CN116014019A

CN116014019A - Thin film solar cell, preparation method thereof, photovoltaic module and power generation equipment

Info

Publication number: CN116014019A
Application number: CN202310034249.3A
Authority: CN
Inventors: 刘德涛; 王硕; 辛凯; 刘云峰
Original assignee: Huawei Digital Power Technologies Co Ltd
Current assignee: Huawei Digital Power Technologies Co Ltd
Priority date: 2023-01-10
Filing date: 2023-01-10
Publication date: 2023-04-25

Abstract

According to the thin film solar cell, the preparation method thereof, the photovoltaic module and the power generation equipment, the optical structure is arranged on the back surface of the thin film solar cell and comprises the alternately arranged light conversion layers and the distributed Bragg reflection layers, the light conversion layers can convert light which is not fully absorbed by the thin film solar cell and is out of the absorbable wave band into light which is in the absorbable wave band, the transmission direction of the light converted by the light conversion layers is adjusted through the distributed Bragg reflection layers, so that the thin film solar cell absorbs the incident light of the thin film solar cell, the optical utilization rate of the incident light of the thin film solar cell is improved, the utilization rate of the light out of the absorbable wave band of the thin film solar cell is improved, and the overall output power of the thin film solar cell is further improved.

Description

Thin film solar cell, preparation method thereof, photovoltaic module and power generation equipment

Technical Field

The application relates to the technical field of batteries, in particular to a thin film solar cell, a preparation method thereof, a photovoltaic module and power generation equipment.

Background

Solar energy is a renewable energy source, has the advantages of cleanness, safety, wide application and the like, and has important roles in long-term energy strategy. Photovoltaic power generation is a technology that uses the photovoltaic effect of semiconductor materials to convert light energy into electrical energy. The core unit of photovoltaic power generation is photovoltaic module, and common photovoltaic module includes single face battery module and two-sided battery module, and two-sided battery module and the difference in single face battery module lie in: the double-sided battery assembly is formed by packaging double-sided thin film solar cells, and the front and the back of each double-sided thin film solar cell can receive sunlight irradiation and generate electric energy, so that the power generation efficiency of the double-sided battery assembly is greatly improved relative to that of the single-sided battery assembly.

Generally, the structure of a bifacial thin film solar cell includes: a front transparent electrode, a back transparent electrode, and a light absorption conversion layer disposed between the front transparent electrode and the back transparent electrode. Since both the front and back surfaces in the double-sided thin film solar cell are transparent electrodes, when the thickness of the light absorption conversion layer is low, there is a case where light of a long wavelength band in the absorption band cannot be sufficiently absorbed, resulting in light waste. Further, the infrared light may not be fully utilized due to factors limited by the forbidden bandwidth of the light absorbing conversion layer material.

Disclosure of Invention

The embodiment of the application provides a thin film solar cell, a preparation method thereof, a photovoltaic module and power generation equipment, which are used for improving the light utilization rate.

In a first aspect, embodiments of the present application provide a thin film solar cell, including: the battery comprises a first transparent substrate, a battery structure positioned on the first transparent substrate, and an optical structure positioned on the battery structure. The battery structure is used for absorbing light in a first wavelength range, generating electron hole pairs through the absorbed light, forming photo-generated carriers and generating photo-generated current. That is, the light in the first wavelength range is light within the absorbable band of the cell structure.

Illustratively, the battery structure may include: the first conductive layer, the first charge transmission layer, the light absorption conversion layer, the second charge transmission layer and the second conductive layer are sequentially arranged on the first transparent substrate. Alternatively, the materials of the first conductive layer and the second conductive layer may be both transparent conductive materials, and then the thin film solar cell in the embodiment of the present application may include a double-sided thin film solar cell. Wherein L31 represents light within the first wavelength range in the front-side incident light, L32 represents light outside the first wavelength range in the front-side incident light, L31 and L32 are incident from one side of the first conductive layer, and the light absorption conversion layer generates electron hole pairs after absorbing L31 to form photogenerated carriers, thereby generating a photogenerated current. L41 represents light within the first wavelength range of the back-side incident light, L42 represents light outside the first wavelength range of the back-side incident light, L41 and L42 are incident from one side of the second conductive layer, and the light absorption conversion layer also generates electron hole pairs after absorbing L41, forming photogenerated carriers, and also generates photogenerated current.

And, the optical structure comprises: at least one light conversion layer and at least one distributed Bragg reflection layer alternately arranged; the film layer of the optical structure furthest from the cell structure is the distributed Bragg reflection layer. Wherein the light conversion layer is used for converting light incident on the battery structure after passing through the battery structure into light of a first wavelength range. The distributed Bragg reflection layer is used for reflecting light incident on the distributed Bragg reflection layer, so that the propagation direction of the reflected light is directed to the cell structure.

Based on this, due to the thickness of the light-absorbing conversion layer and the forbidden bandwidth of the material thereof, the light L31 may not be sufficiently absorbed by the light-absorbing conversion layer (e.g., the light of the first wavelength middle-long band may not be sufficiently absorbed by the light-absorbing conversion layer), and thus a portion of the light (e.g., the light of the first wavelength middle-long band) may be incident on the light-converting layer after passing through the cell structure. The light L32 is not directly absorbed by the light-absorbing conversion layer, and this light is also incident on the light-converting layer after passing through the cell structure. The light conversion layer converts the light incident thereon after passing through the cell structure into light in a first wavelength range. I.e. the light converted by the light-converting layer can be absorbed by the light-absorbing converting layer, the light-converting layer can convert light incident on the front side and not sufficiently absorbed by the thin-film solar cell and lying outside its absorbable band into light within its absorbable band. In addition, some of the light converted by the light conversion layer is directed to the cell structure in the propagation direction, and the light directed to the cell structure can be absorbed again by the light absorption conversion layer, so as to improve the output power of the thin film solar cell. However, some of the light converted by the light conversion layer also has a propagation direction deviating from the cell structure, and the light deviating from the cell structure may directly enter the distributed bragg reflection layer, and the propagation direction of the light is changed by the distributed bragg reflection layer, so that the propagation direction of the light is directed to the cell structure, and is absorbed again by the light absorption conversion layer, thereby further improving the output power of the thin film solar cell.

Therefore, in the thin film solar cell provided by the embodiment of the application, the optical structure is arranged on the back surface of the thin film solar cell, and the optical structure comprises the alternately arranged light conversion layers and the distributed Bragg reflection layers, the light conversion layers can convert the light which is not fully absorbed by the thin film solar cell and is out of the absorbable wave band into the light which is in the absorbable wave band, and the transmission direction of the light converted by the light conversion layers is adjusted through the distributed Bragg reflection layers, so that the thin film solar cell absorbs the light, the optical utilization rate of the incident light of the thin film solar cell is improved, the utilization rate of the light out of the absorbable wave band of the thin film solar cell is improved, and the total output power of the thin film solar cell is further improved.

In the embodiment of the application, the thin film solar cell may be: any one of a cadmium telluride cell, a copper indium gallium selenide cell, a perovskite cell or an organic solar cell is included as long as the cell includes a light absorption conversion layer, and the light absorption conversion layer absorbs light to generate electron hole pairs so as to generate current, which belongs to the protection scope of the present application.

Optionally, the wavelength range of the light converted by the light conversion layer is the second wavelength range. Illustratively, the wavelength range of the light converted by the light conversion layer may be the same as the first wavelength range, i.e. the second wavelength range corresponding to the light conversion layer is the same as the first wavelength range. Alternatively, the wavelength range of the light converted by the light conversion layer may be located within the first wavelength range, that is, the first wavelength range includes the second wavelength range corresponding to the light conversion layer. For example, the first wavelength range may be 400nm to 800nm, and the second wavelength range corresponding to the light conversion layer may be 500nm to 600nm, or the second wavelength range corresponding to the light conversion layer may be 480nm to 700nm. Of course, in practical applications, the first wavelength range and the second wavelength range may be determined according to requirements of practical applications, which is not limited in this application.

In some examples, the material of the light conversion layer may include an up-conversion material. Wherein the up-conversion material is for converting light of a wavelength greater than a maximum of the second wavelength range to light in the second wavelength range. The wavelength range of light that can be absorbed by the light conversion layer in this way can include light of a maximum wavelength that is greater than the second wavelength range, thereby converting light of a maximum wavelength that is greater than the second wavelength range into light in the second wavelength range. For example, the upconverting material is operable to convert light having a wavelength greater than 600nm to light in a second wavelength range, where the second wavelength range may be 500nm to 600 nm. Alternatively, the up-conversion material may convert light in the wavelength range of 600nm to 1100nm to light in the second wavelength range, while the second wavelength range may be 500nm to 600 nm.

