JP2016167511A - Solar battery module and manufacturing method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar battery module having a high photoelectric conversion efficiency.SOLUTION: A solar battery module includes a plurality of cells which are provided on a substrate and connected in series. Each cell includes a first electrode provided on the substrate, an organic photoelectric conversion film provided on the upper surface and side surface of the first electrode, and a second electrode provided on an upper surface of the organic photoelectric conversion film. In the cells at the second and subsequent stages, the respective side surfaces of the first electrode, the organic photoelectric conversion film and the second electrode at the side surface of the just preceding stage are located to be nearer to the preceding-stage cell side than the side surface of the second electrode of the preceding-stage cell at the opposite side to the preceding-stage cell.SELECTED DRAWING: Figure 2

Description

  Embodiments described herein relate generally to a solar cell module.

  As an organic photoelectric conversion element, for example, an organic thin film solar cell is known. An organic thin film solar cell is a solar cell using an organic thin film semiconductor in which a conductive polymer, fullerene and the like are combined. Organic thin-film solar cells can be produced by a simple method of applying or printing a photoelectric conversion film compared to solar cells based on inorganic materials such as silicon, CIGS (Copper Indium Gallium DiSelenide), and CdTe, which can reduce costs. there is a possibility. On the other hand, the conversion efficiency of the organic thin film solar cell has a problem that it is lower than that of a conventional inorganic solar cell.

  On the other hand, the efficiency of organic thin-film solar cells has improved dramatically in recent years, and the efficiency increased from 2% to 3% around 1995 to 11% in 2014.

One method for improving the photoelectric conversion efficiency of the organic thin film solar cell module is to increase the aperture ratio of the module. The aperture ratio is
Opening ratio = power generation area / (power generation area + non-power generation area)
In order to increase the aperture ratio, it is necessary to reduce the non-power generation area and increase the power generation area. The portion of the non-power generation area corresponds to the portion of the back electrode between the cells. However, it is difficult to reduce the non-power generation area to about 1 mm or less because of the strength limitation of the back electrode deposition mask. Therefore, to increase the aperture ratio, it is important to increase the power generation area, that is, to increase the cell width.

  Moreover, the density of short circuit current is also increasing with the increase in photoelectric conversion efficiency. When the density of the short circuit current increases, the resistance loss of the charge flowing through the transparent electrode of the cell cannot be ignored. In order to avoid this problem, the cell width should be reduced. However, reducing the cell width corresponds to reducing the power generation area, and as a result, the aperture ratio decreases.

JP 2012-28466 A JP 2004-303463 A

  This embodiment provides a solar cell module with high photoelectric conversion efficiency.

  The solar cell module of this embodiment includes a plurality of cells provided on a substrate and connected in series, and each cell is provided on a first electrode provided on the substrate and on an upper surface and a side surface of the first electrode. An organic photoelectric conversion film provided; and a second electrode provided on an upper surface of the organic photoelectric conversion film; and in the second and subsequent cells, the first electrode, the organic photoelectric conversion film, and the The side surface of the second electrode on the front cell side is located on the front cell side of the second electrode of the front cell on the side opposite to the front cell.

Sectional drawing which shows the example of the solar cell module explaining progress to embodiment. Sectional drawing which shows the solar cell module by 1st Embodiment. Sectional drawing which shows the structure of an organic photoelectric conversion film. 4A to 4F are cross-sectional views illustrating the manufacturing process of the solar cell module according to the first embodiment. 5A to 5D are cross-sectional views showing the manufacturing process of the solar cell module of the second embodiment. Sectional drawing which shows the solar cell module by 3rd Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  Before describing the embodiment, the background to the present invention will be described.

  The solar cell module has a plurality of cells connected in series, and the cells are provided on a transparent substrate, a transparent first electrode provided on the transparent substrate, and the first electrode. And an organic photoelectric conversion film and a second electrode (back electrode) provided on the organic photoelectric conversion film.

An example of a solar cell module having such a configuration is shown in FIG. The solar cell module 100 of this example has a plurality of cells 1 ₁ , 1 ₂ connected in series, and each cell 1 _i (i = 1, 2) is a transparent first provided on a transparent substrate 10. One electrode 12, an organic photoelectric conversion film 14 provided on the first electrode 12, and a second electrode 16 provided on the organic photoelectric conversion film 14 are provided. In each battery cell, the organic photoelectric conversion film 14 covers a part of the upper surface and the side surface of the first electrode 12. The second electrode 16 covers a part of the upper surface and the side surface of the organic photoelectric conversion film 14 and is connected to the side surface and a part of the upper surface of the first electrode 12 of the battery cell in the next stage.

