FIELD OF INVENTION
[0002] The invention disclosed herein relates, in general, to a method of manufacturing organic photovoltaic devices. More specifically, the present invention relates to a method of manufacturing an organic photovoltaic device using high-throughput processes.
BACKGROUND
[0003] An organic photovoltaic device converts solar energy into electrical energy due to the presence of one or more organic photoactive layers, for example, layers made of polyphenylene vinylene, copper phthalocyanine, carbon fullerenes or fullerene derivatives. The organic photoactive layer may be a nano-morphological mixture of electron donor polymers and electron acceptor materials (like materials mentioned above) forming heterojunction. The organic photoactive layers are capable of generating excitons, i.e., bound electron-hole pairs. Solar radiation gets absorbed by electron donor materials and generates excitons. These excitons get diffused through photoactive material till interface of the electron donor and acceptor. At this interface, bound electron-hole pairs get separated into free charge carriers as electrons and holes. Electrically conducting layers are provided on both sides of the organic photoactive layers to collect these charge carriers and utilize them in external electric circuits in the form of current.
[0004] Generally, an organic photovoltaic device has a relatively low efficiency as compared to an inorganic photovoltaic device, e.g., a silicon-doped solar cell. Further, a current density for the organic photovoltaic device is low as compared to the current density for the inorganic photovoltaic device. Therefore, to obtain a reasonable voltage and current output, the motivation and efforts are to manufacture the organic photovoltaic device in a large size. This requires using a large substrate and depositing the required photoactive and electrically conducting layers on it. Theoretically, using a large substrate appears attractive, because more area can be processed in one go. This may, theoretically, reduce the tact time of the equipments and therefore reduces the overall cost of the product i.e. equipment cost per unit of power get reduced.
[0005] However, the organic photovoltaic devices of large area substrates are of a fixed output and may not be directly usable in some or more applications, such as, mobile chargers, solar lantern, calculators, MP3 players and other similar applications. These large area substrates are, thus, further cut/divided into smaller area for ease of handling and as per the requirements of the application. It is very similar to top-down approach. The division of large area devices into smaller area leads to additional area losses as well as reduced yield.
[0006] Moreover, there are varieties of limitations associated with manufacturing processes involving large substrates. Firstly, uniformity of the deposited layers may not be maintained over the large substrates. Secondly, depositing the layers on the large substrates is prone to defects, like, pinholes and non-homogeneity of the layer. Thirdly, handling large substrates requires precise movements that in turn need significant time. Further, to obtain desired electricity from the organic photovoltaic devices of large sizes, it may be needed to convert them into an
arrangement of multiple smaller organic photovoltaic devices that are connected using series or parallel connections. For this purpose, significant scribing of the deposited layers may be required, which in turn requires significant time. Additionally, equipments used for processing the large substrates are not standard; therefore customized equipments are required for processing the large substrates. Therefore, a capital cost of a manufacturing facility for processing the large substrates and corresponding organic photovoltaic devices is also significantly high.
[0007] All the above mentioned limitations may result in the organic photovoltaic devices being costly, less efficient and of poor-quality. Further, the manufacturing facility may also have a sub-optimum tact time, and therefore, a low throughput or yield.
[0008] There is, therefore, a need for a method of mass manufacturing an organic photovoltaic device, which overcomes some or all of the limitations identified above like high costs, low yield, slow throughput, non standard processing equipments, uniformity, non-homogeneity.
BRIEF DESCRIPTION OF FIGURES
[0009] The features of the present invention, which are believed to be novel, are set forth with particularity in the appended claims. The invention may best be understood by reference to the following description, taken in conjunction with the accompanying drawings. These drawings and the associated description are provided to illustrate some embodiments of the invention, and not to limit the scope of the invention.
[0010] FIG. 1 is a flow chart describing a method of manufacturing an organic photovoltaic device, in accordance with an embodiment of the present invention;
[0011] FIG. 2 is a flow chart describing a method of manufacturing the organic photovoltaic device, in accordance with another embodiment of the present invention;
[0012] FIG. 3 is a flow chart describing a method for encapsulating an active substrate with an inactive substrate, in accordance with an exemplary embodiment of the present invention;
[0013] FIGs. 4a and 4b are diagrammatic illustrations of a first substrate deposited with one or more layers, in accordance with some embodiments of the present invention;
[0014] FIGs. 5a and 5b are diagrammatic illustrations of the first substrate and a second substrate deposited with corresponding one or more layers, in accordance with some embodiments of the present invention;
[0015] FIGs. 6a, 6b and 6c are diagrammatic illustrations of the active substrate at different steps of a method of manufacturing the organic photovoltaic device, in accordance with an embodiment of the present invention; and
[0016] FIG. 7 is a diagrammatic illustration of a real-life application of one or more organic photovoltaic devices connected with series or parallel connections, in accordance with an embodiment of the present invention.
[0017] Those with ordinary skill in the art will appreciate that the elements in the figures are illustrated for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated, relative to other elements, in order to improve the understanding of the present invention.
[0018] There may be additional structures described in the foregoing application that are not depicted on one of the described drawings. In the event such a structure is described, but not depicted in a drawing, the absence of such a drawing should not be considered as an omission of such design from the specification.
SUMMARY
[0019] The instant exemplary embodiments provide a method of manufacturing an organic photovoltaic device.
[0020] Some embodiments provide a method of manufacturing the organic photovoltaic device, which can be used for mass manufacturing.
[0021] Some embodiments provide a cost-effective method of manufacturing the organic photovoltaic device, which can be used for mass manufacturing.
[0022] Some embodiments provide a method of manufacturing the organic photovoltaic device, such that a capital investment for a manufacturing facility to implement the method is less.