Illustratively, the upconverting material includes, but is not limited to, an upconverting quantum dot material. Optionally, the upconverting quantum dot material includes, but is not limited to: naYF ₄ :Yb ³⁺ :Er ³⁺ A quantum dot material (for example, the average size thereof is 20 nm), etc., which may be a combination of a plurality of materials, and the material system is adjusted according to the wavelength conversion requirement, and the up-conversion material is not limited in this application.

Illustratively, the material of the light conversion layer may further include: dispersing agent for dispersing up-conversion quantum dot material, the dispersing agent including nanoparticles (for exampleFor example, siO ₂ ) And a solvent, and the ratio between the concentration of the up-conversion quantum dot material in the dispersant and the concentration of the nanoparticle in the dispersant ranges from 0.01 to 0.1. Optionally, the ratio between the concentration of the upconverting quantum dot material in the dispersant and the concentration of the nanoparticle in the dispersant ranges from 0.03 to 0.07. For example, the ratio between the concentration of the upconverting quantum dot material in the dispersant and the concentration of the nanoparticle in the dispersant is 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, etc., without limitation herein.

In other examples, the material of the light conversion layer may include a down conversion material. Wherein the down-conversion material is for converting light of a minimum wavelength less than the second wavelength range to light in the second wavelength range. The wavelength range of light that can be absorbed by the light conversion layer may include light of a minimum wavelength less than the second wavelength range, thereby converting light of a minimum wavelength less than the second wavelength range into light in the second wavelength range. For example, the down-conversion material is used to convert light having a wavelength less than 500nm into light in a second wavelength range, when the second wavelength range may be 500nm to 600 nm. Alternatively, the down-conversion material may convert light in the wavelength range of 200nm to 500nm to light in the second wavelength range, while the second wavelength range may be 500nm to 600 nm.

Illustratively, the down-conversion material includes, but is not limited to, a down-conversion quantum dot material. Optionally, the down-converting quantum dot material includes, but is not limited to: quantum dots containing rare earth ions (e.g., without limitation, sr ₂ SiO ₄ :Re ²⁺ ) Vanadate quantum dots, indium phosphide quantum dots, zinc sulfide quantum dots, and perovskite quantum dots (e.g., without limitation, csPbBr ₃ ) At least one of them. Of course, the material system may be adjusted according to the wavelength conversion requirement, and the present application is not limited to the down-conversion material.

Illustratively, the material of the light conversion layer may further include: a dispersant for dispersing a down-conversion quantum dot material, the dispersant comprising nanoparticles and a solvent, and a ratio between a concentration of the down-conversion quantum dot material in the dispersant and a concentration of the nanoparticles in the dispersant ranges from 0.01 to 0.1. Optionally, the ratio between the concentration of the down-converting quantum dot material in the dispersant and the concentration of the nanoparticle in the dispersant ranges from 0.03 to 0.07. For example, the ratio between the concentration of the down-converting quantum dot material in the dispersant and the concentration of the nanoparticle in the dispersant is 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, etc., without limitation herein.

In still other examples, the material of the light conversion layer may include both an up-conversion material and a down-conversion material. Thus, the wavelength range of the light which can be absorbed by the light conversion layer can comprise light with a minimum wavelength smaller than the second wavelength range and light with a maximum wavelength larger than the second wavelength range, so that the amount of the light in the converted second wavelength range is increased, the amount of the light incident into the light absorption conversion layer is further increased, the light loss is reduced, and the light utilization rate is improved.

Illustratively, the material of the light conversion layer may further include: a dispersant for dispersing a quantum dot material (the quantum dot material herein includes an up-conversion quantum dot material and a down-conversion quantum dot material), the dispersant including nanoparticles and a solvent, and a ratio between a concentration of the quantum dot material in the dispersant and a concentration of the nanoparticles in the dispersant ranges from 0.01 to 0.1. Alternatively, the ratio between the concentration of the quantum dot material in the dispersant and the concentration of the nanoparticle in the dispersant ranges from 0.03 to 0.07. For example, the ratio between the concentration of the quantum dot material in the dispersant and the concentration of the nanoparticle in the dispersant is 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, etc., without limitation.

In some possible embodiments, the adjacent distributed bragg reflection layer and the light conversion layer are used as a structural group, and the distributed bragg reflection layer in the same structural group is positioned on one side of the light conversion layer away from the cell structure; in the same structure group, the wavelength range of the light converted by the light conversion layer is within the wavelength range of the light reflected by the distributed Bragg reflection layer. This allows the propagation direction of the light converted by the light conversion layer to be changed by the distributed bragg reflection layer.

Illustratively, the wavelength range of the light reflected by the distributed Bragg reflection layer is a third wavelength range. Optionally, the third wavelength range is located within the first wavelength range.

In some possible implementations, the distributed bragg reflection layer includes a plurality of first refractive index layers and a plurality of second refractive index layers; the refractive index of the first refractive index layer is larger than that of the adjacent second refractive index layer; the plurality of first refractive index layers and the plurality of second refractive index layers are alternately arranged, and the distributed Bragg reflection layer is in contact with the light conversion layer through the first refractive index layers. Wherein the number of first refractive index layers is the same as the number of second refractive index layers. Thus, the distributed Bragg reflection layer can be formed by sequentially repeating the first refractive index layer and the second refractive index layer.

In some possible implementations, each of the plurality of first refractive index layers in the same distributed bragg reflection layer has the same refractive index. Thus, the design difficulty can be reduced, and the preparation difficulty can be reduced.

Alternatively, the thickness of each of the plurality of first refractive index layers may be made the same. The thickness of the thin film of the first refractive index layer is determined by both the center wavelength of the reflected light thereof (such as the center wavelength in the third wavelength range) and the refractive index thereof, for example, the relationship among the thickness h1 of the first refractive index layer, the refractive index n1, and the center wavelength λ0 is satisfied: h1×n1=λ0/4.

In some possible embodiments, the refractive index of the first refractive index layer of the plurality of first refractive index layers may also be sequentially increased in the same distributed bragg reflection layer in a direction pointing from the first transparent substrate to the cell structure. Alternatively, in the same distributed bragg reflection layer in the direction from the first transparent substrate toward the cell structure, the refractive index of the first refractive index layer among the plurality of first refractive index layers may be sequentially reduced. This allows the refractive indices of the different first refractive index layers to be adjustable.

In some possible embodiments, each of the plurality of second refractive index layers in the same distributed bragg reflection layer has the same refractive index. Thus, the design difficulty can be reduced, and the preparation difficulty can be reduced.

Alternatively, the thickness of each of the plurality of second refractive index layers may be made the same. The thickness of the thin film of the second refractive index layer is determined by both the center wavelength of the reflected light thereof (such as the center wavelength in the third wavelength range) and the refractive index thereof, for example, the relationship among the thickness h2, the refractive index n2, and the center wavelength λ0 of the second refractive index layer is satisfied: h2=n2=λ0/4.

In some possible embodiments, in a direction from the first transparent substrate toward the cell structure, the refractive index of the second refractive index layer of the plurality of second refractive index layers sequentially increases in the same distributed bragg reflection layer. Alternatively, in the same distributed bragg reflection layer in a direction from the first transparent substrate toward the cell structure, the refractive index of the second refractive index layer of the plurality of second refractive index layers sequentially decreases. This allows the refractive index of the different second refractive index layer to be adjustable.

In this embodiment, taking the case that the refractive index of each first refractive index layer is the same and the refractive index of each second refractive index layer is the same as an example, the distributed bragg reflection layer may be formed by using two films with different refractive indexes to periodically and alternately appear. And, the bandwidth (e.g., third wavelength range) of the reflected light reflected by the distributed bragg reflection layer may be determined by the refractive index difference of the materials of the first refractive index layer and the second refractive index layer. For example, the larger its refractive index difference, the larger the bandwidth of the reflected light.

In some possible embodiments, the optical structure comprises: one or more distributed Bragg reflection layers, and one or more light conversion layers. Wherein when the optical structure includes a plurality of distributed bragg reflection layers, the wavelength ranges of the reflected light (i.e., the third wavelength ranges) corresponding to different ones of the distributed bragg reflection layers may be made different.

Optionally, the plurality of distributed bragg reflection layers are defined as a 1 st distributed bragg reflection layer to a Q-th distributed bragg reflection layer in a direction from the first transparent substrate toward the cell structure, and a minimum value of a wavelength range of reflected light (i.e., the third wavelength range) corresponding to the Q-th distributed bragg reflection layer is not greater than a maximum value of a wavelength range of reflected light (i.e., the third wavelength range) corresponding to the q+1-th distributed bragg reflection layer. Wherein Q is an integer greater than 1, and Q is an integer greater than or equal to 1 and less than or equal to Q.

Illustratively, the minimum value of the third wavelength range corresponding to the q-th distributed bragg reflection layer is equal to the maximum value of the third wavelength range corresponding to the q+1-th distributed bragg reflection layer. For example, taking q=2 as an example, the third wavelength range corresponding to the 2 nd distributed bragg reflection layer may be 480nm to 620nm, and the third wavelength range corresponding to the 1 st distributed bragg reflection layer may be 620nm to 800nm.

