SPACE OPTIMIZATION IN SPIN-COATED ORGANIC PHOTOACTIVE CELLS
BACKGROUND
The present invention relates, in general, to organic photoactive cells.
Organic photoactive cells have emerged as an alternative to silicon-based photoactive cells, and have a potential to provide a cheap source of energy. However, conventional organic photoactive cells suffer from several disadvantages.
FIG. 1 (Prior Art) depicts a top view of a typical spin-coated organic photoactive cell 100. Spin-coated organic photoactive cell 100 includes a square substrate 102 on which various cell layers 104 are fomned. Cell layers 104 may, for example, include a first electrode, a hole-transport layer, a photoactive layer and a second electrode. FIG. 2 (Prior Art) depicts a top view of a typical spin-coated organic photoactive module 200 formed by arranging a plurality of spin-coated organic photoactive cells lOOa-IOOp (similar to spin-coated organic photoactive cell 100) over a panel 202. As materials used in various cell layers 104 are typically formed by spin-coating, the corners of substrate 102 are not filled properly. This leads to inefficient utilization of the materials, the substrate area and the panel area.
In addition, a typical method of manufacturing spin-coated organic photoactive cell 100 involves masking the first electrode partially, forming subsequent layers thereon, and etching the masked first electrode to draw electrical contacts. This leads to formation of non-unifonn cell layers 104, and makes the manufacturing method complex, time-consuming, and expensive.
In light of the foregoing discussion, there is a need for a spin-coated organic photoactive module including a plurality of spin-coated organic

photoactive cells that are capable of efficiently utilizing materials, substrate area and panel area, are suitable for mass manufacturing, and have lower cost, compared to conventional spin-coated organic photoactive cells.
SUMMARY
An object of the present invention is to provide a spin-coated organic photoactive module having improved packaging efficiency.
Another object of the present invention is to provide a spin-coated organic photoactive cell that is capable of efficiently utilizing materials, substrate area and panel area, compared to conventional spin-coated organic photoactive cells.
Yet another object of the present invention is to provide a spin-coated organic photoactive cell that is suitable for mass manufacturing, and has lower cost, compared to conventional spin-coated organic photoactive cells.
Embodiments of the present invention provide a spin-coated organic photoactive module having improved packaging efficiency, and a method of manufacturing the spin-coated organic photoactive module. The spin-coated organic photoactive module includes a panel for providing support, and a plurality of spin-coated organic photoactive cells arranged over the panel. The spin-coated organic photoactive cells are connected electrically in a predefined manner. Each spin-coated organic photoactive cell includes a substrate having a symmetrical polygonal shape, a first electrode fonned over the substrate, a spin-coated hole-transport layer formed over the first electrode, a spin-coated photoactive layer formed over the spin-coated hole-transport layer, and a second electrode formed over the spin-coated photoactive layer. The symmetrical polygonal shape has more than four sides. The symmetrical polygonal shape enables optimal formation of the spin-coated hole-transport layer and the spin-coated photoactive layer. In addition, the symmetrical polygonal shape enables

improved packaging efficiency of the spin-coated organic photoactive cells in the spin-coated organic photoactive module.
In accordance with an embodiment of the present invention, the symmetrical polygonal shape is a hexagonal shape. The hexagonal shape enables optimal usage of one or more materials used in the formation of the spin-coated hole-transport layer and the spin-coated photoactive layer, and optimal usage of the area of the substrate.
In accordance with another embodiment of the present invention, the symmetrical polygonal shape is a circular shape. The circular shape enables optimal usage of one or more materials used in the formation of the spin-coated hole-transport layer and the spin-coated photoactive layer, and optimal usage of the area of the substrate.
In accordance with an embodiment of the present invention, the first electrode is formed in a first region beyond a first radius from a centre of the substrate, and the spin-coated hole-transport layer, the spin-coated photoactive layer and the second electrode are formed in a second region beyond a second radius from the centre of the substrate. The first radius may, for example, be smaller than the second radius. Accordingly, a portion of the first electrode, between the first radius and the second radius, is not covered with the spin-coated hole-transport layer, the spin-coated photoactive layer and the second electrode. This portion of the first electrode may be used to draw at least one electrical connector, so as to avoid shadow losses.
BRIEF DESCRIPTION OF DRAWINGS
Embodiments of the present invention will hereinafter be described in conjunction with the appended drawings provided to illustrate and not to limit the

scope of the claims, wherein like designations denote like elements, and In which:
FIG. 1 (Prior Art) depicts a top view of a spin-coated organic photoactive cell;
FIG. 2 (Prior Art) depicts a top view of a spin-coated organic photoactive module;
FIG. 3 depicts a top view of a spin-coated organic photoactive cell, in accordance
with an embodiment of the present invention;
FIG. 4 depicts a top view of a spin-coated organic photoactive module, in
accordance with an embodiment of the present invention;
FIGs. 5A and 5B depict a top view and a front view of a spin-coated organic
photoactive cell, respectively, in accordance with another embodiment of the
present invention;
FIG. 6 depicts a top view of a spin-coated organic photoactive module, in
accordance with another embodiment of the present invention;
FIG. 7 depicts various layers of a spin-coated organic photoactive cell, in
accordance with an embodiment of the present invention;
FIG. 8 depicts a system for manufacturing a spin-coated organic photoactive
module, in accordance with an embodiment of the present invention; and
FIG. 9 depicts a method of manufacturing a spin-coated organic photoactive
module, in accordance with an embodiment of the present invention,
DETAILED DESCRIPTION
Various embodiments of the present invention provide a spin-coated organic photoactive module having improved packaging efficiency, and a method of manufacturing the spin-coated organic photoactive module. The spin-coated organic photoactive module includes a panel, and a plurality of spin-coated organic photoactive cells arranged over the panel. A photoactive cell is defined as a cell whose functioning is based on activation of electrons due to incident photons. Each spin-coated organic photoactive cell includes a substrate having a symmetrical polygonal shape having more than four sides. The symmetrical