[0023] Some embodiments provide a method of manufacturing the organic photovoltaic device that eliminates or reduces the limitations involved in manufacturing the organic photovoltaic device using a large substrate.
[0024] In some embodiments, a method of manufacturing an organic photovoltaic device of pre-defined surface area is provided. The method includes providing a first substrate that has a surface area substantially equal to said pre-defined surface area, which is not greater than 900 square centimeters. The method further involves depositing one or more organic material layers on said first substrate by using either a batch deposition-process or an in-line process. Thereafter, a first high-throughput deposition-processing is performed on said one or more organic material layers, such that said first high-throughput deposition-processing is substantially suitable for said pre-defined surface area.
[0025] Additionally, a second substrate of a surface area substantially equal to and not greater than said pre-defined surface area is provided, and a second high-throughput deposition-processing is performed on it. The second high-throughput deposition-processing is also substantially suitable for said pre-defined surface area.
[0026] The first substrate is then encapsulated or bonded with said second substrate to form said organic photovoltaic device. The organic photovoltaic device is capable of generating electricity without a subsequent cutting process.
[0027] In some embodiments, the method of manufacturing the organic photovoltaic device having a pre-defined surface area includes providing a first substrate that has a surface area substantially equal to said pre-defined surface area, which is not greater than 900 square centimeters. Then a high-throughput depositing of a hole-transport layer is performed on said first substrate, such that said high-throughput depositing of said hole-transport layer is suitable for said pre-defined surface area. Thereafter, a first organic photoactive layer is deposited on said hole-transport layer by using either a batch deposition-process or an in-line process.
[0028] Optionally, the method may include high-throughput depositing of a first electrically conducting layer on said first organic photoactive layer, such that said optional high-throughput depositing of said first electrically conducting layer is suitable for said pre-defined surface area. Further, the method may also include optionally depositing a second organic photoactive layer on said first electrically conducting layer such that said second organic photoactive layer is deposited by using a batch deposition-process or an in-line process.
[0029] Then, the method includes high-throughput scribing of said second organic photoactive layer, said first electrically conducting layer, said first organic photoactive layer and said hole-transport layer from the first substrate, followed by high-throughput depositing of a second electrically conducting layer, such that, said high-throughput depositing is suitable for said pre-defined surface area. Thereafter, said second electrically conducting layer is scribed using high-throughput scribing, thereby forming an active substrate.
[0030] Additionally, a second substrate of a surface area substantially equal to and not greater than said pre-defined surface area is provided, and a high-throughput depositing of a gas-absorbent layer is performed on it to form an inactive substrate. The high-throughput depositing of said gas-absorbent layer is also suitable for said pre-defined surface area.
[0031] Thereafter, said active substrate is encapsulated or bonded with said inactive substrate to form said organic photovoltaic device. The organic photovoltaic device is capable of generating electricity without a subsequent cutting process.
[0032] In some embodiments, each layer from said hole-transport layer, said first organic photoactive layer, said first electrically conducting layer, said second organic photoactive layer, said second electrically conducting layer and said gas-absorbent layer is deposited by using a high-throughput manufacturing process that is suitable for the pre-defined size, i.e., a small form factor. Some examples of the high-throughput manufacturing process include, but are not limited to, dip coating, spin coating, doctored blade processing, spray coating, screen printing, sputtering, electroforming, evaporation and an in-line process.
DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
[0033] Before describing the present invention in detail, it should be observed that the present invention utilizes a combination of method steps and apparatus components related to a method of manufacturing an organic solar cell. Accordingly the apparatus components and the method steps have been represented where appropriate by conventional symbols in the drawings, showing only specific details that are pertinent for an understanding of the present invention so as not to obscure the disclosure with details that will be readily apparent to those with ordinary skill in the art having the benefit of the description herein.
[0034] While the specification concludes with the claims defining the features of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the following description in conjunction with the drawings, in which like reference numerals are carried forward.
[0035] As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting but rather to provide an understandable description of the invention.
[0036] The terms "a" or "an", as used herein, are defined as one or more than one. The
term "another", as used herein, is defined as at least a second or more. The terms "including" and/or "having" as used herein, are defined as comprising (i.e. open transition). The term "coupled" or "operatively coupled" as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically.
[0037] Referring now to the drawings, FIG. 1 is a flow chart describing a method 100 of manufacturing an organic photovoltaic device, in accordance with an embodiment of the present invention. The organic photovoltaic device has a pre-defined surface area.
[0038] In the subsequent description of the method 100, reference will be made to FIGs. 3, 4a, 4b, 5a and 5b to elaborate on structural information pertaining to various embodiments of the organic photovoltaic device and the method 100.
[0039] For the purpose of this description, the method 100 is explained for manufacturing of an organic photovoltaic device 500a (Refer FIG. 5a). However, it will be readily apparent to those ordinarily skilled in the art that the method 100 can be used for manufacturing of an organic photovoltaic device 500b (Refer FIG. 5b) or another organic photovoltaic device having the layers of the organic photovoltaic device 500a along with one or more additional layers.
[0040] The method 100 is initiated at step 102. At step 104, a first substrate 402 is provided. A surface area of the first substrate 402 is substantially equal to the pre-defined surface area, which is not greater than 900 square centimeters. For example, the first substrate 402 can be a square substrate of dimensions not greater than 30 cm X 30 cm. The square substrate of dimensions substantially equal to and not greater than 30 cm X 30 cm, is a standard-sized substrate, and significant number of manufacturing processes and equipments are standardized and optimized for a substrate of this size or surface area. For example, processes like, dip coating, spin coating, doctored blade processing, spray coating, screen printing, sputtering, electroforming and evaporation are already standardized for such a size and the corresponding manufacturing equipments are available as standard equipments.