Optionally, the third wavelength ranges corresponding to the different distributed bragg reflection layers do not overlap each other, i.e. do not have overlapping intervals. For example, the third wavelength range corresponding to the 2 nd distributed bragg reflection layer may be 480nm to 620nm, and the third wavelength range corresponding to the 1 st distributed bragg reflection layer may be 630nm to 800nm.

Alternatively, the third wavelength ranges corresponding to different distributed bragg reflection layers are different, or the third wavelength ranges thereof may not be identical. That is, the minimum value of the third wavelength range corresponding to the q-th distributed bragg reflection layer may be smaller than the maximum value of the third wavelength range corresponding to the q+1-th distributed bragg reflection layer. For example, the third wavelength range corresponding to a different distributed bragg reflection layer may have a partially overlapping interval. For example, the third wavelength range corresponding to the 2 nd distributed bragg reflection layer may be 480nm to 620nm, and the third wavelength range corresponding to the 1 st distributed bragg reflection layer may be 600nm to 800nm.

In some possible embodiments, the light conversion layer is further configured to convert at least part of the light of the wavelength of the light incident from the side of the optical structure facing away from the cell structure into light of the first wavelength range. The light conversion layer is also for converting light in the fourth wavelength range into light in the second wavelength range, for example. The light in the fourth wavelength range is light incident from the side of the optical structure away from the battery structure, and the fourth wavelength range is at least part of the total wavelengths except the second wavelength range. For example, due to the thickness of the light-absorbing conversion layer and the forbidden bandwidth of the material thereof, the light L41 is first incident on the light-converting layer, wherein a part of the light is converted into light in the second wavelength range by the light-converting layer, and another part of the light is incident on the light-absorbing conversion layer through the light-converting layer. The light L42 is not directly absorbed by the light-absorbing conversion layer, and this light is also directly incident on the light-converting layer. The light conversion layer also converts such light directly incident thereon into light in a second wavelength range. The light conversion layer may convert light incident on the back surface and not sufficiently absorbed by the thin film solar cell and outside its absorbable band into light within its absorbable band. In addition, some of the light converted by the light conversion layer is directed to the cell structure in the propagation direction, and the light directed to the cell structure can be absorbed again by the light absorption conversion layer, so as to improve the output power of the thin film solar cell. However, some of the light converted by the light conversion layer also has a propagation direction away from the cell structure, and the light away from the cell structure may be directly incident on the distributed bragg reflection layer, and the propagation direction of the light is changed by the distributed bragg reflection layer, so that the propagation direction of the light is directed to the cell structure, and is absorbed again by the light absorption conversion layer, so as to improve the output power of the thin film solar cell.

In some possible embodiments, the thin film solar cell further comprises: a second transparent substrate; the optical structure is formed on the second transparent substrate, the battery structure is formed on the first transparent substrate, and the optical structure and the battery structure are bonded by adopting an adhesive material. In this way, the optical structure can be prepared on the second transparent substrate, the battery structure is prepared on the first transparent substrate, and then the optical structure and the battery structure are bonded together by adopting the bonding material, so that the second transparent substrate with the optical structure and the first transparent substrate with the battery structure are bonded together by adopting the bonding material, and the thin film solar cell is formed.

In some possible embodiments, the optical structure may also be arranged directly on the battery structure.

In a second aspect, embodiments of the present application provide a photovoltaic module, which may include: a housing, and the thin film solar cell provided by the embodiment of the application; wherein the thin film solar cell may be located in the housing. Like this, can protect film solar cell through the casing, avoid film solar cell to receive external interference, improve photovoltaic module's reliability and security.

And moreover, the thin film solar cells arranged in the shell are not limited to one, a plurality of thin film solar cells can be arranged, and the specific number of the thin film solar cells can be set according to actual needs so as to improve the power generation of the photovoltaic module.

Further, the electrical connection relationship of the thin film solar cells may be set as: parallel connection, series connection, or a combination of series and parallel connection; the setting can be specifically performed according to actual needs, and is not limited herein.

And a plurality of cell structures in each thin film solar cell are connected in series in sequence. For example, the first conductive layer of one of the two battery structures is connected to the second conductive layer of the other battery structure by a connection portion, corresponding to the adjacent two battery structures. And insulating materials are arranged between the first conductive layers of different battery structures, and insulating materials are also arranged between the second conductive layers of different battery structures. And for the battery structure where the connecting part and the second conductive layer connected with the connecting part are located, insulating materials are arranged between the connecting part and the rest of film layers except the second conductive layer in the battery structure so as to realize the insulating effect.

In a third aspect, embodiments of the present application provide a power generation apparatus, comprising: according to the photovoltaic module and the inverter electrically connected with the photovoltaic module, the direct-current signal output by the photovoltaic module can be converted into the alternating-current signal through the inverter, and then the converted alternating-current signal can be integrated into a power grid for use.

The number of the photovoltaic modules included in the power generation device is not limited to two, and may be one or more, and may be specifically set according to actual needs, which is not limited herein.

In this application embodiment, when photovoltaic module is provided with a plurality ofly, the dc-to-ac converter can be provided with a plurality ofly, and photovoltaic module and dc-to-ac converter one-to-one setting to realize that the dc-to-ac converter carries out conversion to the direct current signal that corresponds the photovoltaic module output of setting, in order to improve the degree of accuracy of conversion.

Of course, when the photovoltaic modules are provided in plurality, one inverter may be provided, not shown, and at this time, the inverter is electrically connected with each photovoltaic module, and at this time, the inverter may perform conversion processing on the dc signals output by each photovoltaic module, so as to reduce the number of inverters, and reduce the manufacturing cost of the power generation device.

In the embodiment of the present application, the power generation device may include, in addition to the photovoltaic module and the inverter, other structures that may be used to implement the functions of the power generation device, which is not limited herein.

In a fourth aspect, an embodiment of the present application provides a method for manufacturing a thin film solar cell, which may include: forming a cell structure on a first transparent substrate; the cell structure is configured to absorb light in a first wavelength range. Forming an optical structure over the cell structure; the optical structure includes: at least one light conversion layer and at least one distributed Bragg reflection layer alternately arranged; the film layer farthest from the cell structure in the optical structure is the distributed Bragg reflection layer; the light conversion layer is used for converting light incident on the battery structure after passing through the battery structure into light in the first wavelength range; the distributed Bragg reflection layer is used for reflecting light incident on the distributed Bragg reflection layer, so that the propagation direction of the reflected light is directed to the cell structure.

In some possible embodiments, the optical structure may be formed directly on the cell structure. In some examples, the forming an optical structure on the cell structure may include: and forming at least one light conversion layer and at least one distributed Bragg reflection layer which are alternately arranged on the battery structure by adopting a film preparation process to form the optical structure.

Taking the material of the light conversion layer as an up-conversion quantum dot material as an example, the process of forming the light conversion layer includes, but is not limited to: first, up-conversion quantum dot material will be mixed: naYF ₄ :Yb ³⁺ :Er ³ SiO of +Quantum dot (average size 20 nm) ₂ The nanoparticle dispersion (the solvent is cyclohexane) is dripped on the surface of the second conductive layer of the battery structure. Wherein the ratio of the concentration of the up-conversion quantum dot material in the dispersing agent to the concentration of the nano particles in the dispersing agent is 0.05, namely the concentration of the up-conversion quantum dot material in the dispersing agent is SiO ₂ The ratio of the concentration of the nanoparticles in the dispersant was 1:20. And then forming the light conversion layer film by adopting a spin coating mode or a blade knife coating mode and the like. Thereafter, the light conversion layer film is cured using a temperature hot stage including, but not limited to, 150 ℃.

Wherein the process of forming the distributed Bragg reflection layer includes, but is not limited to: firstly, siO is adopted by a plasma enhanced chemical vapor deposition method, a magnetron sputtering method, spin coating or blade knife coating method and the like ₂ The solution forms a first refractive index layer. Then, siN is adopted by a plasma enhanced chemical vapor deposition method, a magnetron sputtering method, spin coating or blade knife coating method and the like _x The solution forms a second refractive index layer on the first refractive index layer. Thereafter, the process of preparing the first refractive index layer and the second refractive index layer is repeated to form sequentially repeated first refractive index layer and second refractive index layer to generate SiO ₂ /SiN _x /SiO ₂ /SiN _x ……SiO ₂ /SiN _x Form a distributed bragg reflection layer. The thicknesses of the first refractive index layer and the second refractive index layer are determined according to the central wavelength of the reflected light and the corresponding refractive index.

In some possible embodiments, the optical structure may also be formed on the second transparent substrate. In some examples, before forming the optical structure on the battery structure, the method further comprises: and forming at least one light conversion layer and at least one distributed Bragg reflection layer which are alternately arranged on the second transparent substrate by adopting a film preparation process to form the optical structure. And, the forming an optical structure on the battery structure, comprising: and bonding the side surface of the second transparent substrate with the optical structure to the side surface of the first transparent substrate with the battery structure by adopting an adhesive material.