polygonal shape enables optimal formation of at least one layer of the spin-coated organic photoactive cell. In addition, the symmetrical polygonal shape enables improved packaging efficiency of the spin-coated organic photoactive cells in the spin-coated organic photoactive module.
Referring now to figures, FIG. 3 depicts a top view of a spin-coated organic photoactive cell 300, in accordance with an embodiment of the present invention. Spin-coated organic photoactive cell 300 includes a substrate 302 having a regular hexagonal shape. A regular polygon is defined as a polygon which is equiangular and equilateral. Spin-coated organic photoactive cell 300 includes a first electrode formed over substrate 302, a spin-coated hole-transport layer formed over the first electrode, a spin-coated photoactive layer formed over the spin-coated hole-transport layer, and a second electrode formed over the spin-coated photoactive layer.
With reference to FIG. 3, the spin-coated hole-transport layer and the spin-coated photoactive layer are fonned in a circular shape by spin-coating, and have been shown as cell layers 304. Details of the first electrode, the spin-coated hole-transport layer, the spin-coated photoactive layer, and the second electrode have been provided in conjunction with FIG. 7.
The regular hexagonal shape of substrate 302 enables formation of the spin-coated hole-transport layer and the spin-coated photoactive layer of a substantially unifomi thickness by virtue of centrifugal force. Consequently, the regular hexagonal shape enables optimal formation of the spin-coated hole-transport layer and the spin-coated photoactive layer. In addition, the regular hexagonal shape enables optimal usage of one or more materials used in the fonnation of the spin-coated hole-transport layer and the spin-coated photoactive layer, and optimal usage of the area of substrate 302.

In accordance with an additional embodiment of the present invention, the first electrode is formed In a first region beyond a first radius from a centre of substrate 302, and the spin-coated hole-transport layer, the spin-coated photoactive layer and the second electrode are fomied in a second region beyond a second radius from the centre of substrate 302. In case when the first radius is smaller than the second radius, a portion of the first electrode, between the first radius and the second radius, is not covered with the spin-coated hole-transport layer, the spin-coated photoactive layer and the second electrode. Accordingly, this portion of the first electrode may be used to draw at least one electrical connector, so as to avoid any shadow losses.
In accordance with another additional embodiment of the present invention, substrate 302 may include a hole (not shown in FIG. 3) at the centre of substrate 302. The hole may, for example, facilitate proper holding of substrate 302 during spin-coating. In addition, one or more electrical connectors may be drawn from the hole, thereby avoiding any shadow losses.
In accordance with an embodiment of the present invention, spin-coated organic photoactive cell 300 also includes a covering member (not shown in FIG. 3). The covering member may, for example, be sealed with substrate 302, so as to encapsulate the first electrode, the spin-coated hole-transport layer, the spin-coated photoactive layer and the second electrode between substrate 302 and the covering member.
It is to be understood that the specific designation for spin-coated organic photoactive cell 300 and its various components is for the convenience of the reader and is not to be construed as limiting spin-coated organic photoactive cell 300 to a specific size, shape, type, or arrangement of its components. For example, substrate 302 may have any polygonal shape.

FIG. 4 depicts a top view of a spin-coated organic photoactive module 400, in accordance with an embodiment of the present invention. Spin-coated organic photoactive module 400 includes a panel 402 and a plurality of spin-coated organic photoactive cells, shown as spin-coated organic photoactive cells 300a-300q, arranged over panel 402. Spin-coated organic photoactive cells 300a-300q are hereinafter referred as spin-coated organic photoactive cells 300.
Panel 402 provides support to spin-coated organic photoactive cells 300. Panel 402 may, for example, be made of a metal like aluminum or a plastic.
Spin-coated organic photoactive cells 300 are connected electrically in a predefined manner. The predefined manner may, for example, be a series and/or parallel arrangement.
Each spin-coated organic photoactive cell of spin-coated organic photoactive cells 300 is substantially similar to spin-coated organic photoactive cell 300 depicted in FIG. 3.
The regular hexagonal shape of substrate 302 enables optimal usage of space covered by spin-coated organic photoactive cells 300 over panel 402, as depicted in FIG. 4. Consequently, the regular hexagonal shape enables improved packaging efficiency of spin-coated organic photoactive cells 300 in spin-coated organic photoactive module 400.
It is to be understood that the specific designation for spin-coated organic photoactive module 400 and its various components is for the convenience of the reader and is not to be construed as limiting spin-coated organic photoactive module 400 to a specific size, shape, type, or arrangement of its components.
FIGs. 5A and 5B depict a top view and a front view of a spin-coated organic photoactive cell 500, respectively, in accordance with another