[0041] In accordance with this invention, the first substrate 402 can be of any shape as long as the surface area of the first substrate 402 is substantially equal to but not greater than 900 square centimeters. For example, in one embodiment the first substrate 402 can be circular in shape, however, in another embodiment, the shape of the first substrate 402 can be, but is not limited to, polygonal, annular or elliptical.
[0042] In one embodiment, the first substrate 402 may include a glass substrate coated with an electrically conducting layer or an electrically conducting grid. Examples of the electrically conducting layer include, but are not limited to, a transparent conducting oxide (TCO), like, Indium Tin Oxide (ITO), Fluorine doped Tin Oxide (FTO), and Aluminum doped Zinc Oxide or a Carbon Nanotube Layer. Examples of the electrically conducting grid may include, but are not limited to, grids made from Aluminum, Copper, Gold, Silver, Polysilicon and a Silicide. In other embodiment, the first substrate 402 may include a transparent plastic substrate coated with an electrically conducting layer or an electrically conducting grid.
[0043] In an embodiment, the first substrate 402 is cleaned prior to performing subsequent steps of the method 100. For example, the first substrate 402 may be cleaned using an Ultrasonic or a Megasonic cleaning technique.
[0044] Thereafter, at step 106 one or more organic material layers 404 (Refer FIG. 4a) are deposited on the first substrate 402. In one embodiment, the one or more organic material layers 404 include an organic photoactive layer 410 (Refer FIG. 4b) that is responsible for generation of electricity in the organic photovoltaic device 500a. Photons present in the sun light received by the organic photoactive layer 410 generate excitons, i.e., bound electron-hole pairs, within the organic photoactive layer 410. These bound electron-hole pairs dissociate into free electrons and holes within the organic photoactive layer 410. The free electrons and holes act as the charge carriers that are responsible for generating electricity.
[0045] Examples of materials used for the organic photoactive layer 410, include, but are not limited to, polyphenylene vinylene, copper phthalocyanine, carbon fullerenes and fullerene derivatives such as Phenyl-C61 -butyric acid methyl ester, i.e., PCBM.
[0046] In another embodiment, the one or more organic material layers 404 may also include a hole-transport layer 408 (Refer FIG. 4b) in addition to the organic photoactive layer 410. The hole-transport layer 408 is deposited prior to depositing the organic photoactive layer 410. The hole-transport layer 408 is provided to enhance the transport of holes in the organic photovoltaic device 500a, thereby enhancing the efficiency of the organic photovoltaic device 500a.
[0047] Each of said one or more organic material layers, i.e., the hole-transport layer 408 and the organic photoactive layer 410 is deposited by using a batch deposition-process or an inline process.
[0048] In the batch process for depositing the organic photoactive layer 410, for example, an input set of multiple first substrates is provided. The organic photoactive layer 410 is deposited on each first substrate 402 of the multiple first substrates. An output of the batch process is a set of multiple deposited first substrates, i.e., a set of the multiple first substrates deposited with the organic photoactive layer 410. Thereafter, the multiple deposited first substrates are carried forward for further processing as per subsequent steps of the method 100.
[0049] In an in-line process, for example, the first substrate 402 is received as an input, deposited with the organic photoactive layer 410, and a deposited first substrate is provided as an output. Thereafter, the deposited first substrate is carried forward for further processing as per the subsequent steps of the method 100, while another first substrate is received as an input.
[0050] Examples of processes that can be implemented as the batch-deposition process and the in-line process for the step 106 include, but are not limited to, dip coating, spin coating, doctored blade processing, spray coating, screen printing, sputtering, electroforming and evaporation.
[0051] It will be readily apparent to those ordinarily skilled in the art that either of the batch process and the in-line process may be included in the method 100 without deviating from the scope of the invention. It will also be readily apparent to those ordinarily skilled in the art that the method 100 may be optimized for high-throughput by using either the batch process or the in-line process.
[0052] At step 108, a first high-throughput deposition-processing is performed on the one or more organic material layers 404. Referring to FIG. 4b, irrespective of a presence of the hole-transport layer 408, the first high-throughput deposition-processing is performed on the organic photoactive layer 410. define high-throughput, give it a number in one embodiment
[0053] The first high-throughput deposition-processing is performed using a manufacturing process which is suitable for the pre-defined surface area, i.e., the small form factor of substrates. Examples of the manufacturing process include, but are not limited to, dip coating, spin coating, doctored blade processing, spray coating, screen printing, sputtering, electroforming and evaporation.
[0054] Most of the high-throughput manufacturing process mentioned above have been optimized and standardized for the pre-defined size, i.e., for a surface area of substantially equal to but not greater than 900 square centimeters. However, there are limitations on using these processes for larger substrates, i.e., for substrates larger than the pre-defined size. They tend to generate outputs of sub-optimal quality or efficiency. For example, the uniformity of thickness of layers deposited by using spin coating may not be maintained over the large substrates. It may also induce defects, like, pinholes and non-homogeneity of the layers when used on large substrates.
[0055] Generally, a high-throughput manufacturing process is a process that is suitable for mass production, and therefore, produces a large quantity of products in a given time. In context of the method 100, when a method step is mentioned to have a high-throughput, for example, the step 108 of the first high-throughput deposition-processing, it refers that the method step is suitable to be performed for producing a bulk quantity of organic photovoltaic devices. Generally, the high-throughput process can be defined as a process capable of processing nearly 2.5 million products per year. In other words, the high-throughput process is a process that requires nearly 10 seconds for processing each product. Therefore, the first high-throughput deposition-processing substantially performs the deposition-processing on the one or more organic material layers 404 of the first substrate 402 in nearly 10 seconds.