Taking the material of the light conversion layer as an up-conversion quantum dot material as an example, the process of forming the light conversion layer includes, but is not limited to: first, up-conversion quantum dot material will be mixed: naYF ₄ :Yb ³⁺ :Er ³⁺ SiO of quantum dot (average size 20 nm) ₂ The nanoparticle dispersion liquid (the solvent is cyclohexane) is dripped on the surface of the corresponding film layer. Wherein the ratio of the concentration of the up-conversion quantum dot material in the dispersing agent to the concentration of the nano particles in the dispersing agent is 0.05, namely the concentration of the up-conversion quantum dot material in the dispersing agent is SiO ₂ The ratio of the concentration of the nanoparticles in the dispersant was 1:20. And then forming the light conversion layer film by adopting a spin coating mode or a blade knife coating mode and the like. Thereafter, the light conversion layer film is cured using a temperature hot stage including, but not limited to, 150 ℃.

Wherein the process of forming the distributed Bragg reflection layer includes, but is not limited to: firstly, siN is adopted by a plasma enhanced chemical vapor deposition method, a magnetron sputtering method, spin coating or blade knife coating method and the like _x The solution forms a second refractive index layer. Then adopting SiO by plasma enhanced chemical vapor deposition, magnetron sputtering, spin coating or blade knife coating and other methods ₂ The solution forms a first refractive index layer. Thereafter, the process of preparing the first refractive index layer and the second refractive index layer is repeated to form sequentially repeated first refractive index layer and second refractive index layer to generate SiO ₂ /SiN _x /SiO ₂ /SiN _x ……SiO ₂ /SiN _x Form a distributed bragg reflection layer. Wherein, the firstThe thicknesses of the refractive index layers are determined according to the central wavelength of the reflected light and the corresponding refractive index.

Drawings

Fig. 1 is a schematic structural diagram of a thin film solar cell in the prior art;

fig. 2 is a schematic structural view of another thin film solar cell according to the prior art;

fig. 3 is a schematic structural diagram of a thin film solar cell according to an embodiment of the present application;

FIG. 4 is a schematic diagram of wavelength ranges corresponding to the light conversion layer and the distributed Bragg reflection layer in the embodiment of the present application;

fig. 5 is a schematic structural diagram of a thin film solar cell according to an embodiment of the present application;

fig. 6 is a flowchart of a method for manufacturing a thin film solar cell according to an embodiment of the present application;

fig. 7 is a schematic structural diagram of another thin film solar cell according to an embodiment of the present application;

fig. 8 is a schematic structural diagram of another thin film solar cell according to an embodiment of the present application;

fig. 9 is a schematic structural diagram of another thin film solar cell according to an embodiment of the present application;

fig. 10 is a schematic diagram of a specific structure of another thin film solar cell according to an embodiment of the present application;

Fig. 11 is a schematic structural diagram of a photovoltaic module according to an embodiment of the present application;

fig. 12 is a schematic structural view of a further photovoltaic module according to an embodiment of the present application;

fig. 13 is a schematic structural view of yet another photovoltaic module according to an embodiment of the present application;

fig. 14 is a schematic structural view of a power generation device in an embodiment of the present application.

Reference numerals:

1-a transparent substrate; 2-a first transparent electrode; 3/22-a first charge transport layer; 4/23-light absorbing conversion layer; 5/24-a second charge transport layer; 6-a second transparent electrode; 10-a first transparent substrate; 20-cell structure; 30-an optical structure; 21-a first conductive layer; 25-a second conductive layer; 31-a light conversion layer; a 32/33-distributed Bragg reflection layer; 40-a second transparent substrate; 50-an adhesive material; 60-insulating material; 70-connecting part; a 100-photovoltaic module; 200-an inverter; 300-grid; 321-1/321-2/321-N/331-1/331-2/331-N-first refractive index layer; 322-1/322-2/322-N/332-1/332-2/332-N-second refractive index layer; light in an absorbable wave band in L11-front incident light; light in the non-absorbable band of the L12-front incident light; light in an absorbable band among the L21-back incident light; light in the non-absorbable band of the L22-back incident light; light within the first wavelength range of the L31-front incident light; light outside the first wavelength range of the L32-front incident light; light within the first wavelength range of the L41-back incident light, and light outside the first wavelength range of the L42-back incident light; F1/F2-direction of incidence.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present application more apparent, the present application will be described in further detail with reference to the accompanying drawings.

It should be noted that the same reference numerals in the drawings of the present application denote the same or similar structures, and thus a repetitive description thereof will be omitted. The words expressing the positions and directions described in the present application are described by taking the drawings as an example, but can be changed according to the needs, and all the changes are included in the protection scope of the present application. The drawings of the present application are merely schematic representations, not to scale.

The embodiment of the application provides a thin-film solar cell, a preparation method thereof, a photovoltaic module and power generation equipment, and the thin-film solar cell, the photovoltaic module and the power generation equipment can be applied to various scenes applicable to solar cells such as ground power stations, photovoltaic building integration and the like. In addition, since the embodiment of the application aims at improving the output power of the thin film solar cell, the performance of the photovoltaic module and the power generation equipment formed by adopting the thin film solar cell in the embodiment of the application is also better.

For ease of understanding, reference to the wavelength of light in this application refers to the wavelength of light in vacuum.

Fig. 1 schematically shows a structure of a thin film solar cell according to the related art. Fig. 2 schematically shows a structure of a thin film solar cell according to still another prior art.

Referring to fig. 1 and 2, in the prior art, a bifacial thin film solar cell generally includes: a first transparent electrode 2, a first charge transport layer 3, a light absorbing conversion layer 4, a second charge transport layer 5, and a second transparent electrode 6, which are sequentially disposed on a transparent substrate 1. Where L11 represents light in an absorbable band out of the front-side incident light, L12 represents light in a non-absorbable band out of the front-side incident light, L11 and L12 are incident from one side of the transparent substrate 1 (the directions indicated by the arrows F1 in fig. 1 are the incident directions of L11 and L12), and the light absorption conversion layer 4 generates electron hole pairs after absorbing L11, forming photo-generated carriers, thereby generating a photo-generated current. L21 represents light in an absorbable band of the back-side incident light, L22 represents light in a non-absorbable band of the back-side incident light, L21 and L22 are incident from one side of the second transparent electrode 6 (the directions indicated by arrows F2 in fig. 1 are the incident directions of L21 and L22), and the light absorption conversion layer 4 also generates electron hole pairs after absorbing L21, forming photo-generated carriers, and also generates photo-generated current.

However, referring to fig. 1, since both the front and back surfaces in the bifacial thin film solar cell are transparent electrodes, when the thickness of the light absorption conversion layer 4 is low, there is a case where sufficient absorption is not possible in the absorption bands L11 and L21 (especially, long-band light), resulting in light waste. Further, there are cases where L12 and L22 (e.g., longer wavelength band light) cannot be fully utilized due to factors limited by the forbidden bandwidth of the light absorbing conversion layer material. Whereas there is a lot of longer band light in the front side incident light and the back side incident light. If the wasted light is fully utilized, the output power of the double-sided thin film solar cell can be effectively improved.

In order to make full use of the light, referring to fig. 2, the main method is to increase the thickness of the light absorption conversion layer 4, which means that the optical path length of the incident light in the light absorption conversion layer 4 increases, facilitating the full absorption of the light. However, since the thickness of the light-absorbing conversion layer 4 is increased, the transmission distance of the photogenerated carriers increases, which has a higher requirement for the film quality of the light-absorbing conversion layer 4 and a higher requirement for the carrier diffusion length. When the light absorption conversion layer 4 film has poor quality, especially poor crystallinity, a large number of charge traps caused by defects exist in the light absorption conversion layer 4 film, so that the diffusion distance of carriers is reduced, the improvement of the output power of the battery is not facilitated, and the overall performance of the battery is reduced.

In addition, increasing the thickness of the light absorption conversion layer 4 does not change the forbidden bandwidth of the material, so that light with longer wavelength still has no way to be absorbed and utilized, and a great amount of light waste still exists, which is unfavorable for improving the output power of the battery and further reduces the overall performance of the battery.

The embodiment of the application provides a thin film solar cell, which can improve the optical utilization rate of incident light and the overall output power of the thin film solar cell.

Fig. 3 schematically illustrates a structure of a thin film solar cell according to an embodiment of the present application.

Referring to fig. 3, a thin film solar cell in an embodiment of the present application includes: a first transparent substrate 10, a cell structure 20 on the first transparent substrate 10, and an optical structure 30 on the cell structure 20. The battery structure 20 is configured to absorb light in a first wavelength range, and generate electron-hole pairs by the absorbed light to form photo-generated carriers, thereby generating a photo-generated current. That is, light in the first wavelength range is light within the absorptive wavelength band of the cell structure 20.