embodiment of the present invention. Spin-coated organic photoactive cell 500 includes a substrate 502 having a circular shape, a first electrode formed over substrate 502, a spin-coated hole-transport layer formed over the first electrode, a spin-coated photoactive layer formed over the spin-coated hole-transport layer, and a second electrode fomied over the spin-coated photoactive layer.
With reference to FIGs. 5A and 5B, the spin-coated hole-transport layer and the spin-coated photoactive layer are formed in a circular shape by spin-coating, and have been shown as cell layers 504. Details of the first electrode, the spin-coated hole-transport layer, the spin-coated photoactive layer, and the second electrode have been provided in conjunction with FIG. 7.
The circular shape of substrate 502 enables formation of the spin-coated hole-transport layer and the spin-coated photoactive layer of a substantially unifomn thickness by virtue of centrifugal force. Consequently, the circular shape enables optimal formation of the spin-coated hole-transport layer and the spin-coated photoactive layer. In addition, the circular shape enables optimal usage of one or more materials used in the formation of the spin-coated hole-transport layer and the spin-coated photoactive layer, and optimal usage of the area of substrate 502.
In accordance with an additional embodiment of the present invention, the first electrode is formed in a first region beyond a first radius from a centre of substrate 502, and the spin-coated hole-transport layer, the spin-coated photoactive layer and the second electrode are formed in a second region beyond a second radius from the centre of substrate 502. In case when the first radius is smaller than the second radius, a portion of the first electrode, between the first radius and the second radius, is not covered with the spin-coated hole-transport layer, the spin-coated photoactive layer and the second electrode. Accordingly, this portion of the first electrode may be used to draw at least one electrical connector, so as to avoid any shadow losses.

In accordance with another additional embodiment of the present invention, substrate 502 may include a hole (not shown in FIGs. 5A and 5B) at the centre of substrate 502. The hole may, for example, facilitate proper holding of substrate 502 during spin-coating. In addition, one or more electrical connectors may be drawn from the hole, thereby avoiding any shadow losses.
In accordance with an embodiment of the present Invention, spin-coated organic photoactive cell 500 also includes a covering member (not shown in FIGs. 5A and 5B). The covering member may, for example, be sealed with substrate 502, so as to encapsulate the first electrode, the spin-coated hole-transport layer, the spin-coated photoactive layer and the second electrode between substrate 502 and the covering member.
It is to be understood that the specific designation for spin-coated organic photoactive cell 500 and its various components is for the convenience of the reader and is not to be construed as limiting spin-coated organic photoactive cell 500 to a specific size, shape, type, or arrangement of its components.
FIG. 6 depicts a top view of a spin-coated organic photoactive module 600, in accordance with another embodiment of the present Invention. Spin-coated organic photoactive module 600 includes a panel 602 and a plurality of spin-coated organic photoactive cells, shown as spin-coated organic photoactive cells 500a-500v, arranged over panel 602. Spin-coated organic photoactive cells 500a-500v are hereinafter referred as spin-coated organic photoactive cells 500.
Panel 602 provides support to spin-coated organic photoactive cells 500. Panel 602 may, for example, be made of a metal like aluminum or a plastic.

Spin-coated organic photoactive cells 500 are connected electrically in a predefined manner. The predefined manner may, for example, be a series and/or parallel arrangement.
Each spin-coated organic photoactive cell of spin-coated organic photoactive cells 500 is substantially similar to spin-coated organic photoactive cell 500 depicted in FIGs. 5A and 5B.
The circular shape of substrate 502 enables optimal usage of space covered by spin-coated organic photoactive cells 500 over panel 602, as depicted In FIG. 6. Consequently, the circular shape enables improved packaging efficiency of spin-coated organic photoactive cells 500 in spin-coated organic photoactive module 600.
It is to be understood that the specific designation for spin-coated organic photoactive module 600 and its various components is for the convenience of the reader and is not to be construed as limiting spin-coated organic photoactive module 600 to a specific size, shape, type, or arrangement of Its components.
Consider, for example, that a panel of a square shape is used to form a spin-coated organic photoactive module. The panel may, for example, have a length and breadth of 96 cm. The total area of the panel is 9216 cm^.
Case 1 - Square-shaped Substrate
Let us consider a plurality of spin-coated organic photoactive cells having a substrate having the shape of a square, as depicted in FIGs. 1 and 2 (Prior Art).
Side of the square = 8 cm
The area of a single square = 64 cm^
Therefore, the number of spin-coated organic photoactive cells that may cover the entire area of the panel = 9216/64 = 144