[0056] Although, the high-throughput process is explained in reference to the first high-throughput deposition-processing, it will be readily apparent to those ordinarily skilled in the art that another method step in the method 100 that is mentioned to be a high-throughput process may be substantially similar to the high-throughput process in context of producing nearly 2.5 million products per year and requiring nearly 10 seconds for processing each product.
[0057] It will also be appreciated by a person skilled in the art that a production capacity of 2.5 million products per year and a tact time of 10 seconds are provided only as an example for illustrating the high-throughput process, and do not depict any limitation of the invention. The production capacity and the tact time of the high-throughput process, in accordance with the present invention, may be higher or lower than the ranges mentioned above.
[0058] In an embodiment, the first high-throughput deposition-processing may include depositing an electrically conducting layer 406 (Refer FIG. 4a) on the one or more organic material layers 404. In the embodiment when the one or more organic material layers 404 include only the organic photoactive layer 410, the electrically conducting layer 406 is deposited on the organic photoactive layer 410. Similarly, in the embodiment when the one or more organic material layers 404 include the hole-transport layer 408 and the organic photoactive layer 410, the electrically conducting layer 406 is deposited on the organic photoactive layer 410.
[0059] The electrically conducting layer 406 deposited on the organic photovoltaic layer 410 acts as one of the electrical contacts for connecting the organic photovoltaic device 500a to an external circuit requiring electricity or one or more organic photovoltaic devices. Generally, the
electrically conducting layer 406 deposited on the organic photovoltaic layer 410 acts as a cathode. The electrically conducting layer or the electrically conducting grid deposited on the glass substrate, of the first substrate 402, acts as another electrical contact for connecting the organic photovoltaic device 500a to the external circuit requiring electricity or to the one or more organic photovoltaic devices. Generally, the electrically conducting layer or the electrically conducting grid deposited on the glass substrate, of the first substrate 402, acts as an anode.
[0060] Examples of the electrically conducting layer 406 include, but are not limited to, a transparent conducting oxide (TCO), like, Indium Tin Oxide (ITO), Fluorine doped Tin Oxide (FTO), and Aluminum doped Zinc Oxide or a Carbon Nanotube Layer.
[0061] At step 110, a second substrate 502 (Refer FIG. 5a) is provided having a surface area substantially equal to and not greater than the pre-defined surface area of less than 900 square centimeters, i.e., the small form factor. Examples of the material of the second substrate 502 include, but are not limited to, glass.
[0062] In an embodiment, the second substrate 502 is cleaned prior to performing subsequent steps of the method 100. For example, the second substrate 502 may be cleaned using an Ultrasonic or a Megasonic cleaning technique.
[0063] At step 112, a second high-throughput deposition-processing is performed on the second substrate 502. The second high-throughput deposition-processing is performed using a manufacturing process which is suitable for the pre-defined surface area, i.e., the small form factor of substrates. Examples of the manufacturing process include, but are not limited to, dip coating, spin coating, doctored blade processing, spray coating, screen printing, sputtering, electroforming and evaporation.
[0064] The second high-throughput deposition-processing may include high-throughput deposition a gas-absorbent layer 504 (Refer FIG. 5a). The gas-absorbent layer 504 is provided to absorb any gases that are released during the method 100 of manufacturing the organic photovoltaic device 500a and during a use of the organic photovoltaic device 500a. For example, the organic photovoltaic device 500a may undergo a curing process or exposure to heat and/or strong ultra-violet rays during the manufacturing in accordance with the method 100 (Refer description of step 114). This may result in a release of contaminating gases from one or more layers in the organic photovoltaic device 500a. The gas-absorbent layer 504 prevents contamination of the organic photovoltaic device 500a from the contaminating gases.
[0065] At step 114, the first substrate 402, which is deposited with one or more layers 404 and 406 as per the foregoing steps of the method 100, is encapsulated or bonded with the second substrate 502, which is deposited with the gas-absorbent layer 504. In the subsequent description of the method 100, the first substrate 402, which is deposited with the one or more layers 404 and 406, is referred to as an active substrate 400a. Similarly, the second substrate 502, which is deposited with the gas-absorbent layer 504, is referred to as an inactive substrate 505.

[0066] The active substrate 400a is so termed as it includes the one or more organic material layers 404 capable of generating electricity. Similarly, the inactive substrate 505 is so termed as it does not include a layer capable of generating electricity.
[0067] A process of encapsulation is explained with reference to a method 300 depicted by a flow chart in FIG. 3. The method 300 initiates at step 302, the inactive substrate 505 is taken at step 304 and a bonding glue 506 is dispensed on the inactive substrate 505. The bonding glue 506 is dispensed on a surface of the inactive substrate 505 that has the gas-absorbent layer 504. Thereafter, at step 306, the inactive substrate 505, dispensed with bonding glue 506 is positioned over the active substrate 400a. The gas-absorbent layer 504 may absorb any gases trapped between the active substrate 400a and the inactive substrate 505 during the step 306. Thereafter, at step 308, an exposure of ultra-violet radiation is provided to perform ultra-violet curing and complete the encapsulation of the active substrate 400a with the inactive substrate 505. The gas-absorbent layer 504 may absorb any gases released during the step 308. The encapsulation method terminates at step 310. Although, the method 300 is shown to include ultra-violet curing, it will be readily apparent to those ordinarily skilled in the art that other forms of curing may also be performed without deviating from the scope of the invention.
[0068] Thereafter, the method 100 of manufacturing the organic photovoltaic device 500a also terminates at step 116.
[0069] As per the foregoing description of steps involved in the method 100, the method 100 does not involve a cutting process. Absence of the cutting process makes the method 100 efficient. Additionally, since the cutting process is not involved, a size of the organic photovoltaic device 500a is substantially similar to a size of the first substrate 402 and/or the second substrate 502, i.e., an input substrate is similar in size to an output device.