Illustratively, the first transparent substrate 10 may include a glass substrate. Of course, the first transparent substrate 10 may be provided as another transparent substrate, which is not limited herein.

Illustratively, referring to fig. 3, the battery structure 20 includes: a first conductive layer 21, a first charge transport layer 22, a light absorbing conversion layer 23, a second charge transport layer 24, and a second conductive layer 25, which are sequentially disposed on the first transparent substrate 10. Alternatively, the materials of the first conductive layer 21 and the second conductive layer 25 may be both transparent conductive materials, and then the thin film solar cell in the embodiment of the present application may include a double-sided thin film solar cell. Where L31 represents light within the first wavelength range among the front-side incident light, L32 represents light outside the first wavelength range among the front-side incident light, L31 and L32 are incident from one side of the first conductive layer 21 (the directions indicated by the arrows F1 in fig. 3 are the incident directions of L31 and L32), and the light absorption conversion layer 23 generates electron hole pairs after absorbing L31 to form photogenerated carriers, thereby generating a photogenerated current. L41 represents light within the first wavelength range among the back-side incident light, L42 represents light outside the first wavelength range among the back-side incident light, L41 and L42 are incident from one side of the second conductive layer 25 (the directions indicated by the arrows F2 in fig. 3 are the incident directions of L41 and L42), and the light absorption conversion layer 23 also generates electron-hole pairs after absorbing L41, forming photogenerated carriers, and also generates photogenerated current.

Illustratively, the optical structure 30 is disposed directly on the battery structure 20, that is, the optical structure 30 is formed directly on the battery structure 20 and is not connected by an adhesive material. Optionally, the optical structure 30 comprises: one or more light conversion layers and one or more distributed Bragg reflection layers, and the light conversion layers and the distributed Bragg reflection layers are alternately arranged in sequence. Fig. 3 illustrates an optical structure 30 comprising a light conversion layer and a distributed bragg reflection layer.

Illustratively, referring to fig. 3, the optical structure 30 includes: a light conversion layer 31 and a distributed bragg reflection layer 32. The light conversion layer 31 is located between the distributed bragg reflection layer 32 and the second conductive layer 25, and the distributed bragg reflection layer 32 is a film layer of the optical structure 30 farthest from the battery structure 20. Wherein the light conversion layer 31 is configured to convert light incident thereon after passing through the cell structure 20 into light in a first wavelength range, and the distributed bragg reflection layer 32 is configured to reflect the light incident thereon such that a propagation direction of the reflected light is directed to the cell structure 20.

Alternatively, the light conversion layer 31 and the distributed bragg reflection layer 32 may be one structural group, and the wavelength range of the light converted by the light conversion layer 31 is located within the wavelength range of the light reflected by the distributed bragg reflection layer 32. For example, the light conversion layer 31 is configured to convert light incident thereon after passing through the cell structure 20 into light in the second wavelength range, and the distributed bragg reflection layer 32 is configured to reflect light in the third wavelength range such that the propagation direction of the reflected light is directed to the cell structure 20. The second wavelength range and the third wavelength range are both within the first wavelength range, and the second wavelength range corresponding to the light conversion layer 31 is within the third wavelength range corresponding to the distributed bragg reflection layer 32.

Referring to fig. 3, due to the thickness of the light-absorbing conversion layer 4 and the forbidden bandwidth of the material thereof, the light L31 may not be sufficiently absorbed by the light-absorbing conversion layer 23 (e.g., the light of the first wavelength middle-long wavelength band may not be sufficiently absorbed by the light-absorbing conversion layer 23), and thus a portion of the light (e.g., the light of the first wavelength middle-long wavelength band) may be incident on the light-converting layer 31 after passing through the battery structure 20. The light L32 is not directly absorbed by the light-absorbing conversion layer 23, and this light is also incident on the light-converting layer 31 after passing through the cell structure 20. The light conversion layer 31 converts the light incident thereon after passing through the cell structure 20 into light in the second wavelength range. Since the second wavelength range is located within the first wavelength range, i.e., the light converted by the light conversion layer 31 can be absorbed by the light absorption conversion layer 23, the light conversion layer 31 can convert light incident on the front side and not sufficiently absorbed by the thin film solar cell and outside its absorbable band into light within its absorbable band. In addition, some of the light converted by the light conversion layer 31 is directed to the cell structure 20 in the propagation direction, and the light directed to the cell structure 20 may be absorbed again by the light absorption conversion layer 23 to increase the output power of the thin film solar cell. However, some of the light converted by the light conversion layer 31 also has a propagation direction away from the cell structure 20, and the light away from the cell structure 20 may be directly incident on the distributed bragg reflection layer 32, and the propagation direction of the light is changed by the distributed bragg reflection layer 32, so that the propagation direction of the light is directed to the cell structure 20, and is absorbed again by the light absorption conversion layer 23, so as to further improve the output power of the thin film solar cell.

The embodiment of the application provides a thin film solar cell, through set up optical structure at the back of thin film solar cell, this optical structure includes light conversion layer and distributed Bragg reflection stratum that set up in turn, light conversion layer can be with the thin film solar cell insufficient absorption and be in its light that can absorb the wave band outside light conversion to its can absorb the wave band within, and through distributed Bragg reflection stratum with the transmission direction adjustment of light that light conversion layer converted out, so that the thin film solar cell absorbs, improve the optical utilization ratio of thin film solar cell's incident light, and improve the utilization ratio of light outside the absorbable wave band of thin film solar cell, and then improve thin film solar cell's overall output.

In an embodiment of the present application, the light conversion layer is further configured to convert at least part of the light of the wavelength of the light incident from the side of the optical structure facing away from the cell structure into light in the first wavelength range. Illustratively, the light conversion layer 31 is also configured to convert light in the fourth wavelength range to light in the second wavelength range. The light in the fourth wavelength range is light incident from the side of the optical structure 30 facing away from the cell structure 20, and the fourth wavelength range is at least part of the total wavelengths except for the second wavelength range. Referring to fig. 3, due to the thickness of the light-absorbing conversion layer 4 and the forbidden bandwidth of the material thereof, light L41 is first incident on the light-converting layer 31, wherein a part of the light is converted into light in the second wavelength range by the light-converting layer 31, and another part of the light is incident on the light-absorbing conversion layer 23 through the light-converting layer 31. The light L42 is not directly absorbed by the light-absorbing conversion layer 23, and a part of the light is also directly incident on the light-converting layer 31. The light conversion layer 31 also converts these light directly incident thereon into light in the second wavelength range. The light conversion layer 31 may convert light that is incident on the back surface and that is insufficiently absorbed by the thin film solar cell and that is outside its absorbable band into light within its absorbable band. In addition, some of the light converted by the light conversion layer 31 is directed to the cell structure 20 in the propagation direction, and the light directed to the cell structure 20 may be absorbed again by the light absorption conversion layer 23 to increase the output power of the thin film solar cell. However, some of the light converted by the light conversion layer 31 also has a propagation direction away from the cell structure 20, and the light away from the cell structure 20 may be directly incident on the distributed bragg reflection layer 32, and the propagation direction of the light is changed by the distributed bragg reflection layer 32, so that the propagation direction of the light is directed to the cell structure 20, and is absorbed again by the light absorption conversion layer 23, so as to improve the output power of the thin film solar cell.

The thin film solar cell provided by the embodiment of the application can be arranged as a double-sided thin film solar cell. The optical structure formed by the light conversion layer and the distributed Bragg reflection layer is adopted on the back surface of the double-sided thin film solar cell to improve the optical utilization of directly incident light and the utilization of light with wavelengths other than absorbable waves, the light with the wavelengths can be converted into light which can be absorbed by the double-sided thin film solar cell after passing through the light conversion layer, and the transmission direction adjustment of the light is realized through the distributed Bragg reflection mirror, so that the overall output power of the double-sided thin film solar cell is improved.

Alternatively, the wavelength range of the light converted by the light conversion layer 31 may be the same as the first wavelength range, i.e., the second wavelength range corresponding to the light conversion layer 31 is the same as the first wavelength range. Alternatively, the wavelength range of the light converted by the light conversion layer 31 may be located within the first wavelength range, that is, the first wavelength range includes the second wavelength range corresponding to the light conversion layer 31. For example, the first wavelength range may be 400nm to 800nm, the second wavelength range corresponding to the light conversion layer 31 may be 500nm to 600nm, or the second wavelength range corresponding to the light conversion layer 31 may be 480nm to 700nm. Of course, in practical applications, the first wavelength range and the second wavelength range may be determined according to requirements of practical applications, which is not limited in this application.