In this solar cell module 100 of the first example, the power generation area of the cell 1 _1, from the end portion of the second electrode 16 to the edge of the cell 1 ₂ of the first electrode 12 located on the upper surface of the organic photoelectric conversion film of a region, the non-power generation region of the battery cells 1 _1, to the end portion located on the upper surface of the organic photoelectric conversion film 14 of the second electrode 16 of the cell 1 ₂ from the end of the cell 1 ₂ of the first electrode 12 It becomes the area of. The width of the power generation region of each cell 1 _i (i = 1, 2) is 12 mm, and the width of the non-power generation region of the cell 1 _i is 1 mm. At this time, the aperture ratio of each cell 1 _i (i = 1, 2) is 12 mm / (12 mm + 1 mm) = 92%. In order to increase the aperture ratio, it is necessary to reduce the area of the non-power generation region and increase the area of the power generation region. The area portion of the non-power generation region corresponds to the second electrode portion between the cells.

  When the size of the solar cell module is increased, the rigidity of the area portion of the non-power generation region in the second electrode vapor deposition mask is reduced, so that it is difficult to accurately position the area portion of the non-power generation region.

  Therefore, the width of the area portion of the non-power generation region of the second electrode deposition mask is limited to about 1 mm. Therefore, to increase the aperture ratio, it is important to increase the area of the power generation region, that is, increase the cell width.

  In addition, the short-circuit current density increases as the photoelectric conversion efficiency increases. When the short-circuit current density increases, the resistance loss of charges flowing through the transparent electrode (first electrode) of the cell cannot be ignored. In order to avoid this problem, it is necessary to reduce the width of the power generation region of the cell.

  However, reducing the width of the power generation region of the cell corresponds to reducing the area of the power generation region, and as a result, the aperture ratio decreases. For example, in the example shown in FIG. 1, when the width of the power generation region is reduced from 12 mm to 6 mm, the aperture ratio is reduced to 6 mm / (6 mm + 1 mm) = 86%.

  Therefore, the present inventors have developed a high aperture even if the width of the power generation region of each cell is reduced in order to suppress a decrease in photoelectric conversion efficiency due to an increase in the series resistance component of the transparent electrode due to an increase in the short-circuit current density. A solar cell module with high photoelectric conversion efficiency was invented because the rate was obtained. This solar cell module will be described below as an embodiment.

(First embodiment)
The solar cell module according to the first embodiment is shown in FIG. The solar cell module 100 of this embodiment has a plurality of cells 1 ₁ , 1 ₂ , 1 ₃ connected in series, and each cell 1 _i (i = 1, 2, 3) is on a transparent substrate 10. A transparent first electrode 12 provided on the first electrode 12, an organic photoelectric conversion film 14 provided on the first electrode 12, and a second electrode 16 provided on the organic photoelectric conversion film 14. The organic photoelectric conversion film 14, as shown in FIG. 3, the first carrier transporting layer 14 _1, a photoelectric conversion layer 14 ₂ is a laminated film and the second carrier transporting layer 14 ₃ are laminated in this order. The first carrier transporting layer 14 ₁ when the hole transport layer, a second carrier transporting layer 14 ₃ is an electron-transporting layer. The first carrier transporting layer 14 ₁ is used in an electron transporting layer, the second carrier transporting layer 14 ₃ is a hole transport layer. The photoelectric conversion layer has a bulk heterojunction structure in which an organic P-type semiconductor and an organic N-type semiconductor are mixed. In this specification, the term “transparent” means that the light transmittance is 60% or more, and the term “translucent” means that the light transmittance is 30% or more and less than 60%. means.

In each cell, the organic photoelectric conversion film 14 covers a part of the upper surface and the side surface of the first electrode 12. The second electrode 16 covers a part of the upper surface and the side surface of the organic photoelectric conversion film 14. Each cell ₁ i stage after the cell ₁ of the _first stage (i = 2,3), a part and the side of the upper surface of the second electrode 16 first electrode 12 of the cell _{1 i-1} of the preceding stage And covering. That is, each cell after the second stage is provided so as to partially overlap with the cell at the previous stage. In the first embodiment, in the cell ₁ i of the second and subsequent stages (i = 2,3), the first electrode 12, an organic photoelectric conversion film 14, and the second electrode 16, stage before the cell _{1 i -1} side end face, that is, the left end face in the drawing, is located on the front cell 1 _i-1 side with respect to the right end face (side surface) of the second electrode 16 of the front cell 1 _i-1 . . The light received by the solar cell module 100 is incident on the substrate 10 from the side opposite to the side where each cell is provided.

In this solar cell module 100 of the first embodiment, the power generation area of the cell 1 ₁ of the first stage is a region from the end face of the left side of the second electrode 16 to the right end face of the organic photoelectric conversion film 14. In each cell 1 _i (i = 2, 3) after the second stage, the power generation region is located on the right side of the organic photoelectric conversion film 14 from the right side surface of the second electrode 16 of the preceding cell 1 _i-1 . This is the area up to the side. The non-power generation region in the adjacent cell is a region corresponding to the thickness of the second electrode 16. When the first electrode 12, the organic photoelectric conversion film 14, and the second electrode 16 of each cell are formed by a meniscus coating method, each thickness can be formed with an accuracy of 0.1 mm. That is, since the thickness of the second electrode 16 can be 0.1 mm, the non-power generation region has a width of 0.1 mm. As in the case shown in FIG. 1, when the power generation region is 12 mm, the aperture ratio in the solar cell module of the first embodiment is 12 / (12 + 0.1) = 99.2%.