Various cell layers are formed by spin-coating over the substrate, and therefore, occupy a circular area over the substrate. The area covered by the cell layers over the substrate may be calculated as 3.14 x 4 x 4 = 50.24 cm^
The total area covered by the cell layers over the panel = 50.24 x 144 = 7235 cm^
The percentage of area utilized = 7235 * 100 / 9216 = 78.5 %
Case 2 - Hexagonal-shaped Substrate
Let us consider a plurality of spin-coated organic photoactive cells having a substrate of a regular hexagonal shape, as depicted in FIGs. 3 and 4.
Side of the regular hexagon = 4 cm
Diagonal of the regular hexagon - 8 cm
The area of a single regular hexagon = 41.57 cm^
The number of regular hexagons that may come in one row =16
The number of regular hexagons that may come in one column = 13
Therefore, the number of spin-coated organic photoactive cells that may cover the entire area of the panel = 16x13 = 208
Various cell layers are formed by spin-coating over the substrate, and therefore, occupy a circular area over the substrate. The area covered by the cell layers over the substrate may be calculated as 3.14 x 3.464 x 3.464 = 37.68 cm^
The total area covered by the cell layers over the panel = 37.68 x 208 = 7837 cm^
The percentage of area utilized = 7837 * 100 / 9216 = 85 %
Case 3 - Circular-shaped Substrate
Let us consider a plurality of spin-coated organic photoactive cells having a substrate of a circular shape, as depicted in FIGs. 5A-5B and 6.
Radius of the circle = 4 cm
The area of a single circle = 50.24 cm^
The number of circles that may come in one row =12
The number of circles that may come in one column = 13
11

Therefore, the number of spin-coated organic photoactive cells that may cover the entire area of the panel = 12x13 = 156
Various cell layers are formed by spin-coating over the substrate, and therefore, occupy the entire area of the substrate. Therefore, the area covered by the cell layers over the substrate = 50.24 cm^
The total area covered by the cell layers over the panel = 50.24 x 156 = 7837 cm=^
The percentage of area utilized = 7837 * 100 / 9216 = 85 %
On the basis of the above calculations, it may be concluded that the regular hexagonal shape (case 2) and the circular shape (case 3) enable optimal usage of the area of the substrate and the area of the panel, and enable improved packaging efficiency of the spin-coated organic photoactive cells in the spin-coated organic photoactive module.
FIG. 7 depicts various layers of a spin-coated organic photoactive cell 700, in accordance with an embodiment of the present invention. Spin-coated organic photoactive cell 700 includes a substrate 702 of a symmetrical polygonal shape, a first electrode 704 formed over substrate 702, a spin-coated hole-transport layer 706 formed over first electrode 704, a spin-coated photoactive layer 708 formed over spin-coated hole-transport layer 706, a second electrode 710 formed over spin-coated photoactive layer 708, and a covering member 712 placed over second electrode 710.
The symmetrical polygonal shape of substrate 702 is substantially similar to the shape of a symmetrical polygon having more than four sides. As described earlier, the symmetrical polygonal shape enables formation of spin-coated hole-transport layer 706 and spin-coated photoactive layer 708 of a substantially uniform thickness by virtue of centrifugal force. Consequently, the symmetrical polygonal shape enables optimal formation of spin-coated hole-transport layer

706 and spin-coated photoactive layer 708, and optimal usage of the area of substrate 702.
In accordance with an embodiment of the present invention, the symmetrical polygonal shape is a hexagonal shape. In accordance with another embodiment of the present invention, the symmetrical polygonal shape is a circular shape.
As described earlier, the symmetrical polygonal shape enables optimal usage of space covered by a plurality of spin-coated organic photoactive cells 700 over a panel.
In accordance with an embodiment of the present invention, substrate 702 is optically transparent, and electromagnetic radiation incident on spin-coated organic photoactive cell 700 passes through substrate 702 towards spin-coated photoactive layer 708. Substrate 702 may, for example, be made of an optically-transparent material that is tolerant to moisture, Ultra-Violet (UV) radiation, abrasion, and natural temperature variations. Examples of such optically-transparent materials include, but are not limited to, glass, plastics, polycarbonates, polymers, and acrylics. In addition, substrate 702 may be coated with an anti-reflective coating to reduce loss of incident electromagnetic radiation.
A first conductive material is used to fomi first electrode 704. The first conductive material may, for example, be a transparent conductive oxide, such as Indium Tin Oxide (ITO), Zinc Oxide, Aluminum-doped Zinc Oxide, and Fluorine-doped Tin Oxide (FTO). Alternatively, a suitable transparent conductive polymer may be used as the first conductive material.
First electrode 704 may, for example, be formed by spin-coating the first conductive material over substrate 702. Accordingly, the symmetrical polygonal shape of substrate 702 enables optimal usage of the first conductive material.

A hole-transport material is used to form spin-coated hole-transport layer 706 over first electrode 704. Spin-coated hole-transport layer 706 is formed by spin-coating the hole-transport material over first electrode 704. Accordingly, the symmetrical polygonal shape of substrate 702 enables optimal usage of the hole-transport material.
Spin-coated hole-transport layer 706 allows incident electromagnetic radiation to pass through towards spin-coated photoactive layer 708. In one example, spin-coated hole-transport layer 706 may be made of a hole-transport material that is optically transparent in a specific region of the incident electromagnetic radiation, for example, the visible spectrum and/or Infra-Red (IR) radiation.
Examples of the hole-transport material Include, but are not limited to, Poly(3,4-ethylenedioxythiophene) (PEDOT), Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate)(PEDOT:PSS).
In accordance with an embodiment of the present invention, the thickness of spin-coated hole-transport layer 706 is adjusted to allow proper transmission of incident electromagnetic radiation and transportation of charge carriers simultaneously. For example, the thickness of spin-coated hole-transport layer 706 may range from 30 nm to 150 nm.
A photoactive material is used to fom spin-coated photoactive layer 708 over spin-coated hole-transport layer 706. Spin-coated photoactive layer 708 is formed by spin-coating the photoactive material over spin-coated hole-transport layer 706. Accordingly, the symmetrical polygonal shape of substrate 702 enables optimal usage of the photoactive material.