Optionally, fig. 4 schematically illustrates a schematic diagram of wavelength ranges corresponding to the light conversion layer and the distributed bragg reflection layer in the embodiment of the present application. Referring to fig. 4, the second wavelength range (the range of emitted light as shown by the solid line curve in fig. 4) corresponding to the light conversion layer 31 is located within the third wavelength range (the range of reflected light 1 as shown by the broken line frame in fig. 4) corresponding to the distributed bragg reflection layer 32, and the third wavelength range corresponding to the distributed bragg reflection layer 32 is located within the first wavelength range. For example, when the second wavelength range corresponding to the light conversion layer 31 is the same as the first wavelength range, the third wavelength range corresponding to the distributed bragg reflection layer 32 may be the same as the first wavelength range. Alternatively, when the first wavelength range includes the second wavelength range corresponding to the light conversion layer 31, the third wavelength range corresponding to the distributed bragg reflection layer 32 may be made to include the second wavelength range corresponding to the light conversion layer 31. For example, the first wavelength range may be 400nm to 800nm, the second wavelength range corresponding to the light conversion layer 31 may be 500nm to 600nm, and the third wavelength range corresponding to the distributed bragg reflection layer 32 may be 480nm to 620nm. Of course, in practical applications, the first wavelength range, the second wavelength range and the third wavelength range may be determined according to requirements of practical applications, which is not limited in this application.

In some examples, the material of the light conversion layer may include an up-conversion material. Wherein the up-conversion material is for converting light of a wavelength greater than a maximum of the second wavelength range to light in the second wavelength range. The wavelength range of light that can be absorbed by the light conversion layer in this way can include light of a maximum wavelength that is greater than the second wavelength range, thereby converting light of a maximum wavelength that is greater than the second wavelength range into light in the second wavelength range. For example, referring to fig. 4, the up-conversion material is used to convert light having a wavelength greater than 600nm into light in a second wavelength range, while the second wavelength range may be 500nm to 600 nm. Alternatively, referring to fig. 4, the up-conversion material may convert light in the wavelength range of 600nm to 1100nm into light in the second wavelength range, while the second wavelength range may be 500nm to 600 nm.

Illustratively, the material of the light conversion layer may further include: dispersants for dispersing upconverting quantum dot materials, the dispersants comprising nanoparticles (e.g., siO ₂ ) And a solvent, and the ratio between the concentration of the up-conversion quantum dot material in the dispersant and the concentration of the nanoparticle in the dispersant ranges from 0.01 to 0.1. Optionally, the ratio between the concentration of the upconverting quantum dot material in the dispersant and the concentration of the nanoparticle in the dispersant ranges from 0.03 to 0.07. For example, the ratio between the concentration of the upconverting quantum dot material in the dispersant and the concentration of the nanoparticle in the dispersant is 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, etc., without limitation herein.

In other examples, the material of the light conversion layer may include a down conversion material. Wherein the down-conversion material is for converting light of a minimum wavelength less than the second wavelength range to light in the second wavelength range. The wavelength range of light that can be absorbed by the light conversion layer may include light of a minimum wavelength less than the second wavelength range, thereby converting light of a minimum wavelength less than the second wavelength range into light in the second wavelength range. For example, referring to fig. 4, the down-conversion material is used to convert light having a wavelength less than 500nm into light in the second wavelength range, while the second wavelength range may be 500nm to 600 nm. Alternatively, referring to fig. 4, the down-conversion material may convert light in the wavelength range of 200nm to 500nm into light in the second wavelength range, while the second wavelength range may be 500nm to 600 nm.

Illustratively, the down-conversion material includes, but is not limited to, a down-conversion quantum dot material. Optionally, the down-converting quantum dot material includes, but is not limited to: containing rare earthQuantum dots of ions (e.g., without limitation, sr ₂ SiO ₄ :Re ²⁺ ) Vanadate quantum dots, indium phosphide quantum dots, zinc sulfide quantum dots, and perovskite quantum dots (e.g., without limitation, csPbBr ₃ ) At least one of them. Of course, the material system may be adjusted according to the wavelength conversion requirement, and the present application is not limited to the down-conversion material.

Fig. 5 schematically illustrates a specific structure of a thin film solar cell according to an embodiment of the present application. Referring to fig. 5, the distributed bragg reflection layer 32 includes a plurality of first refractive index layers 321-1 to 321-N and a plurality of second refractive index layers 322-1 to 322-N, the number of the first refractive index layers and the number of the second refractive index layers are the same, and the plurality of first refractive index layers 321-1 to 321-N and the plurality of second refractive index layers 322-1 to 322-N are alternately arranged, i.e., the first refractive index layers 321-1 are in direct contact with the light conversion layer 31, the second refractive index layers 322-1 are located on the first refractive index layers 321-1, and the first refractive index layers 321-2 are located on the second refractive index layers 322-1. The rest of the same are analogous to each other, and are not described in detail herein.

And the refractive index of the first refractive index layer is larger than that of the second refractive index layer adjacent to the first refractive index layer. For example, the refractive index of the first refractive index layer 321-2 is greater than the refractive index of the second refractive index layer 322-1 and the refractive index of the second refractive index layer 322-2. The rest of the same are analogous to each other, and are not described in detail herein. Thus, the distributed Bragg reflection layer 32 may be formed by sequentially repeating the first refractive index layer and the second refractive index layer.

The specific numerical value of N is not limited in this application, and may be determined according to the requirements of practical applications.

In some examples, each of the plurality of first refractive index layers is the same in the same distributed bragg reflection layer. Thus, the design difficulty can be reduced, and the preparation difficulty can be reduced.

In other examples, the refractive index of the first refractive index layer of the plurality of first refractive index layers may be sequentially increased in the same distributed bragg reflection layer in the direction (the direction indicated by the arrow of F1) directed to the cell structure 20 by the first transparent substrate 10. Alternatively, in the same distributed bragg reflection layer in the direction (the direction indicated by the arrow of F1) in which the first transparent substrate 10 is directed toward the cell structure 20, the refractive index of the first refractive index layer among the plurality of first refractive index layers may be sequentially reduced. This allows the refractive indices of the different first refractive index layers to be adjustable.

In some examples, each of the plurality of second refractive index layers is the same in the same distributed bragg reflection layer. Thus, the design difficulty can be reduced, and the preparation difficulty can be reduced.

In other examples, in the same distributed bragg reflection layer in the direction (the direction indicated by the arrow of F1) directed toward the cell structure 20 by the first transparent substrate 10, the refractive index of the second refractive index layer of the plurality of second refractive index layers sequentially increases. Alternatively, in the same distributed bragg reflection layer in the direction (the direction indicated by the arrow of F1) directed toward the cell structure 20 by the first transparent substrate 10, the refractive index of the second refractive index layer of the plurality of second refractive index layers sequentially decreases. This allows the refractive index of the different second refractive index layer to be adjustable.

Fig. 6 is a flowchart illustrating a method for manufacturing a thin film solar cell according to an embodiment of the present application. Referring to fig. 6, a method for manufacturing a thin film solar cell according to an embodiment of the present application includes:

s10, forming a battery structure on the first transparent substrate. Wherein the cell structure is configured to absorb light in a first wavelength range.

In some examples, referring to fig. 5, a first conductive layer 21, a first charge transport layer 22, a light absorbing conversion layer 23, a second charge transport layer 24, and a second conductive layer 25 may be sequentially formed on the first transparent substrate 10 using a manufacturing method in the related art.

Alternatively, the first conductive layer 21 and the second conductive layer 25 may each be provided as a transparent conductive material. For example, the transparent conductive material may be a transparent conductive oxide (Transparent conductive oxide, TCO, alternatively, the transparent conductive material may be Indium Tin Oxide (ITO). Specific materials of the transparent conductive material are not limited herein, and may be determined according to the needs of practical applications, and are not limited herein.

In the embodiment of the application, the thin film solar cell may be: the material of the light absorption conversion layer may be selected according to the specific application form of the thin film solar cell, and is not limited herein.

S20, forming an optical structure on the battery structure. Wherein the optical structure comprises: at least one light conversion layer and at least one distributed Bragg reflection layer alternately arranged; the film layer of the optical structure furthest from the cell structure is a distributed Bragg reflection layer. Wherein, at least one light conversion layer and at least one distributed Bragg reflection layer which are alternately arranged can be formed on the cell structure by adopting a film preparation process to form an optical structure.

In some examples, taking the example that the light conversion layer includes an up-conversion quantum dot material, step S20 includes:

first, referring to fig. 5, a light conversion layer 31 is formed on the surface of the second conductive layer 25 using an up-conversion quantum dot material using a thin film fabrication process. Illustratively, first, the upconverting quantum dot material will be mixed: naYF ₄ :Yb ³⁺ :Er ³⁺ SiO of quantum dot (average size 20 nm) ₂ The nanoparticle dispersion (cyclohexane as solvent) is dropped onto the surface of the second conductive layer 25. Wherein the ratio of the concentration of the up-conversion quantum dot material in the dispersing agent to the concentration of the nano particles in the dispersing agent is 0.05, namely the concentration of the up-conversion quantum dot material in the dispersing agent is SiO ₂ The ratio of the concentration of the nanoparticles in the dispersant was 1:20. And then forming the light conversion layer film by adopting a spin coating mode or a blade knife coating mode and the like. Thereafter, the light conversion layer film is cured using a temperature hot stage including, but not limited to, 150 ℃.