  As described above, according to the present embodiment, the width of the non-power generation region can be narrowed compared to the case shown in FIG. Can be obtained. That is, a solar cell module with high photoelectric conversion efficiency can be obtained.

(Production method)
Next, the manufacturing method of the solar cell module of 1st Embodiment is demonstrated with reference to FIG. 4A thru | or FIG. 4F. 4A to 4F are top views showing a method for manufacturing a solar cell module.

First, a first electrode 12 of the cell _{1 1} of the first stage is formed by a coating method on a transparent substrate 10 (FIG. 4A). Cell 1 ₁ of the organic photoelectric conversion film 14 of the first stage so as to cover a portion of the upper surface of the first electrode 12 is formed by a coating method (FIG. 4B). The second electrode 16 of the cell 1 ₁ of the first stage so as to cover a portion of the upper surface of the organic photoelectric conversion film 14 formed by a coating method (FIG. 4C). Subsequently, as shown in FIG. 4D, so as to cover a portion of the upper surface of the second electrode 16 of the cell 1 ₁ of the first stage, the first electrode 12 of the cell 1 of the _second stage is formed by a coating method . Cell 1 _second organic photoelectric conversion layer 14 of the second stage so as to cover a portion of the upper surface of the first electrode 12 is formed by a coating method (Fig. 4E). The second electrode 16 of the cell 1 ₂ of the second stage so as to cover a portion of the upper surface of the organic photoelectric conversion film 14 formed by a coating method (Fig. 4F). Hereinafter, the solar cell module of 1st Embodiment provided with the several cell connected in series is completed by repeating the process mentioned above. In the above manufacturing method, the organic photoelectric conversion film 14 covers the side surface of the first electrode 12 of the same cell, and the second electrode 16 is formed to cover the side surface of the organic photoelectric conversion film of the same cell.

(Second Embodiment)
Next, the solar cell module according to the second embodiment will be described with reference to FIGS. 5A to 5D. 5A to 5D are process cross-sectional views illustrating the method for manufacturing the solar cell module according to the second embodiment.

First, as shown in FIG. 5A, on a transparent substrate 10, a plurality of cells ₁ 1, _{1 2} of the basic structure (solar cell _element) to form a 2 1, _{2 2.} Each basic structure 2 _i (i = 1, 2) includes a transparent first electrode 12 formed on the substrate 10, an organic photoelectric conversion film 14 covering a part of the upper surface of the first electrode 12, and this photoelectric structure. And a second electrode 16 covering a part of the upper surface of the conversion film 14. These basic structures 2 ₁ and 2 ₂ are formed on the substrate 10 separately from each other. Further, in each basic structure 2 _i (i = 1, 2), the second electrode 16 is formed such that the right end face thereof coincides with the right end face of the organic photoelectric conversion film 16. In each basic structure 2 _i (i = 1, 2), the first electrode 12, the organic photoelectric conversion film 14, and the second electrode 16 are each formed using a coating method.

Subsequently, as shown in FIG. 5B, using the same material as the first electrode 12, the left side of the first electrode 12 of the base structure 2 ₂ covers the part of the upper surface of the second electrode 16 of the base structure 2 ₁ to connect to the side surface, to form a first first electrode 12 of the cell 1 _1. Thus, the basic structure _{2 1} a basic structure ₂ of the _second cell _{1 2} of the first cell _{1 1} are connected in series.

Thereafter, as shown in FIG. 5C, using the same material as the organic photoelectric conversion film 14, the basic structure 2 the basic structure covering the part of the area in the _second upper surface of the first electrode 12 2 ₂ organic photoelectric conversion film 14 to connect the to the left side surface of, forming an organic photoelectric conversion film 14 of the cell 1 _2.

Subsequently, as shown in FIG. 5D, by using the same material as the second electrode 16, the basic structure covers a partial area of the upper surface of the second cell 1 ₂ of the basic structure 2 ₂ of the organic photoelectric conversion film 14 2 so as to be connected to the left side of ₂ of the second electrode 16, to form the second second electrode 16 of the cell 1 _2.

  In the solar cell module manufactured in this way, as shown in FIG. 5D, there is no non-power generation region between adjacent cells. For this reason, the aperture ratio is 100%.

In the second embodiment, as in the first embodiment, the first electrode 12, the organic photoelectric conversion film 14, and the second electrode 16 in the cells 1 _i (i = 2) after the second stage. The end surface on the cell 1 _i-1 side in the preceding stage, that is, the end surface on the left side in the drawing, is the cell 1 _i-1 in the previous stage with respect to the right end surface (side surface) of the second electrode 16 of the cell 1 _{i-1 in the} previous stage. Located on the side. The light received by the solar cell module 100 is incident on the substrate 10 from the side opposite to the side where each cell is provided.

  As described above, according to the present embodiment, it is possible to eliminate a non-power generation region between adjacent cells, so that an aperture ratio of 100% can be obtained even if the width of the power generation region is reduced. That is, a solar cell module with high photoelectric conversion efficiency can be obtained.