In one example, the photoactive material may include an active polymer and a fullerene-based electron acceptor. An active polymer is an organic polymer that generates charge carriers upon being activated by incident electromagnetic radiation. In another example, the photoactive material may include a nano-particle-based electron acceptor, instead of a fullerene-based electron acceptor.
A second conductive material is used to form second electrode 710 over spin-coated photoactive layer 708. The second conductive material may, for example, be Aluminum. Silver, Calcium and Barium.
Second electrode 710 may, for example, be formed by spin-coating the second conductive material over spin-coated photoactive layer 708. Accordingly, the symmetrical polygonal shape of substrate 702 enables optimal usage of the second conductive material.
Covering member 712 is sealed with substrate 702, so as to encapsulate and protect first electrode 704, spin-coated hole-transport layer 706, spin-coated photoactive layer 708 and second electrode 710 from environmental damage. Covering member 712 may, for example, be a plastic cover.
In accordance with an alternative embodiment of the present invention, covering member 712 is optically transparent, and incident electromagnetic radiation passes through covering member 712 towards spin-coated photoactive layer 708. Accordingly, covering member 712 may, for example, made of an optically-transparent material, while substrate 702 may be made of a non-transparent material.
When electromagnetic radiation is incident over spin-coated photoactive layer 708, electron-hole pairs are created in spin-coated photoactive layer 708. The electromagnetic radiation may, for example, include IR radiation, visible spectrum, and UV radiation.

Electrons and holes are separated at an interface between spin-coated photoactive layer 708 and spin-coated hole-transport layer 706, thereby generating a voltage. When a load is connected across first electrode 704 and second electrode 710, the generated voltage drives current, thereby producing electricity.
It is to be understood that the specific designation for spin-coated organic photoactive cell 700 and its various components is for the convenience of the reader and is not to be construed as limiting spin-coated organic photoactive cell 700 to a specific size, shape, type, or arrangement of its components.
FIG. 8 depicts a system 800 for manufacturing a spin-coated organic photoactive module, in accordance with an embodiment of the present invention. System 800 includes a photoactive-cell manufacturing unit 802 that includes a substrate-obtaining unit 804, a first-electrode forming unit 806, a hole-transport-layer forming unit 808, a photoactive-layer forming unit 810, and a second-electrode forming unit 812. System 800 also includes arranging unit 814 and connecting unit 816.
Photoactive-cell manufacturing unit 802 manufactures a plurality of spin-coated organic photoactive cells. Each spin-coated organic photoactive cell is manufactured as explained below.
Substrate-obtaining unit 804 obtains a substrate of a symmetrical polygonal shape having more than four sides. In accordance with an embodiment of the present invention, the symmetrical polygonal shape is a hexagonal shape. In accordance with another embodiment of the present invention, the symmetrical polygonal shape is a circular shape. Substrate-obtaining unit 804 may, for example, mold a polymeric material to form a substrate of a desired shape.

The substrate may, for example, be made of an optically-transparent material that is tolerant to moisture, UV radiation, abrasion, and natural temperature variations. Examples of such optically-transparent materials include, but are not limited to, glass, plastics, polycarbonates, polymers, and acrylics.
First-electrode fonning unit 806 then forms a first electrode over the substrate. First-electrode forming unit 806 may, for example, spin-coat a first conductive material over the substrate. In another example, first-electrode forming unit 806 may sputter-deposit the first conductive material on the entire surface of the substrate.
The first conductive material may, for example, be a transparent conductive oxide, such as Indium Tin Oxide (ITO), Zinc Oxide, Aluminum-doped Zinc Oxide, and Fluorine-doped Tin Oxide (FTO). Alternatively, a suitable transparent conductive polymer may be used as the first conductive material.
Subsequently, hole-transport-layer forming unit 808 forms a spin-coated hole-transport layer over the first electrode, by spin-coating a hole-transport material over the first electrode.
Examples of the hole-transport material include, but are not limited to, Poly(3,4-ethylenedloxythiophene) (PEDOT), Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate)(PEDOT:PSS).
Thereafter, photoactive-layer forming unit 810 fonns a spin-coated photoactive layer over the spin-coated hole-transport layer, by spin-coating a photoactive material over the spin-coated hole-transport layer.
In one example, the photoactive material may include an active polymer and a fullerene-based electron acceptor. In another example, the photoactive