[0070] Each of the steps involved in the method 100 may be performed by either a batch process or an inline process. Further, the each of the steps involved in the method 100 may be implemented in such a way that a tact time of the manufacturing facility used to implement the method 100 is optimum. In an exemplary scenario, a time corresponding to each of the method steps in method 100 is designed to be substantially same, thereby reducing a waiting time between each process and optimizing the tact time for the manufacturing facility.
[0071] In real life applications, one or more organic photovoltaic devices manufactured as per the method 100 may be connected by using series or parallel connections to obtain an arrangement that can produce electrical output as per a requirement. Additionally, the one or more organic photovoltaic devices may be connected by using series or parallel connections to obtain an optimum electrical output.
[0072] In an exemplary real life scenario, an electrical equipment with a voltage requirement of 14 volts needs to be run using solar energy. Further, in this exemplary scenario, the voltage output of the organic photovoltaic device can be 0.7 volts. Therefore, 20 such organic
photovoltaic devices can be connected in series to obtain the required output of 14 volts and run the electrical equipment with solar energy.
[0073] It will be readily apparent to those ordinarily skilled in the art that the one or more organic photovoltaic devices may also be connected with photovoltaic devices prepared from other methods in real life applications.
[0074] Referring now to FIG. 2, there is shown a flow chart describing a method 200 of manufacturing an organic photovoltaic device 500b (Refer FIG. 5), in accordance with another embodiment of the present invention. The organic photovoltaic device 500b has the pre-defined surface area, which is not greater than 900 square centimeters.
[0075] In the subsequent description of the method 200, reference will be made to FIGs. 3, 4a, 4b, 5a, 5b, 6a, 6b, 6c and 7 to elaborate on structural information pertaining to various embodiments of the organic photovoltaic device 500b and the method 200.
[0076] For the purpose of this description, the method 200 is explained for manufacturing of the organic photovoltaic device 500b (Refer FIG. 5b). However, it will be readily apparent to those ordinarily skilled in the art that the method 200 can be used for manufacturing another organic photovoltaic device having the layers of the organic photovoltaic device 500b along with one or more additional layers.
[0077] The method 200 is initiated at step 202. At step 204, the first substrate 402 (Refer FIG. 4b) is provided. A surface area of the first substrate 402 is substantially equal to the predefined surface area, which is not greater than 900 square centimeters. For example, the first substrate 402 can be a square substrate of dimensions not greater than 30 cm X 30 cm.
[0078] The first substrate 402 includes a glass substrate coated with an electrically conducting layer or an electrically conducting grid. Examples of the electrically conducting layer include, but are not limited to, a transparent conducting oxide (TCO), like, Indium Tin Oxide (ITO), Fluorine doped Tin Oxide (FTO), and Aluminum doped Zinc Oxide or a Carbon Nanotube Layer. Examples of the electrically conducting grid may include, but are not limited to, grids made from Aluminum, Copper, Gold, Silver, Polysilicon and a Silicide.
[0079] In an embodiment, the first substrate 402 is cleaned prior to performing subsequent steps of the method 200. For example, the first substrate 402 may be cleaned by using an Ultrasonic or a Megasonic cleaning technique.
[0080] Thereafter, at step 206 a high-throughput depositing of the hole-transport layer 408 is performed on the first substrate 402. The high-throughput depositing of the hole-transport layer 408 is performed using a manufacturing process which is suitable for the pre-defined surface area, i.e., the small form factor of substrates. Examples of the manufacturing process include, but are not limited to, dip coating, spin coating, doctored blade processing, spray coating, screen printing, sputtering, electroforming and evaporation.
[0081] Generally, a high-throughput manufacturing process is a process that is suitable for mass production, and therefore, produces a large quantity of products in a given time. In context of the method 200, when a method step is mentioned to have a high-throughput, for example, the step 206 of high-throughput depositing of the hole-transport layer 408, it refers that the method step is suitable to be performed for producing a bulk quantity of the organic photovoltaic devices. Generally, the high-throughput process can be defined as a process capable of processing nearly 2.5 million products per year. In other words, the high-throughput process is a process that requires nearly 10 seconds for processing each product. Therefore, the high-throughput depositing of the hole-transport layer 408 substantially deposits the hole-transport layer 408 on the first substrate 402 in nearly 10 seconds.
[0082] Although, the high-throughput process is explained in reference to the high-throughput depositing of the hole-transport layer 408, it will be readily apparent to those ordinarily skilled in the art that another method step in the method 200 that is mentioned to be a high-throughput process may be substantially similar to the high-throughput process in context of producing nearly 2.5 million products per year and requiring nearly 10 seconds for processing each product.
[0083] It will also be appreciated by a person skilled in the art that a production capacity of 2.5 million products per year and a tact time of 10 seconds are provided only as an example for illustrating the high-throughput process, and do not depict any limitation of the invention. The production capacity and the tact time of the high-throughput process, in accordance with the present invention, may be higher or lower than the ranges mentioned above.
[0084] The hole-transport layer 408 is provided to enhance the transport of holes in the organic photovoltaic device 500b, thereby enhancing the efficiency of the organic photovoltaic device 500b.
[0085] Thereafter, at step 208, a first organic photoactive layer 410 is deposited on the hole-transport layer 408. The first organic photoactive layer 410 is responsible for generation of electricity in the organic photovoltaic device 500b. Photons present in the sun light received by the first organic photoactive layer 410 generate excitons, i.e., bound electron-hole pairs, within the first organic photoactive layer 410. These bound electron-hole pairs dissociate into free electrons and holes within the first organic photoactive layer 410. The free electrons and holes act as the charge carriers that are responsible for generating electricity.