(Third embodiment)
FIG. 6 shows a cross section of the solar cell module according to the third embodiment. The solar cell module 100 of the third embodiment has cells 1 ₁ , 1 ₂ , and 1 ₃ connected in series. Each cell 1 _i (i = 1, 2, 3) includes a first stacked structure 4a provided on the substrate 10, and a second stacked structure 4b covering a partial region of the upper surface of the first stacked structure 4a. It is equipped with.

  The first laminated structure 4a includes a transparent first electrode 12 provided on the substrate 10, an organic photoelectric conversion film 14a covering a partial region and side surface of the upper surface of the first electrode 12, and the organic photoelectric conversion film. A transparent or translucent first intermediate electrode 15a covering a partial region and side surface of the upper surface of 14a.

  The second stacked structure 4b includes a transparent or translucent second intermediate electrode 15b that covers a partial region and side surface of the upper surface of the first intermediate electrode 15a, and a partial region and side surface of the upper surface of the second intermediate electrode 15b. The organic photoelectric conversion film 14b that covers the upper surface of the organic photoelectric conversion film 14b, and a second electrode 16 that covers a partial region and side surface of the upper surface of the organic photoelectric conversion film 14b. The organic photoelectric conversion films 14a and 14b have the same configuration as the organic photoelectric conversion film 14 shown in FIG. 2, that is, if one has a normal structure, the other also has a normal structure, and one has an inverse structure. If there is, the other will also have an inverse structure.

In each cell 1 _i (i = 2, 3) in the second and subsequent stages, the first electrode 12 having the first stacked structure is connected to the second intermediate electrode 15b having the second stacked structure in the preceding cell 1 _i-1 . The organic photoelectric conversion film 14a having the first stacked structure is connected to the organic photoelectric conversion film 14b having the second stacked structure in the cell 1 _i-1 in the previous stage, and the intermediate electrode 15a having the first stacked structure is connected to the cell 1 in the previous stage. It is connected to the second electrode 16 of the second laminated structure in _i-1 .

The solar cell module 100 of 3rd Embodiment is manufactured using the manufacturing method similar to the manufacturing method demonstrated in 1st Embodiment, for example. For example, the manufacturing method of the solar cell module 100 of the third embodiment is performed as follows. Using the coating method described in the first embodiment, to form the first electrode 12, an organic photoelectric conversion film 14a and the first intermediate electrode 15a, the first laminated structure 4a in the cell 1 ₁ of the first stage, then, The second intermediate electrode 15b of the second stacked structure 4b is formed.

Next, in each cell 1 _i (i = 2, 3) after the second stage, the second intermediate electrode 15b of the cell 1 _i-1 in the previous stage is formed, and then connected to the second intermediate electrode 15b. The first electrode 12 of the cell 1 _i is formed. If the second intermediate electrode 15 b is the same material as the first electrode 12, it may be formed simultaneously with the first electrode 12. Thereafter, the organic photoelectric conversion film 14a of the first stacked structure 4a of the cell 1 _i (i = 2, 3) is formed together with the organic photoelectric conversion film 14b of the second stacked structure 4b of the preceding cell 1 _i-1 . Subsequently, the second electrode 16 of the second stacked structure 4b of the cell 1 _i-1 in the previous stage is formed. Subsequently, the intermediate electrode 15a of the first stacked structure 4a of the cell 1 _i (i = 2, 3) is formed so as to be connected to the second electrode 16 of the second stacked structure 4b of the preceding stage cell, and then The second intermediate electrode 15b of the second stacked structure 4b is formed. Hereinafter, the above-described steps are repeated.

In the solar cell module 100 of the third embodiment configured as described above, as shown in FIG. 6, there is no non-power generation region between adjacent cells 1 _i , 1 _{i + 1} (i = 1, 2). Therefore, the aperture ratio becomes 100%.

  Therefore, similarly to the second embodiment, the third embodiment can eliminate a non-power generation region between adjacent cells, and can obtain an aperture ratio of 100% even if the width of the power generation region is reduced. it can. That is, a solar cell module with high photoelectric conversion efficiency can be obtained.

  In addition, each cell has first and second laminated structures laminated so as to partially overlap, and the first and second intermediate electrodes are transparent or translucent. Therefore, in the first and second embodiments, the light absorbed by the second electrode can be transmitted through the first and second intermediate electrodes and used for photoelectric conversion in the organic photoelectric conversion film. As compared with the first and second embodiments, the photoelectric conversion efficiency can be further increased.

  Next, each element which comprises the solar cell module of the said 1st thru | or 3rd embodiment is demonstrated in detail.

(substrate)
The substrate 10 is for supporting other members. The substrate 10 is preferably transparent and capable of forming electrodes, and is not significantly altered by heat or an organic solvent. Examples of the material of the substrate 10 include inorganic materials such as alkali-free glass and quartz glass, polyethylene, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide, polyamide, polyamideimide, liquid crystal polymer, cycloolefin polymer, and the like. Examples include plastics and polymer films.