Thereafter, referring to fig. 5, a distributed bragg reflection layer 32 is formed on the light conversion layer 31 using a thin film fabrication process. Illustratively, first, siO is employed by plasma enhanced chemical vapor deposition, magnetron sputtering, spin coating, or blade knife coating ₂ The solution forms the first refractive index layer 321-1 on the light conversion layer 31. Then, siN is adopted by a plasma enhanced chemical vapor deposition method, a magnetron sputtering method, spin coating or blade knife coating method and the like _x The solution forms a second refractive index layer 322-1 on the first refractive index layer 321-1. Thereafter, the process of preparing the first refractive index layer 321-1 and the second refractive index layer 322-1 is repeated to form sequentially repeated first refractive index layer and second refractive index layer to generate SiO ₂ /SiN _x /SiO ₂ /SiN _x ……SiO ₂ /SiN _x Is formed as a distributed bragg reflector layer 32. The thicknesses of the first refractive index layer and the second refractive index layer are determined according to the central wavelength of the reflected light and the corresponding refractive index.

Fig. 7 schematically illustrates a structure of another thin film solar cell in an embodiment of the present application. Fig. 8 schematically illustrates a specific structure of another thin film solar cell in an embodiment of the present application.

Referring to fig. 7 and 8, in the present embodiment, the thin film solar cell includes: a first transparent substrate 10, a cell structure 20 on the first transparent substrate 10, and an optical structure 30 on the cell structure 20. The present embodiment is modified from the embodiment modes in the above embodiments. Only the differences between the present embodiment and the above-described embodiments are described below, and their details are not repeated here.

In an embodiment of the present application, referring to fig. 7 and 8, the optical structure 30 includes: a distributed bragg reflection layer 33, a light conversion layer 31, and a distributed bragg reflection layer 32. Wherein the distributed bragg reflection layer 33 is in direct contact with the second conductive layer 25, and the light conversion layer 31 is located between the distributed bragg reflection layer 33 and the distributed bragg reflection layer 32.

Illustratively, the third wavelength range corresponding to the different distributed bragg reflection layers is different. For example, the third wavelength range corresponding to the distributed bragg reflection layer 33 is different from the third wavelength range corresponding to the distributed bragg reflection layer 32.

Alternatively, the third wavelength ranges corresponding to different distributed bragg reflection layers may be different from each other. For example, the third wavelength range corresponding to a different distributed bragg reflection layer may have a partially overlapping interval. For example, the third wavelength range corresponding to the distributed Bragg reflection layer 32 may be 480nm to 620nm, and the third wavelength range corresponding to the distributed Bragg reflection layer 33 may be 600nm to 800nm.

Optionally, in a direction (a direction indicated by an arrow F1) in which the first transparent substrate 10 points to the cell structure 20, the plurality of distributed bragg reflection layers are defined as a 1 st distributed bragg reflection layer to a Q-th distributed bragg reflection layer, and a minimum value of the third wavelength range corresponding to the Q-th distributed bragg reflection layer is not greater than a maximum value of the third wavelength range corresponding to the q+1-th distributed bragg reflection layer. Wherein Q is an integer greater than 1, and Q is an integer greater than or equal to 1 and less than or equal to Q. The specific values of Q are not limited in this application.

Illustratively, the minimum value of the third wavelength range corresponding to the q-th distributed bragg reflection layer is equal to the maximum value of the third wavelength range corresponding to the q+1-th distributed bragg reflection layer. In this application, q=2 is taken as an example. For example, referring to fig. 4, the third wavelength range (the range of reflected light 1 shown by the dashed-line box in fig. 4) corresponding to the distributed bragg reflection layer 32 (i.e., the 2 nd distributed bragg reflection layer) may be 480nm to 620nm, and the third wavelength range (the range of reflected light 2 shown by the dashed-line box in fig. 4) corresponding to the distributed bragg reflection layer 33 (i.e., the 1 st distributed bragg reflection layer) may be 620nm to 800nm.

Optionally, the third wavelength ranges corresponding to the different distributed bragg reflection layers do not overlap each other, i.e. do not have overlapping intervals. For example, the third wavelength range corresponding to the distributed Bragg reflection layer 32 may be 480nm to 620nm, and the third wavelength range corresponding to the distributed Bragg reflection layer 33 may be 630nm to 800nm.

Alternatively, the third wavelength ranges corresponding to different distributed bragg reflection layers are different, or the third wavelength ranges thereof may not be identical. That is, the minimum value of the third wavelength range corresponding to the q-th distributed bragg reflection layer may be smaller than the maximum value of the third wavelength range corresponding to the q+1-th distributed bragg reflection layer. For example, the third wavelength range corresponding to a different distributed bragg reflection layer may have a partially overlapping interval. For example, the third wavelength range corresponding to the distributed bragg reflection layer 32 (i.e., the 2 nd distributed bragg reflection layer) may be 480nm to 620nm, and the third wavelength range corresponding to the distributed bragg reflection layer 33 (i.e., the 1 st distributed bragg reflection layer) may be 600nm to 800nm.

Referring to fig. 7, due to the thickness of the light-absorbing conversion layer 4 and the forbidden bandwidth of the material thereof, the light L31 may not be sufficiently absorbed by the light-absorbing conversion layer 23 (for example, the light in the middle-long wavelength band of the first wavelength is not sufficiently absorbed by the light-absorbing conversion layer 23), and this part of the light may directly enter the distributed bragg reflection layer 33, and the propagation direction of the light is changed by the reflection of the distributed bragg reflection layer 33, so that the propagation direction of the light is directed to the cell structure 20 and is again absorbed by the light-absorbing conversion layer 23. The light L32 is not directly absorbed by the light-absorbing conversion layer 23, and this light is incident on the light-converting layer 31. The light conversion layer 31 converts these light into light in the second wavelength range. The light conversion layer 31 may convert light incident on the front surface and not sufficiently absorbed by the thin film solar cell and outside its absorbable band into light within its absorbable band. In addition, some of the light converted by the light conversion layer 31 is directed to the cell structure 20 in the propagation direction, and the light directed to the cell structure 20 may be absorbed again by the light absorption conversion layer 23 to increase the output power of the thin film solar cell. However, some of the light converted by the light conversion layer 31 also has a propagation direction away from the cell structure 20, and the light away from the cell structure 20 may be directly incident on the distributed bragg reflection layer 32, and the propagation direction of the light is changed by the distributed bragg reflection layer 32, so that the propagation direction of the light is directed to the cell structure 20, and is absorbed again by the light absorption conversion layer 23, so as to improve the output power of the thin film solar cell.

Referring to fig. 7, due to the thickness of the light-absorbing conversion layer 4 and the forbidden bandwidth of the material thereof, a part of the light L41 is incident on the light-converting layer 31, the light-converting layer 31 converts the light into light in the second wavelength range, and a part may be incident into the light-absorbing conversion layer 23 through the light-converting layer 31. The light L42 is not directly absorbed by the light-absorbing conversion layer 23, and this light is incident on the light-converting layer 31. The light conversion layer 31 converts these light into light in the second wavelength range. The light conversion layer 31 may convert light that is incident on the back surface and that is insufficiently absorbed by the thin film solar cell and that is outside its absorbable band into light within its absorbable band. In addition, some of the light converted by the light conversion layer 31 is directed to the cell structure 20 in the propagation direction, and the light directed to the cell structure 20 may be absorbed again by the light absorption conversion layer 23 to increase the output power of the thin film solar cell. However, some of the light converted by the light conversion layer 31 also has a propagation direction away from the cell structure 20, and the light away from the cell structure 20 may be directly incident on the distributed bragg reflection layer 32, and the propagation direction of the light is changed by the distributed bragg reflection layer 32, so that the propagation direction of the light is directed to the cell structure 20, and is absorbed again by the light absorption conversion layer 23, so as to improve the output power of the thin film solar cell.

In the embodiment of the present application, the distributed bragg reflection layer 32 includes a plurality of first refractive index layers 321-1 to 321-N and a plurality of second refractive index layers 322-1 to 322-N that are alternately disposed, and the implementation manner thereof may refer to the above embodiment and will not be described herein.