[0086] Examples of the materials used for the first organic photoactive layer 410, include, but are not limited to, polyphenylene vinylene, copper phthalocyanine, carbon fullerenes and fullerene derivatives such as Phenyl-C61-butyric acid methyl ester, i.e., PCBM.
[0087] The first organic photoactive layer 410 is deposited by using a batch deposition-process or an in-line process.
[0088] In the batch process for depositing the first organic photoactive layer 410, for example, an input set of multiple first substrates is provided. The first organic photoactive layer 410 is deposited on each first substrate 402 of the multiple first substrates. An output of the batch process is a set of multiple deposited first substrates, i.e., a set of the multiple first substrates deposited with the first organic photoactive layer 410. Thereafter, the multiple deposited first substrates are carried forward for further processing as per subsequent steps of the method 200.
[0089] In an in-line process, for example, the first substrate 402 is received as an input, deposited with the first organic photoactive layer 410, and a deposited first substrate is provided as an output. Thereafter, the deposited first substrate is carried forward for further processing as per the subsequent steps of the method 200, while another first substrate is received as an input.
[0090] Examples of processes that can be implemented as the batch-deposition process and the in-line process for the step 208 include, but are not limited to, dip coating, spin coating, doctored blade processing, spray coating, screen printing, sputtering, electroforming and evaporation.
[0091] It will be readily apparent to those ordinarily skilled in the art that either of the batch process and the in-line process may be included in the method 200 without deviating from the scope of the invention. It will also be readily apparent to those ordinarily skilled in the art that the method 200 may be optimized for high-throughput by using either the batch process or the in-line process.
[0092] Thereafter at step 210, an optional high-throughput depositing of a first electrically conducting layer 412 on said first organic photoactive layer 410 is performed. The first electrically conducting layer 412 is performed using a manufacturing process which is suitable for the pre-defined surface area, i.e., the small form factor of substrates. Examples of the manufacturing process include, but are not limited to, dip coating, spin coating, doctored blade processing, spray coating, screen printing, sputtering, electroforming and evaporation.
[0093] Thereafter, at step 212, a second organic photoactive layer 414 is optionally deposited on the first electrically conducting layer 412. The second organic photoactive layer 414 is also capable of converting solar energy in the form of light into electricity.
[0094] Further, the second organic photoactive layer 414 is also deposited by using a batch deposition-process or an in-line process.
[0095] As mentioned above and as depicted by the dashed box 213 in the method 200, the step 210 and the step 212 are optional. It will be readily apparent to those ordinarily skilled in the art that an organic photoactive device can be manufactured by omitting the step 210 and the step 212 from the method 200 without deviating from the scope of the present invention.
[0096] Performing the step 210 and the step 212 may have additional benefits as explained in conjunction with step 218.
[0097] For the purpose of this description, the subsequent steps of the method 200 are explained considering the presence of the step 210, the step 212 and the corresponding layers, i.e., the first electrically conducting layer 412 and the second organic photoactive layer 414.
[0098] Thereafter, at step 214, the second organic photoactive layer 414, the first electrically conducting layer 412, the first organic photoactive layer 410 and the hole-transport layer 408 are scribed from the first substrate 402 using a high-throughput method.
[0099] Referring to FIG. 6a, the high-throughput scribing of the second organic photoactive layer 414, the first electrically conducting layer 412, the first organic photoactive layer 410 and the hole-transport layer 408 forms strips 602a, 602b, 602c, 602d, 602e and 602f on the first substrate 402.
[00100] Thereafter, at step 216, a high-throughput depositing of a second electrically conducting layer 416 is performed on the scribed second organic photoactive layer 414 by using a manufacturing process which is suitable for the pre-defined surface area, i.e., the small form factor of substrates (Refer FIG. 6b). Examples of the manufacturing process include, but are not limited to, dip coating, spin coating, doctored blade processing, spray coating, screen printing, sputtering, electroforming and evaporation.
[00101] Thereafter, at step 218, the second electrically conducting layer 416 is scribed from the first substrate 402 using another high-throughput method, thereby forming an active substrate 600c (Refer FIG. 6c).
[00102] Referring to FIG. 6c, the high-throughput scribing of the second electrically conducting layer 416 forms strips 604a, 604b, 604c, 604d, 604e and 604f on the first substrate 402 and also connects the strips 604a, 604b, 604c, 604d, 604e and 604f in series, to form the active substrate 600c.
[00103] Each strip of the strips 604a, 604b, 604c, 604d, 604e and 604f has all the layers deposited on the first substrate 402, therefore, the each strip can act as two power-generating portions connected in series. A first power-generating portion formed between the electrically conducting layer or the electrically conducting grid deposited on the first substrate 402 and the first electrically conducting layer 412. A second power-generating portion formed between the first electrically conducting layer 412 and the second electrically conducting layer 416. The first power-generating portion and the second power-generating portion connected in series due to a common electrically conducting layer, i.e., the first electrically conducting layer 412. As a result, presence of the step 210 and the step 212 in the method 200 may help in increasing an efficiency and an electrical output of the organic photovoltaic device 500b by increasing a number of the power generating portions.
[00104] A strip voltage across the electrically conducting layer or the electrically conducting grid of the first substrate 402 and the second electrically conducting layer 416 is substantially similar for the each strip. For example, in a hypothetical scenario, the strip voltage can be 0.7
volts. When the strips 604a, 604b, 604c, 604d, 604e and 604f are connected in series at the step 218 to form the active substrate 600c, a combined voltage of the active substrate 600c is substantially equivalent to an addition of the strip voltages of all the strips 604a, 604b, 604c, 604d, 604e and 604f, i.e., 0.7 X6 = 4.2 volts.