  Since the substrate 10 is on the light incident side, a transparent or translucent material is used. The thickness of the substrate 10 is not particularly limited as long as it has sufficient strength and flexibility to support other components.

  Further, for example, by providing an antireflection film having a moth-eye structure on the light incident surface of the substrate 10, it is possible to efficiently capture light and improve the energy conversion efficiency of the cell. The moth-eye structure has a structure having a regular protrusion arrangement of about 100 nm on the surface, and the refractive index in the thickness direction is continuously changed by this protrusion structure. For this reason, by providing an antireflection film, the surface where the refractive index changes discontinuously is eliminated, light reflection is reduced, and the photoelectric conversion efficiency of the cell is improved.

(First electrode 12)
The first electrode 12 is not particularly limited as long as it can be formed by a coating method and has light transparency and conductivity (transparent electrode).

  As a material of the transparent first electrode 12, an organic conductive polymer, polyethylenedioxythiophene-polystyrenesulfonic acid (hereinafter also referred to as PEDOT: PSS (poly (3,4-ethylenedioxythiopherene): polystyrene acid))), Polyaniline and its derivatives, polythiophene and its derivatives, etc. may be used.

  Examples of the material of the transparent first electrode 12 include a conductive metal oxide film and a semitransparent metal thin film. Specifically, indium oxide, zinc oxide, tin oxide, and their composites such as ITO (Indium Tin Oxide), fluorine-doped tin oxide (FTO), or indium, zinc, and oxide A tin oxide film or the like produced using conductive glass made of or the like is used. In particular, ITO or FTO is preferable. Moreover, you may use metals, such as gold | metal | money, platinum, silver, copper.

  The film thickness of the electrode 12 is preferably 30 nm to 300 nm, for example, when PEDOT: PSS is used. If it is thinner than 30 nm, the conductivity is lowered, the resistance is increased, and the photoelectric conversion efficiency is lowered. If it is thicker than 300 nm, the light absorption of PEDOT: PSS is great, and the photocurrent is reduced.

  Furthermore, the sheet resistance of the first electrode 12 is preferably as low as possible, and is preferably 10Ω / □ or less. The first electrode 12 may be a single layer or may be a laminate of layers made of materials having different work functions.

(First carrier transporting layer 14 ₁ and the second carrier transporting layer ₁₄ 3)
The first carrier transporting layer 14 ₁ and the second carrier transporting layer 14 ₂ shown in FIG. 3, one the other in the hole transporting layer functions as an electron transporting layer.

  In the case of a forward structure type organic thin film solar cell, the first carrier transport layer functions as a hole transport layer, and the second carrier transport layer functions as an electron transport layer. On the other hand, in the case of a reverse structure type organic thin film solar cell, the first carrier transport layer functions as an electron transport layer, and the second carrier transport layer functions as a hole transport layer.

  The hole transport layer has a function of blocking electrons and efficiently transporting only holes, and a function of preventing the disappearance of excitons generated at the interface between the photoelectric conversion layer and the hole transport layer. Similarly, the electron transport layer has a function of blocking holes and efficiently transporting only electrons, and a function of preventing the disappearance of excitons generated at the interface between the photoelectric conversion layer and the electron transport layer.

  Examples of the material containing the organic substances of the hole transport layer and the electron transport layer include amorphous titanium oxide obtained by hydrolyzing titanium alkoxide by PEDOT-PSS or a sol-gel method. Examples of inorganic substances include lithium fluoride, metallic calcium, zinc oxide, molybdenum oxide, and vanadium oxide.

(Photoelectric conversion layer 14 ₂ )
The photoelectric conversion layer 14 ₂ shown in FIG. 3 is arranged on a first carrier transporting layer 14 _1. The photoelectric conversion layer 14 ₂ is a photoelectric conversion layer of the heterojunction to the bulk. The bulk heterojunction photoelectric conversion layer is characterized in that a P-type semiconductor and an N-type semiconductor are mixed in the photoelectric conversion layer to form a micro layer separation structure. In the bulk heterojunction type, a mixed P-type semiconductor and N-type semiconductor form a PN junction having a nano-order size in the photoelectric conversion layer, and a current is obtained by utilizing photocharge separation generated at the junction surface.

  The P-type semiconductor is made of a material having an electron donating property. On the other hand, the N-type semiconductor is made of a material having an electron accepting property. In each embodiment, at least one of the P-type semiconductor and the N-type semiconductor may be an organic semiconductor.

  Examples of P-type organic semiconductors include polythiophene and derivatives thereof, polypyrrole and derivatives thereof, pyrazoline derivatives, arylamine derivatives, stilbene derivatives, triphenyldiamine derivatives, oligothiophene and derivatives thereof, polyvinylcarbazole and derivatives thereof, polysilane and derivatives thereof. Polysiloxane derivatives having aromatic amines in the side chain or main chain, polyaniline and derivatives thereof, phthalocyanine derivatives, porphyrins and derivatives thereof, polyphenylene vinylene and derivatives thereof, polythienylene vinylene and derivatives thereof, and the like can be used, These may be used in combination. These copolymers may be used, and examples thereof include a thiophene-fluorene copolymer, a phenylene ethynylene-phenylene vinylene copolymer, and the like.