material may include a nano-particle-based electron acceptor, instead of a fullerene-based electron acceptor.
Second-electrode forming unit 812 then forms a second electrode over the spin-coated photoactive layer. Second-electrode forming unit 812 may, for example, spin-coat a second conductive material over the spin-coated photoactive layer. In another example, second-electrode forming unit 812 may sputter-deposit the second conductive material over the spin-coated photoactive layer.
The second conductive material may, for example, be Aluminum, Silver, Calcium and Barium.
The symmetrical polygonal shape of the substrate enables formation of the spin-coated hole-transport layer and the spin-coated photoactive layer of a substantially uniform thickness by virtue of centrifugal force. Consequently, the symmetrical polygonal shape enables optimal formation of the spin-coated hole-transport layer and the spin-coated photoactive layer. In addition, the symmetrical polygonal shape enables optimal usage of the hole-transport material and the photoactive material, and optimal usage of the area of the substrate.
In accordance with an embodiment of the present invention, system 800 also includes a pick-and-place unit for placing a covering member over the second electrode, and a sealing unit for sealing the covering member with the substrate.
In accordance with an additional embodiment of the present invention, the first electrode is formed in a first region beyond a first radius from a centre of the substrate, and the spin-coated hole-transport layer, the spin-coated photoactive layer and the second electrode are formed in a second region beyond a second

radius from the centre of the substrate. In case when the first radius is smaller than the second radius, a portion of the first electrode, between the first radius and the second radius, is not covered with the spin-coated hole-transport layer, the spin-coated photoactive layer and the second electrode. Accordingly, this portion of the first electrode may be used to draw at least one electrical connector.
In accordance with another additional embodiment of the present invention, the substrate may include a hole at its centre. The hole may, for example, facilitate proper holding of the substrate during spin-coating. In addition, one or more electrical connectors may be drawn from the hole.
Subsequently, arranging unit 814 arranges the spin-coated organic photoactive cells over a panel. In an embodiment of the present invention, the spin-coated organic photoactive cells are hexagonal in shape, as depicted in FIG. 3. Accordingly, the spin-coated organic photoactive cells are arranged over the panel, as depicted in FIG. 4. In another embodiment of the present invention, the spin-coated organic photoactive cells are circular in shape, as depicted in FIGs. 5A and 5B. Accordingly, the spin-coated organic photoactive cells are arranged over the panel, as depicted in FIG. 6.
The symmetrical polygonal shape of the substrate enables optimal usage of space covered by the spin-coated organic photoactive cells over the panel. Consequently, the symmetrical polygonal shape enables improved packaging efficiency of the spin-coated organic photoactive cells in the spin-coated organic photoactive module.
Connecting unit 816 connects the spin-coated organic photoactive cells electrically in a predefined manner. The predefined manner may, for example, be a series and/or parallel arrangement.

FIG. 8 is merely an example, which should not unduly limit the scope of the claims herein. For example, system 800 may include a cleaning unit for cleaning the substrate before the first electrode is formed.
FIG. 9 depicts a method of manufacturing a spin-coated organic photoactive module, in accordance with an embodiment of the present invention.
At step 902, a plurality of spin-coated organic photoactive cells is manufactured. Step 902 includes steps 904-912.
At step 904, a substrate of a symmetrical polygonal shape having more than four sides is obtained. In accordance with an embodiment of the present invention, the symmetrical polygonal shape is a hexagonal shape. In accordance with another embodiment of the present invention, the symmetrical polygonal shape is a circular shape. Step 904 may, for example, Include molding a polymeric material to form a substrate of a desired shape.
The substrate may, for example, be made of an optically-transparent material that is tolerant to moisture, UV radiation, abrasion, and natural temperature variations. Examples of such optically-transparent materials include, but are not limited to, glass, plastics, polycarbonates, polymers, and acrylics.
At step 906, a first electrode Is fomied over the substrate. Step 906 may, for example, include spin-coating a first conductive material over the substrate. In another example, step 906 may include sputter-depositing the first conductive material on the entire surface of the substrate.
The first conductive material may, for example, be a transparent conductive oxide, such as Indium Tin Oxide (ITO), Zinc Oxide, Aluminum-doped Zinc Oxide, and Fluorine-doped Tin Oxide (FTO). Alternatively, a suitable transparent conductive polymer may be used as the first conductive material.

Subsequently, at step 908, a spin-coated hole-transport layer is formed over the first electrode, by spin-coating a hole-transport material over the first electrode.
Examples of the hole-transport material include, but are not limited to, Poly(3,4-ethylenedioxythiophene) (PEDOT), Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate)(PEDOT:PSS).
Thereafter, at step 910, a spin-coated photoactive layer is formed over the spin-coated hole-transport layer, by spin-coating a photoactive material over the spin-coated hole-transport layer.
In one example, the photoactive material may include an active polymer and a fullerene-based electron acceptor. In another example, the photoactive material may include a nano-particle-based electron acceptor, instead of a fullerene-based electron acceptor.
At step 912, a second electrode is formed over the spin-coated photoactive layer. Step 912 may, for example, include spin-coating a second conductive material over the spin-coated photoactive layer. In another example, step 912 may include sputter-depositing the second conductive material over the spin-coated photoactive layer.
The second conductive material may, for example, be Aluminum, Silver, Calcium and Barium.
The symmetrical polygonal shape of the substrate enables fonnation of the spin-coated hole-transport layer and the spin-coated photoactive layer of a substantially uniform thickness by virtue of centrifugal force. Consequently, the symmetrical polygonal shape enables optimal formation of the spin-coated hole-