[00105] At step 220, a second substrate 502 is provided having a surface area substantially equal to and not greater than the pre-defined surface area of less than 900 square centimeters, i.e., the small form factor. Examples of the material of the second substrate include, but are not limited to, glass.
[00106] In an embodiment, the second substrate 502 is cleaned prior to performing subsequent steps of the method 100. For example, the second substrate 502 may be cleaned using an Ultrasonic or a Megasonic cleaning technique.
[00107] At step 222, a high-throughput depositing of a gas-absorbent layer 504 is performed on the second substrate 502, thereby forming an inactive substrate 507. The high-throughput depositing of the gas-absorbent layer 504 is performed using a manufacturing process which is suitable for the pre-defined surface area, i.e., the small form factor of substrates. Examples of the manufacturing process include, but are not limited to, dip coating, spin coating, doctored blade processing, spray coating, screen printing, sputtering, electroforming and evaporation.
[00108] The gas-absorbent layer 504 is provided to absorb any gases that are released during the method 200 of manufacturing the organic photovoltaic device 500b and during a use of the organic photovoltaic device 500b. For example, the organic photovoltaic device 500b may undergo a curing process or exposure to heat and/or strong ultra-violet rays during the manufacturing in accordance with the method 200. This may result in release of contaminating gases from one or more layers in the organic photovoltaic device 500b. The gas-absorbent layer 504 prevents contamination of the organic photovoltaic device 500b from the contaminating gases.
[00109] At step 224, the active substrate 600c is encapsulated or bonded with the inactive substrate 507. The method of encapsulation is similar to the method 300 explained with reference to FIG. 3 in conjunction with the foregoing description of FIG. 1.
[00110] Thereafter, the method 200 of manufacturing the organic photovoltaic device 500b terminates at step 226.
[00111] As per the foregoing description of steps involved in the method 100, the method 100 does not involve a cutting process. Absence of the cutting process makes the method 100 efficient. Additionally, since the cutting process is not involved, a size of the organic photovoltaic device 500b is substantially similar to a size of the first substrate 402 and/or the second substrate 502, i.e., an input substrate is similar in size to an output device.
[00112] Each of the steps involved in the method 200 may be performed by either a batch process or an inline process. Further, the each of the steps involved in the method 200 may be
implemented in such a way that a tact time of the manufacturing facility used to implement the method 200 is optimum. In an exemplary scenario, a time corresponding to each of the method steps in method 200 is designed to be substantially same, thereby reducing a waiting time between each process and optimizing the tact time for the manufacturing facility.
[00113] Referring to FIG. 7, one or more organic photovoltaic devices 500b manufactured as per the method 200 may be connected by using series or parallel connections 702a, 702b and 702c to obtain an arrangement 700 that can produce an electrical output as per a requirement, for example, the requirement of an external circuit 704. Additionally, one or more organic photovoltaic devices 500b may be connected by using series or parallel connections 702a, 702b and 702c to obtain an optimum electrical output.
[00114] It will be readily apparent to those ordinarily skilled in the art that the one or more organic photovoltaic devices 500b may also be connected with photovoltaic devices prepared from other methods in real life applications.
[00115] Various embodiments, as described above, provide a method for manufacturing an organic photovoltaic device, which has several advantages. One of the several advantages of some embodiments of this method is that a quality of the organic photovoltaic devices manufactured using this method is good, since, manufacturing processes used for deposition of various layers are conventional and standardized processes that have been tried and tested to be suitable for the pre-defined size of substrates to which the invention is applicable, i.e., the small form factor. This implies that a uniformity of deposited layers is substantially acceptable as well as the deposited layers have no or lesser defects like, pinholes and non-homogeneity of the layer. Further, since the substrates and organic photovoltaic device in accordance with the present invention are smaller in size, they can be easily handled and processed. This saves significant time and makes the process efficient. Further, no cutting is involved in the method disclosed in the present invention, which also helps make the method efficient.
[00116] A setup cost or capital cost of a manufacturing facility for implementing the method disclosed in the present invention is significantly lesser as compared to the existing methods. All the processes used in the present invention are conventional and standardized processes, therefore, the corresponding equipments are also standard and conventional and hence less expensive. Additionally, since the substrates and the organic photovoltaic device in accordance with the method of the present invention are of small form factor, the manufacturing equipment required is also correspondingly smaller in size, therefore, less expensive.
[00117] The method according to the present invention has another advantage that it enables mass production with high-throughput and yield since all the layers can be deposited by using high-throughput processes.
[00118] As described above, the capital cost for the manufacturing facility is less. Therefore, a cost of the organic photovoltaic device is also less. At the same time, an efficiency and quality
of the organic photovoltaic device is better. Therefore, another advantage of implementing the method according to the present invention is significantly low cost per unit of power produced.
[00119] While the invention has been disclosed in connection with the preferred embodiments shown and described in detail, various modifications and improvements thereon will become readily apparent to those ordinarily skilled in the art. Accordingly, the spirit and scope of the present invention is not to be limited by the foregoing examples, but is to be understood in the broadest sense allowable by law.
[00120] All documents referenced herein are hereby incorporated by reference.

CLAIMS
What is claimed is:
1. A method of manufacturing an organic photovoltaic device, the organic photovoltaic
device having a pre-defined surface area, the method comprising:
providing a first substrate, wherein a surface area of said first substrate is substantially equal to said pre-defined surface area, further wherein said pre-defined surface area is not greater than 900 square centimetres;
depositing one or more organic material layers on said first substrate, wherein each of said one or more organic material layers is deposited by using either a batch deposition-process or an in-line process;
first high-throughput deposition-processing on said one or more organic material layers, wherein said first high-throughput deposition-processing being substantially suitable for said pre-defined surface area;
providing a second substrate, wherein a surface area of said second substrate is substantially equal to and not greater than said pre-defined surface area;
second high-throughput deposition-processing on said second substrate, wherein said second high-throughput deposition-processing being substantially suitable for said predefined surface area; and
encapsulating or bonding said first substrate with said second substrate to form said organic photovoltaic device, wherein said organic photovoltaic device is a product itself, further wherein said device does not require a subsequent cutting process to achieve said pre-defined size of said organic photovoltaic device.