  A preferred P-type organic semiconductor is polythiophene, which is a conductive polymer having π conjugation, and derivatives thereof. Polythiophene and its derivatives can ensure excellent stereoregularity and have relatively high solubility in a solvent. Polythiophene and derivatives thereof are not particularly limited as long as they are compounds having a thiophene skeleton. Specific examples of polythiophene and derivatives thereof include polyalkylthiophenes such as poly-3-methylthiophene, poly-3-butylthiophene, poly-3-hexylthiophene, poly-3-octylthiophene, poly-3-decylthiophene, poly-3-dodecylthiophene, etc. Polyarylthiophene such as poly-3-phenylthiophene and poly-3- (p-alkylphenylthiophene); poly-3-butylisothionaphthene, poly-3-hexylisothionaphthene, poly-3-octylisothionaphthene, poly-3- And polyalkylisothionaphthene such as decylisothionaphthene; polyethylenedioxythiophene and the like.

  In recent years, PCDTBT (poly [N-9 "-hepta-decanyl-2,7-carbazole-alt-5,5- (4 ', 7'-di ()), which is a copolymer of carbazole, benzothiadiazole and thiophene. -2-thienyl-2 ′, 1 ′, 3′-benzothiadiazole)]) and the like, and PTB7 (poly [[4,8-bis [(2- Ethylhexyl) oxy] benzo [1,2-b: 4-5-b ′] dithiophene-2,6-diyl] [3-fluoro-2-[(2-ethylhexyl) carbonyl] thieno [3,4-4] Thiophenzyl]) and PTB7-Th (poly [[4,8-bis [5- (2-ethylhexyl) thiophen-2-yl] benzo [1,2-b: 4-5-b ′] dithio E emissions - co -3-fluoro-thieno [3,4-b] thiophene-2-carboxylate]) derivatives, such as are known as compounds obtained an excellent photoelectric conversion efficiency.

  These conductive polymers can be formed by applying a solution dissolved in a solvent. Therefore, there is an advantage that a large-area organic thin film solar cell can be manufactured at low cost with inexpensive equipment by a printing method or the like.

Fullerene and its derivatives are preferably used as the N-type organic semiconductor. The fullerene derivative used here is not particularly limited as long as it is a derivative having a fullerene skeleton. Specific examples include derivatives composed of C ₆₀ , C ₇₀ , C ₇₆ , C ₇₈ , C _{84 and the} like as a basic skeleton. In the fullerene derivative, carbon atoms in the fullerene skeleton may be modified with an arbitrary functional group, and these functional groups may be bonded to each other to form a ring. Fullerene derivatives also include fullerene bonded polymers. A fullerene derivative having a functional group with high affinity for the solvent and high solubility in the solvent is preferred.

Examples of the functional group in the fullerene derivative include hydrogen atom; hydroxyl group; halogen atom such as fluorine atom and chlorine atom; alkyl group such as methyl group and ethyl group; alkenyl group such as vinyl group; cyano group; methoxy group and ethoxy group. Alkoxy groups such as phenyl groups, aromatic hydrocarbon groups such as naphthyl groups, and aromatic heterocyclic groups such as thienyl groups and pyridyl groups. Specific examples include hydrogenated fullerenes such as C ₆₀ H ₃₆ and C ₇₀ H ₃₆ , oxide fullerenes such as C ₆₀ and C ₇₀ , fullerene metal complexes, and the like.

Among the above, a fullerene derivative, 60PCBM ([6,6] - phenyl _{C 61} butyric acid methyl ester), or 70PCBM - it is particularly preferred to use ([6,6] phenyl _{C 71} butyric acid methyl ester).

When using the unmodified fullerene, it is preferred to use a C _70. Fullerene C ₇₀ is the generation efficiency of photocarriers high, are suitable for use in organic thin film solar cell.

  The mixing ratio of the N-type organic semiconductor and the P-type organic semiconductor in the photoelectric conversion layer is preferably about N: P = 1: 1 when the content of the N-type organic semiconductor is a P3AT system, and p When the type semiconductor is a PCDTBT system, it is preferable that N: P = 4: 1. When the p-type semiconductor is PTB7, it is preferable that N: P = 1: 1.5.

  In order to apply an organic semiconductor, it is necessary to dissolve in a solvent. Examples of the solvent used therefor include toluene, xylene, tetralin, decalin, mesitylene, n-butylbenzene, sec-butylbenzene, and tert-butylbenzene. Unsaturated hydrocarbon solvents such as, halogenated aromatic hydrocarbon solvents such as chlorobenzene, dichlorobenzene, and trichlorobenzene, carbon tetrachloride, chloroform, dichloromethane, dichloroethane, chlorobutane, bromobutane, chloropentane, chlorohexane, bromohexane, Halogenated saturated hydrocarbon solvents such as chlorocyclohexane and ethers such as tetrahydrofuran and tetrahydropyran. In particular, a halogen-based aromatic solvent is preferable. These solvents can be used alone or in combination.