transport layer and the spin-coated photoactive layer. In addition, the symmetrical polygonal shape enables optimal usage of the hole-transport material and the photoactive material, and optimal usage of the area of the substrate.
In accordance with an embodiment of the present invention, a step of placing a covering member over the second electrode, and a step of sealing the covering member with the substrate may be performed.
In accordance with an additional embodiment of the present invention, the first electrode is fonned in a first region beyond a first radius from a centre of the substrate, and the spin-coated hole-transport layer, the spin-coated photoactive layer and the second electrode are formed in a second region beyond a second radius from the centre of the substrate. In case when the first radius is smaller than the second radius, a portion of the first electrode, between the first radius and the second radius, is not covered with the spin-coated hole-transport layer, the spin-coated photoactive layer and the second electrode. Accordingly, this portion of the first electrode may be used to draw at least one electrical connector.
In accordance with another additional embodiment of the present invention, the substrate may include a hole at its centre. The hole may, for example, facilitate proper holding of the substrate during spin-coating. In addition, one or more electrical connectors may be drawn from the hole.
At step 914, the spin-coated organic photoactive cells are arranged over a panel. In an embodiment of the present invention, the spin-coated organic photoactive cells are hexagonal in shape, as depicted in FIG. 3. Accordingly, the spin-coated organic photoactive cells are arranged over the panel, as depicted in FIG. 4. In another embodiment of the present invention, the spin-coated organic photoactive cells are circular in shape, as depicted in FIGs. 5A and 5B.

Accordingly, the spin-coated organic photoactive cells are arranged over the panel, as depicted in FIG. 6.
The symmetrical polygonal shape of the substrate enables optimal usage of space covered by the spin-coated organic photoactive cells over the panel. Consequently, the symmetrical polygonal shape enables improved packaging efficiency of the spin-coated organic photoactive cells in the spin-coated organic photoactive module.
At step 916, the spin-coated organic photoactive cells are connected electrically in a predefined manner. The predefined manner may, for example, be a series and/or parallel arrangement.
It should be noted here that steps 902-916 are only illustrative and other alternatives can also be provided where steps are added, one or more steps are removed, or one or more steps are provided in a different sequence without departing from the scope of the claims herein. For example, a step of cleaning the substrate may be performed before step 906.
Embodiments of the present invention provide a spin-coated organic photoactive module having improved packaging efficiency, and a manufacturing method and system thereof. The spin-coated organic photoactive module includes a plurality of spin-coated organic photoactive cells that include a substrate having a symmetrical polygonal shape.
The symmetrical polygonal shape of the substrate enables fomnation of a spin-coated hole-transport layer and a spin-coated photoactive layer of a substantially uniform thickness by virtue of centrifugal force. Consequently, the symmetrical polygonal shape enables optimal formation of the spin-coated hole-transport layer and the spin-coated photoactive layer.

The symmetrical polygonal shape also enables optimal usage of a hole-transport material and a photoactive material, and optimal usage of the area of the substrate. This, in turn, reduces the cost of manufacturing the spin-coated organic photoactive module.
In addition, the symmetrical polygonal shape enables improved packaging efficiency of the spin-coated organic photoactive cells in the spin-coated organic photoactive module.
Further, the manufacturing method does not require masking and etching of electrodes, and therefore, Is simple and easy to perform. This makes the spin-coated organic photoactive cells suitable for mass manufacturing.
Moreover, electrodes are drawn in a manner that shadow losses are avoided. This enhances the efficiency of the spin-coated organic photoactive module.
Furthermore, the spin-coated organic photoactive module can be used in various applications. For example, an array of spin-coated organic photoactive modules may be used to generate electricity on a large scale for grid power supply. In another example, spin-coated organic photoactive modules may be used to generate electricity on a small scale for home/office use. Alternatively, spin-coated organic photoactive modules may be used to generate electricity for stand-alone electrical devices, such as automobiles and spacecraft.
In the description herein for the embodiments of the present invention, numerous specific details are provided, such as examples of components and/or methods, to provide a thorough understanding of the embodiments of the present invention. One skilled in the relevant art will recognize, however, that an embodiment of the present invention can be practiced without one or more of the specific details, or with other apparatus, systems, assemblies, methods.

components, materials, parts, and/or the like. In other instances, well-known structures, materials, or operations are not specifically shown or described in detail to avoid obscuring aspects of the embodiments of the present invention.
Reference throughout this specification to "one embodiment", "an embodiment", or "a specific embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of an embodiment of the present invention and not necessarily in all embodiments. Thus, respective appearances of the phrases "in one embodiment", "in an embodiment", or "in a specific embodiment" in various places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, or characteristics of any specific embodiment of the present invention may be combined in any suitable manner with one or more other embodiments. It is to be understood that other variations and modifications of the embodiments of the present invention described and illustrated herein are possible in light of the teachings herein and are to be considered as part of the spirit and scope of the present invention.
It will also be appreciated that one or more of the elements depicted in the drawings/figures can also be implemented in a more separated or integrated manner, or even removed or rendered as inoperable in certain cases, as is useful in accordance with a particular application.
As used in the description herein and throughout the claims that follow, "a", "an", and "the" includes plural references unless the context clearly dictates othenA/ise. Also, as used in the description herein and throughout the claims that follow, the meaning of "in" includes "in" and "on" unless the context clearly dictates otherwise.