2. The method as recited in claim 1, wherein depositing said one or more organic material
layers on said first substrate comprises depositing a first organic photoactive layer on said first
substrate.
3. The method as recited in claim 2, wherein depositing said one or more organic material layers on said first substrate further comprises depositing at least one of a hole-transport layer, an electrically conducting layer and a second organic photoactive layer.
4. The method as recited in claim 1, wherein said first substrate comprises a glass substrate and at least one of a transparent conducting coating and a conducting grid.
5. The method as recited in claim 1, wherein said method is conventionally optimized for an optimum production rate with an optimum tact time.
6. The method as recited in claim 1, wherein said first high-throughput deposition-processing on said one or more organic material layers comprises high-throughput depositing of an electrically conducting layer.
7. The method as recited in claim 1, wherein said first high-throughput deposition-processing comprises at least one of dip coating, spin coating, doctored blade processing, spray coating, screen printing, sputtering, electroforming, evaporation and an in-line process.
8. The method as recited in claim 1, wherein said second high-throughput deposition-processing comprises at least one of dip coating, spin coating, doctored blade processing, spray coating, screen printing, sputtering, electroforming, evaporation and an in-line process.
9. The method as recited in claim 1, wherein said first high-throughput deposition-processing comprises either a batch deposition-processing or an in-line processing.
10. The method as recited in claim 1, wherein said second high-throughput deposition-processing comprises either a batch deposition-processing or an in-line processing.
11. The method as recited in claim 1 further comprising connecting one or more organic photovoltaic devices in at least one of parallel and series connections, whereby optimizing an electrical output from said one or more organic photovoltaic devices.
12. A method of manufacturing an organic photovoltaic device, the organic photovoltaic device having a pre-defined surface area, the method comprising:
providing a first substrate, wherein a surface area of said first substrate is substantially equal to said pre-defined surface area, further wherein said pre-defined surface area is not greater than 900 square centimetres;
high-throughput depositing of a hole-transport layer on said first substrate, wherein said high-throughput depositing of said hole-transport layer being suitable for said predefined surface area;
depositing a first organic photoactive layer on said hole-transport layer, wherein said first organic photoactive layer is deposited by using either a batch deposition-process or an in-line process;
optional high-throughput depositing of a first electrically conducting layer on said first organic photoactive layer, wherein said optional high-throughput depositing of said first electrically conducting layer being suitable for said pre-defined surface area;
optionally depositing a second organic photoactive layer on said first electrically conducting layer, wherein said second organic photoactive layer is deposited by using either a batch deposition-process or an in-line process;
high-throughput scribing of said second organic photoactive layer, said first electrically conducting layer, said first organic photoactive layer and said hole-transport layer from the first substrate;
high-throughput depositing of a second electrically conducting layer on said scribed second organic photoactive layer, wherein said high-throughput depositing of said second electrically conducting layer being suitable for said pre-defined surface area;
high-throughput scribing of said second electrically conducting layer from said first substrate, whereby forming an active substrate;
providing a second substrate, wherein a surface area of said second substrate is substantially equal to and not greater than said pre-defined surface area;
high-throughput depositing of a gas-absorbent layer on said second substrate, whereby forming an inactive substrate, wherein said high-throughput depositing of said gas-absorbent layer being suitable for said pre-defined surface area; and
encapsulating or bonding said active substrate with said inactive substrate to form said organic photovoltaic device, wherein said organic photovoltaic device is a product itself, further wherein said device does not require a subsequent cutting process to achieve said pre-defined size of said organic photovoltaic device.
13. The method as recited in claim 12, wherein said first substrate comprises a glass substrate and at least one of a transparent conducting coating and a conducting grid.
14. The method as recited in claim 12, wherein said method is conventionally optimized for an optimum production rate with an optimum tact time.
15. The method as recited in claim 12, wherein said high-throughput depositing of said hole-transport layer comprises dip coating, spin coating, doctored blade processing, spray coating, screen printing, sputtering, electroforming, evaporation and an in-line process.
16. The method as recited in claim 12, wherein said optional high-throughput depositing of said first electrically conducting layer comprises dip coating, spin coating, doctored blade processing, spray coating, screen printing, sputtering, electroforming, evaporation and an in-line process.
17. The method as recited in claim 12, wherein said high-throughput depositing of said second electrically conducting layer comprises dip coating, spin coating, doctored blade processing, spray coating, screen printing, sputtering, electroforming, evaporation and an in-line process.
18. The method as recited in claim 12, wherein said high-throughput depositing of said gas-absorbent layer comprises dip coating, spin coating, doctored blade processing, spray coating, screen printing, sputtering, electroforming, evaporation and an in-line process.
19. The method as recited in claim 12, wherein said high-throughput depositing of said hole-transport layer comprises either a batch deposition-processing or an in-line process.
20. The method as recited in claim 12, wherein said optional high-throughput depositing of said first electrically conducting layer comprises either a batch deposition-processing or an inline process.
21. The method as recited in claim 12, wherein said high-throughput depositing of said second electrically conducting layer comprises either a batch deposition-processing or an in-line process.
22. The method as recited in claim 12, wherein said high-throughput depositing of said gas-absorbent layer comprises either a batch deposition-processing or an in-line process.