  As a method of applying a solution to form a film, spin coating, dip coating, casting, bar coating, roll coating, wire bar coating, spraying, screen printing, gravure printing, flexographic printing, offset Examples thereof include a printing method, gravure / offset printing, dispenser coating, nozzle coating method, capillary coating method, and ink jet method, and these coating methods can be used alone or in combination.

(Second electrode)
The second electrode 16 is formed by depositing a conductive material by vacuum deposition, sputtering, ion plating, plating, coating, or the like. Examples of the electrode material include a metal paste, a metal nano ink, a conductive metal thin film, and a metal oxide film.

  The second electrode 16 may be a single layer or may be a laminate of layers made of materials having different work functions. Examples of the single layer include silver, aluminum, gold, and copper. Examples of the alloy include a lithium-aluminum alloy, a lithium-magnesium alloy, a lithium-indium alloy, a magnesium-silver alloy, a magnesium-indium alloy, a magnesium-aluminum alloy, an indium-silver alloy, and a calcium-aluminum alloy.

  The film thickness of the second electrode 16 is 1 nm to 500 nm, preferably 10 nm to 300 nm. When the film thickness is smaller than the above range, the resistance becomes too large and the generated charge cannot be sufficiently transmitted to the external circuit.

  Next, examples will be described.

Example 1
Example 1 is a solar cell module according to the second embodiment having a forward structure type organic photoelectric conversion film (FIGS. 5A to 5D). The solar cell module of Example 1 is formed as follows.

  First, PET is used as the substrate 10 and PEDOT: PSS is used as the first electrode. Here, the PEDOT: PSS layer functions as the positive electrode (first electrode in Example 1) and the hole transport layer (first carrier transport layer of the organic photoelectric conversion film) of the forward structure type organic photoelectric conversion film 14, respectively. First, PEDOT: PSS is coated on the substrate 10 in a strip shape with a width of 6 mm using a die coat coating apparatus, and dried at 150 ° C. Thereby, the first carrier transport layer of the first electrode 12 and the organic photoelectric conversion film 14 is formed.

  Thereafter, a solution in which PTB7-Th of P-type organic semiconductor material and 70PCBM of n-type organic semiconductor material are dissolved is applied using a die coater so as to overlap the area of all cells, and dried at 50 ° C. Thereby, the photoelectric conversion layer of the organic photoelectric conversion film 14 is formed.

  Next, as before, a titanium oxide layer as an electron transport layer of the organic photoelectric conversion film 14 is applied and dried so as to overlap the area of all cells.

  Ag is formed as the second electrode 16 by vapor deposition using a mask so as to overlap the area of all cells. Here, the produced solar cell elements (basic structure of the cell) have an opening of 6 mm and a non-opening of 1 mm.

Next, the solar cell element _{1 2} of the basic structure _{2 2} adjacent the part of the Ag electrode of the basic structure _{2 1} of the solar cell element _{1 1} PEDOT: the area between the up PSS, PEDOT: PSS coating method The film is formed. Subsequently, a solution of 70PCBM of PTB7-Th and n-type organic semiconductor material of P-type organic semiconductor material, the base structure _{2 1} of the solar cell element _{1 1} PEDOT: adjoining solar cell from a part of the PSS layer the area between the up photoelectric conversion layer of the basic structure 2 ₂ of element 1 ₂ is deposited by a coating method. Similarly, the area between the up titanium oxide layer of the solar cell element 1 ₂ of the basic structure 2 ₂ adjacent the portion of the photoelectric conversion layer of the basic structure 2 ₁ of the solar cell element 1 ₁ is an electron transport layer The titanium oxide layer is applied and dried so as to overlap the area of all cells.

Finally, between the Ag electrode of the basic structure 2 ₁ of the solar cell element 1 ₂ adjacent the part of the titanium oxide layer of the basic structure 2 ₁ of the solar cell element 1 _1, and drying the coated Ag paste solution.

  Thus, the solar cell element structure was also formed in the non-opening portion, so that the initial aperture ratio was 6 mm / (6 mm + 1 mm) = 85.7% and increased to 100%.

(Example 2)
Example 2 is a solar cell module according to the second embodiment having an inverted structure type organic photoelectric conversion film. The solar cell module of Example 2 is formed as follows.

  First, PET is used as the substrate 10 and PEDOT: PSS is used as the first electrode. As an electron transport layer, PEDOT: PSS is applied to the substrate 10 in a strip shape with a width of 6 mm using a die coat application device, and dried at 150 ° C. Thereby, the 1st electrode 12 and electron transport layer (1st carrier transport layer of the organic photoelectric converting film 14) which consist of PEDOT: PSS are formed.

