is, curve (a) and curve (b), area strength is obtained for each curve. It is believed that the curve (b) is based on ionization of water, which is desorbed from adsorbed water bonded to a titanium oxide layer based on 5 hydrogen bond 17 as described before in view of Fig. 8, and according to the quantification method described before, the concentration of adsorbed water is quantitatively obtained. It is also believed that the curve (a) is based on ionization of water, which is 10 desorbed from a. titanium oxide layer based on dehydration condensation of (2Ti-OH 3 'Ti-OH + H2O) hydroxyl group (- OH) 13 and 15 which bind to Ti. atom as illustrated in Fig. 8, and water concentration is quantitatively obtained by the quantification method described before and the result 15 is converted into the concentration of hydroxyl group. As described above, according to the invention, the concentration of hydroxyl group and the concentration of adsorbed water on a surface of the porous metal oxide semiconductor layer are controlled to enhance the 20 photoelectric conversion efficiency of a photoelectric conversion device such as a dye sensitization solar cell. Accordingly, the amount of dye which is supported and bind to a surface of the porous metal oxide semiconductor layer can be controlled and the energy generated by light 25 illumination can be utilized to maximum level as an electromotive force. As a result, the porous metal oxide semiconductor layer of the present invention has better characteristics than a porous metal oxide semiconductor layer which is formed by coating and calcination of a 30 solution containing dispersion of metal oxide semiconductor particles. 73 While the aspects of the present invention have been described above, the invention is not limited to them. Instead, it should be understood that various modifications can be made based on the technical idea. of 5 the invention. INDUSTRIAL APPLICABILITY According to the invention, a photoelectric conversion device having high conversion efficiency and a 10 method for manufacturing the same can be provided. REFERENCE SIGNS LIST 1 Transparent substrate 2 Transparent electrode 15 3 Porous metal oxide semiconductor layer supported with photosensitizing dye 4 Electrolyte layer 5 Counter electrode Sa Platinum layer 20 Sb Transparent conductor layer 6 Counter substrate 10 Dye sensitization photoelectric conversion device 11 Titanium dioxide layer 13 Bridge hydroxyl group 25 15 Terminal hydroxyl group 17 Hydrogen bond 19 Layer of water molecules prepared by physical adsorption 74 CLAIMS 1. A photoelectric conversion device comprising: a working electrode on which a porous metal oxide 5 semiconductor layer is formed to support a dye„ wherein a concentration of hydroxyl group on a surface of the porous metal oxide semiconductor layer is 0.01 groups/(nm)2 or more and 4.0 groups/(nm)2 or less. 10 2. The photoelectric conversion device according to claim 1, wherein the concentration of hydroxyl group is 0.01 groups/(nm)2 or more and 3.0 groups/(nm)2 or less. 3. The photoelectric conversion device according to 15 claim 1, wherein the concentration of hydroxyl group is 0.02 groups/(nm)2 or more and 2.0 groups/(nm)2 or less. 4. The photoelectric conversion device according to claim 1, wherein the concentration of hydroxyl group is 20 0.05 groups/(nm)2 or more and 0.9 groups/ (nm)2 or less. 5. The photoelectric conversion device according to claim 1, wherein the concentration of adsorbed water on the surface of the porous metal oxide semiconductor layer 25 is 0.03 pieces/(nm)2 or more and 4.0 pieces/(nm)2 or less. 6. The photoelectric conversion device according to claim 1, wherein the concentration of adsorbed water is 0.03 pieces/(nm)2 or more and 3.5 pieces/(nm)2 or less. 30 7. The photoelectric conversion device according to 75 claim 1, wherein the concentration of adsorbed water is 0.07 pieces/(nm)2 or more and 2.5 pieces/(nm)2 or less. 8. The photoelectric conversion device according to 5 claim 1, wherein the concentration of adsorbed water is 0,2 pieces/(nm)2 or more and 2.0 pieces/(nm)2 or less. 9. A method for manufacturing a photoelectric conversion device, the method comprising: 10 a first step of forming a porous metal oxide semiconductor layer on a surface of a working electrode; a second step of controlling a concentration of hydroxyl group on a. surface of the porous metal oxide semiconductor layer to be 0.01 groups/(nm)2 or more and 15 4.0 groups/(nm)2 or less; and a third step of supporting a dye in the porous metal oxide semiconductor layer. 10. The method for manufacturing a photoelectric 20 conversion device according to claim 9, wherein the concentration of hydroxyl group is controlled to be 0.01 groups/(nm)2 or more and 3.0 groups/(nm)2 or less. 11. The method for manufacturing a photoelectric 25 conversion device according to claim 9, wherein the concentration of hydroxyl group is controlled to be 0.02 groups/(nm)2 or more and 2.0 groups/(nm)2 or less. 12. The method for manufacturing a photoelectric 30 conversion. device according to claim 9, wherein the concentration of hydroxyl group is controlled to be 0.05 '7 6 groups/(nm)2 or more and 0.9 groups/(nm)2 or less. 13. The method for manufacturing a photoelectric conversion device according to claim 9, wherein the 5 concentration of adsorbed water on the surface of the porous metal oxide semiconductor layer is controlled to be 0.05 pieces/(nm)2 or more and 4.0 pieces/(nm)2 or less in the second step. 10 14. The method for manufacturing a photoelectric conversion device according to claim 9, wherein the concentration of adsorbed water is controlled to be 0.03 pieces/(nm)2 or more and 3.5 pieces/(nm)2 or less. 15. The method for manufacturing a photoelectric conversion device according to claim 9, wherein the concentration of adsorbed water is controlled to be 0.07 pieces/(nm)2 or more and 2.5 pieces/(nm)2 or less. 20 16. The method for manufacturing a photoelectric conversion device according to claim 9, wherein the concentration of adsorbed water is controlled to be 0.2 pieces/(nm)2 or more and 2.0 pieces/(nm)2 or less. 25 17. The method for manufacturing a photoelectric conversion device according to claim 9, wherein the concentration of hydroxyl group is controlled by performing, in the second step, at least one of a plasma treatment, a UV irradiation treatment, and a heat 30 treatment on the surface of the porous metal oxide semiconductor layer. 77 18. The method for manufacturing a photoelectric conversion device according to claim 17, wherein the plasma treatment is performed under an oxidizing atmosphere. 19. The method for manufacturing a photoelectric conversion device according to claim 17, wherein the plasma treatment is performed by using one of parallel plate plasma, barrel plasma, microwave plasma, ECR plasma, helicon wave plasma, hollow cathode discharge plasma, surface wave plasma, and are jet plasma.