The foregoing description of illustrated embodiments of the present invention, including what is described in the Abstract, is not intended to be exhaustive or to limit the present invention to the precise forms disclosed herein. While specific embodiments of, and examples for, the present invention are described herein for illustrative purposes only, various equivalent modifications are possible within the spirit and scope of the present invention, as those skilled in the relevant art will recognize and appreciate. As indicated, these modifications may be made to the present invention in light of the foregoing description of illustrated embodiments of the present invention and are to be included within the spirit and scope of the present invention.
Thus, while the present invention has been described herein with reference to particular embodiments thereof, a latitude of modification, various changes and substitutions are intended in the foregoing disclosures, and it will be appreciated that in some instances some features of the embodiments of the present invention will be employed without a corresponding use of other features without departing from the scope and spirit of the present invention as set forth. Therefore, many modifications may be made to adapt a particular situation or material to the essential scope and spirit of the present invention. It is intended that the present invention not be limited to the particular terms used in following claims and/or to the particular embodiment disclosed as the best mode contemplated for carrying out this present invention, but that the present invention will include any and all embodiments and equivalents falling within the scope of the appended claims.

CLAIMS
WHAT IS CLAIMED IS:
1. A spin-coated organic photoactive module having improved packaging
efficiency, the spin-coated organic photoactive module comprising:
a panel for providing support; and
a plurality of spin-coated organic photoactive cells arranged over the panel,
the plurality of spin-coated organic photoactive cells being connected
electrically in a predefined manner, wherein each spin-coated organic
photoactive cell of the plurality of spin-coated organic photoactive cells
comprises:
a substrate having a symmetrical polygonal shape, the symmetrical
polygonal shape having more than four sides, the symmetrical polygonal
shape enabling improved packaging efficiency of the plurality of spin-coated
organic photoactive cells in the spin-coated organic photoactive module;
a first electrode formed over the substrate;
a spin-coated hole-transport layer formed over the first electrode;
a spin-coated photoactive layer fomied over the spin-coated hole-transport
layer; and
a second electrode formed over the spin-coated photoactive layer; wherein
the symmetrical polygonal shape of the substrate enables optimal formation
of the spin-coated hole-transport layer and the spin-coated photoactive layer.
2. The spin-coated organic photoactive module of claim 1, wherein the
symmetrical polygonal shape is a hexagonal shape, the hexagonal shape
enabling optimal usage of one or more materials used in the formation of the
spin-coated hole-transport layer and the spin-coated photoactive layer, and
optimal usage of the area of the substrate.
3. The spin-coated organic photoactive module of claim 1, wherein the
symmetrical polygonal shape is a circular shape, the circular shape enabling
optimal usage of one or more materials used in the formation of the spin-

coated hole-transport layer and the spin-coated photoactive layer, and optimal usage of the area of the substrate.
4. The spin-coated organic photoactive module of claim 1, wherein the first electrode is formed in a first region beyond a first radius from a centre of the substrate, and the spin-coated hole-transport layer, the spjn-coated photoactive layer and the second electrode are formed In a second region beyond a second radius from the centre of the substrate.
5. The spin-coated organic photoactive module of claim 4, wherein the first radius is smaller than the second radius, and a portion of the first electrode, between the first radius and the second radius, is not covered with the spin-coated hole-transport layer, the spin-coated photoactive layer and the second electrode.

6. The spin-coated organic photoactive module of claim 5, wherein the portion of the first electrode is used to draw at least one electrical connector.
7. A method of manufacturing a spin-coated organic photoactive module, the method comprising:
manufacturing a plurality of spin-coated organic photoactive cells, wherein manufacturing each spin-coated organic photoactive cell of the plurality of spin-coated organic photoactive cells comprises:
obtaining a substrate having a symmetrical polygonal shape, the symmetrical polygonal shape having more than four sides; forming a first electrode over the substrate;
forming a spin-coated hole-transport layer over the first electrode, by spin-coating a hole-transport material over the first electrode; forming a spin-coated photoactive layer over the spin-coated hole-transport layer, by spin-coating a photoactive material over the spin-coated hole-transport layer; and
forming a second electrode over the spin-coated photoactive layer; wherein the symmetrical polygonal shape of the substrate enables optimal formation of the spin-coated hole-transport layer and the spin-coated photoactive layer;

arranging the plurality of spin-coated organic photoactive cells over a panel, wherein the symmetrical polygonal shape of the substrate enables improved packaging efficiency of the plurality of spin-coated organic photoactive cells in the spin-coated organic photoactive module; and
connecting the plurality of spin-coated organic photoactive cells electrically in a predefined manner.
8. The method of claim 7, wherein the symmetrical polygonal shape is a
hexagonal shape, the hexagonal shape enabling optimal usage of the hole-
transport material and the photoactive material, and optimal usage of the area
of the substrate.
9. The method of claim 7, wherein the symmetrical polygonal shape is a circular
shape, the circular shape enabling optimal usage of the hole-transport
material and the photoactive material, and optimal usage of the area of the
substrate.
10. A spin-coated organic photoactive module substantially as herein above
described in the specification with reference to the accompanying drawings.