  Thereafter, a solution in which PTB7-Th of P-type organic semiconductor material and 70PCBM of N-type organic semiconductor material are dissolved is applied using a die coater so as to overlap the area of all cells and dried at 50 ° C. Thereby, the photoelectric conversion layer of the organic photoelectric conversion film 14 is formed.

  Next, a PEDOT: PSS layer as a hole transport layer (second carrier transport layer of the organic photoelectric conversion film 14) is applied and dried so as to overlap the area of all cells.

  Ag paste is formed so as to overlap the area of all cells. Here, the produced solar cell elements have an opening of 6 mm and a non-opening of 1 mm.

Next, the solar cell element _{1 2} adjacent the part of the Ag electrode of the solar cell element _{1 1} PEDOT: between PSS, PEDOT: PSS and deposited by a coating method. Subsequently, the PTB7-Th of P-type organic semiconductor material, the solution obtained by dissolving 70PCBM of N-type organic semiconductor material, the solar cell device 1 PEDOT: photoelectric solar cell element _{1 2} adjacent the part of the PSS layer A film is formed in a region between the conversion layer by a coating method. Similarly, the solar cell element _{1 2} adjacent the portion of the photoelectric conversion layer of the solar cell element _{1 1} PEDOT: the area between the up PSS layer is PEDOT hole transport layer: PSS layer of all cells Apply and dry to overlap the area.

  Finally, an Ag paste solution is applied to a region between a part on the PEDOT: PSS layer of the solar cell element 1 and an Ag electrode of the adjacent solar cell element 2 and dried.

  Thus, the solar cell element structure was also formed in the non-opening portion, so that the initial aperture ratio was 6 mm / (6 mm + 1 mm) = 85.7% and increased to 100%.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the invention described in the claims and equivalents thereof as well as included in the scope and gist of the invention.

1 ₁ to 1 ₃ cell 2 _{1, 2 2} cell basic structure 10 substrate 12 first electrode 14 organic photoelectric conversion film 14a first organic photoelectric conversion layer 14b second organic photoelectric conversion layer 14 ₁ first carrier transporting layer 14 ₂ photoelectrically Conversion layer 14 ₃ Second carrier transport layer 15 a, 15 b Intermediate electrode 16 Second electrode 100 Solar cell module

Embodiments described herein relate generally to a solar cell module and a manufacturing method thereof .

The present embodiment provides a solar cell module with high photoelectric conversion efficiency and a method for manufacturing the same.

Claims (10)

A plurality of cells provided on a substrate and connected in series, each cell including a first electrode provided on the substrate, an organic photoelectric conversion film provided on an upper surface and a side surface of the first electrode, A second electrode provided on the upper surface of the organic photoelectric conversion film,
In the second and subsequent cells, the side surfaces of the first electrode, the organic photoelectric conversion film, and the second electrode on the previous cell side are opposite to the previous cell of the second electrode of the previous cell. The solar cell module which is located in the cell side of the front | former stage rather than the side surface of a side.   The solar cell module according to claim 1, wherein in each cell, the second electrode is also provided on a side surface of the organic photoelectric conversion film.   2. The solar cell module according to claim 1, wherein, in each cell, the second electrode has a side surface on the opposite side to the preceding cell at the same position as a side surface on the opposite side to the preceding cell of the organic photoelectric conversion film.   The solar cell module according to claim 1, wherein the substrate and the first electrode are transparent.   The organic photoelectric conversion film includes a hole transport layer, an electron transport layer, and a photoelectric conversion layer provided between the hole transport layer and the electron transport layer. The solar cell module in any one.   In each cell, the organic photoelectric conversion film is provided in a part of the upper surface of the first electrode and the side surface, and the second electrode is provided in a part of the upper surface of the organic photoelectric conversion film. The solar cell module according to any one of claims 1 to 5. A plurality of cells provided on a substrate and connected in series, each cell having a first laminated structure provided on the substrate and a second laminated structure provided on an upper surface and a side surface of the first laminated structure And comprising
The first stacked structure includes a first electrode provided on the substrate, a first organic photoelectric conversion film provided on an upper surface and a side surface of the first electrode, and an upper surface and a side surface of the first organic photoelectric conversion film. A first intermediate electrode provided on
The second stacked structure includes a second intermediate electrode provided on the upper surface and the side surface of the first intermediate electrode, a second organic photoelectric conversion film provided on the upper surface and the side surface of the second intermediate electrode, and the second A second electrode provided on part of the upper surface and side surface of the organic photoelectric conversion film,
In each cell after the second stage, the first electrode is connected to the second intermediate electrode of the previous stage cell, the first organic photoelectric conversion film is connected to the second organic photoelectric conversion film of the previous stage cell, The solar cell module, wherein the first intermediate electrode is connected to a second electrode of a preceding cell.   The solar cell module according to claim 7, wherein the substrate and the first electrode are transparent.   The solar cell module according to claim 7 or 8, wherein the first and second intermediate electrodes are transparent or translucent.   Each of the first and second organic photoelectric conversion films includes a hole transport layer, an electron transport layer, and a photoelectric conversion layer provided between the hole transport layer and the electron transport layer. The solar cell module according to claim 7.

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