Illustratively, referring to FIGS. 7 and 8, the distributed Bragg reflection layer 33 includes a plurality of first refractive index layers 321-1 to 321-K and a plurality of second refractive index layers 322-1 to 322-K alternately arranged. Wherein the number of the first refractive index layers is the same as the number of the second refractive index layers, and the plurality of first refractive index layers 321-1 to 321-K and the plurality of second refractive index layers 322-1 to 322-K are alternately arranged, that is, the first refractive index layer 331-1 is in direct contact with the second conductive layer 25, the second refractive index layer 332-1 is located on the first refractive index layer 331-1, and the first refractive index layer 331-2 is located on the second refractive index layer 332-1. The rest of the same are analogous to each other, and are not described in detail herein. And the first refractive index of the first refractive index layer is larger than the second refractive index of the second refractive index layer adjacent to the first refractive index layer. For example, the first refractive index of the first refractive index layer 331-2 is greater than the second refractive index of the second refractive index layer 332-1 and the second refractive index of the second refractive index layer 332-2. The rest of the same are analogous to each other, and are not described in detail herein. Thus, the distributed bragg reflection layer 33 can be formed by sequentially repeating the first refractive index layer and the second refractive index layer.

The specific numerical value of K is not limited in this application, and may be determined according to the requirements of practical applications.

In this embodiment, the first refractive index layers 321-1 to 321-K and the second refractive index layers 322-1 to 322-K in the distributed bragg reflection layer 33 may be referred to as the implementation of the first refractive index layers 321-1 to 321-N and the second refractive index layers 322-1 to 322-N in the above embodiment, and will not be described herein.

The bandwidth (e.g., the third wavelength range) of the reflected light reflected by the distributed bragg reflection layers 32 and 33 may be determined by the refractive index difference of the materials of the first refractive index layer and the second refractive index layer. For example, the larger its refractive index difference, the larger the bandwidth of the reflected light.

Taking the structure shown in fig. 8 as an example, a corresponding flow chart of the preparation method can be referred to fig. 6. Wherein, step S10 can refer to the description of the preparation method described above.

Step S20 is: an optical structure is formed over the cell structure.

first, referring to fig. 8, a distributed bragg reflection layer 33 is formed on the second conductive layer 25 using a thin film fabrication process. Illustratively, first, siO is employed by plasma enhanced chemical vapor deposition, magnetron sputtering, spin coating, or blade knife coating ₂ The solution forms the first refractive index layer 331-1 on the second conductive layer 25. Then, siN is adopted by a plasma enhanced chemical vapor deposition method, a magnetron sputtering method, spin coating or blade knife coating method and the like _x The solution forms a second refractive index layer 332-1 on the first refractive index layer 331-1. Thereafter, the process of preparing the first refractive index layer 331-1 and the second refractive index layer 332-1 is repeated to form sequentially repeated first refractive index layer and second refractive index layer to generate SiO ₂ /SiN _x /SiO ₂ /SiN _x ……SiO ₂ /SiN _x Is formed, the distributed bragg reflection layer 33 is formed. The thicknesses of the first refractive index layer and the second refractive index layer are determined according to the central wavelength of the reflected light and the corresponding refractive index.

Thereafter, referring to fig. 8, a light conversion layer 31 is formed on the surface of the second refractive index layer 332-K using an up-conversion quantum dot material using a thin film fabrication process. Illustratively, first, the upconverting quantum dot material will be mixed: naYF ₄ :Yb ³⁺ :Er ³⁺ SiO of quantum dot (average size 20 nm) ₂ The nanoparticle dispersion (cyclohexane solvent) was added dropwise to the surface of the second refractive index layer 332-K. Wherein the ratio of the concentration of the up-conversion quantum dot material in the dispersing agent to the concentration of the nano particles in the dispersing agent is 0.05, namely the up-conversion quantum dot material Concentration in dispersant SiO ₂ The ratio of the concentration of the nanoparticles in the dispersant was 1:20. And then forming the light conversion layer film by adopting a spin coating mode or a blade knife coating mode and the like. Thereafter, the light conversion layer film is cured using a temperature hot stage including, but not limited to, 150 ℃.

Thereafter, referring to fig. 8, a distributed bragg reflection layer 32 is formed on the light conversion layer 31 using a thin film fabrication process. Illustratively, first, siO is employed by plasma enhanced chemical vapor deposition, magnetron sputtering, spin coating, or blade knife coating ₂ The solution forms the first refractive index layer 321-1 on the light conversion layer 31. Then, siN is adopted by a plasma enhanced chemical vapor deposition method, a magnetron sputtering method, spin coating or blade knife coating method and the like _x The solution forms a second refractive index layer 322-1 on the first refractive index layer 321-1. Thereafter, the process of preparing the first refractive index layer 321-1 and the second refractive index layer 322-1 is repeated to form sequentially repeated first refractive index layer and second refractive index layer to generate SiO ₂ /SiN _x /SiO ₂ /SiN _x ……SiO ₂ /SiN _x Is formed as a distributed bragg reflector layer 32. The thicknesses of the first refractive index layer and the second refractive index layer are determined according to the central wavelength of the reflected light and the corresponding refractive index.

Fig. 9 schematically illustrates a structure of still another thin film solar cell in an embodiment of the present application. Fig. 10 schematically illustrates a specific structure of still another thin film solar cell in an embodiment of the present application.

Referring to fig. 9 and 10, in the present embodiment, the thin film solar cell includes: a first transparent substrate 10, a cell structure 20 on the first transparent substrate 10, and an optical structure 30 on the cell structure 20. Wherein the optical structure 30 comprises: a distributed bragg reflection layer 33, a light conversion layer 31, and a distributed bragg reflection layer 32. The present embodiment is modified from the embodiment modes in the above embodiments. Only the differences between the present embodiment and the above-described embodiments are described below, and their details are not repeated here.

Referring to fig. 9 and 10, in the present embodiment, the thin film solar cell further includes: a second transparent substrate 40. The optical structure 30 is formed on the second transparent substrate 40, the cell structure 20 is formed on the first transparent substrate 10, and the optical structure 30 and the cell structure 20 are bonded together with an adhesive material 50. In this way, the optical structure 30 may be prepared on the second transparent substrate 40, the cell structure 20 may be prepared on the first transparent substrate 10, and then the optical structure 30 and the cell structure 20 may be bonded together by using the bonding material 50, that is, using the bonding material 50, the surface of the second transparent substrate 40 having the optical structure 30 may be bonded to the surface of the first transparent substrate 10 having the cell structure 20, so that the second transparent substrate 40 having the optical structure 30 and the first transparent substrate 10 having the cell structure 20 may be bonded together to form the thin film solar cell.

Illustratively, the second transparent substrate 40 may include a glass substrate. Of course, the second transparent substrate 40 may be provided as another transparent substrate, which is not limited herein.

Taking the structure shown in fig. 10 as an example, a flow chart of a corresponding preparation method can be referred to fig. 6. Wherein, step S10 can refer to the description of the preparation method described above.

Before step S20, further includes: the optical structure 30 is formed by alternately disposing at least one light conversion layer and at least one distributed bragg reflection layer on the second transparent substrate 40 using a thin film fabrication process. This process may be performed simultaneously with step S10, or may be performed before step S10, and is not limited herein.

First, referring to fig. 10, a distributed bragg reflection layer 32 is formed on a second transparent substrate 40 using a thin film fabrication process. Illustratively, first, siN is used by plasma enhanced chemical vapor deposition, magnetron sputtering, spin coating, or blade knife coating _x The solution forms a second refractive index layer 322-N on the second transparent substrate 40. Then adopting SiO by plasma enhanced chemical vapor deposition, magnetron sputtering, spin coating or blade knife coating and other methods ₂ The solution forms a first refractive index layer 321-N on a second refractive index layer 322-N. Thereafter, the first refractive index layer 331-Nth is repeatedly preparedA process of forming a first refractive index layer and a second refractive index layer repeatedly appearing in order to appear SiO ₂ /SiN _x /SiO ₂ /SiN _x ……SiO ₂ /SiN _x Is formed as a distributed bragg reflector layer 32. The thicknesses of the first refractive index layer and the second refractive index layer are determined according to the central wavelength of the reflected light and the corresponding refractive index.

Thereafter, referring to fig. 10, a light conversion layer 31 is formed on the surface of the first refractive index layer 321-1 using an up-conversion quantum dot material using a thin film fabrication process. Illustratively, first, the upconverting quantum dot material will be mixed: naYF ₄ :Yb ³⁺ :Er ³⁺ SiO of quantum dot (average size 20 nm) ₂ The nanoparticle dispersion (cyclohexane solvent) was dropped onto the surface of the first refractive index layer 321-1. Wherein the ratio of the concentration of the up-conversion quantum dot material in the dispersing agent to the concentration of the nano particles in the dispersing agent is 0.05, namely the concentration of the up-conversion quantum dot material in the dispersing agent is SiO ₂ The ratio of the concentration of the nanoparticles in the dispersant was 1:20. And then forming the light conversion layer film by adopting a spin coating mode or a blade knife coating mode and the like. Thereafter, the light conversion layer film is cured using a temperature hot stage including, but not limited to, 150 ℃.

Thereafter, referring to fig. 10, a distributed bragg reflection layer 33 is formed on the light conversion layer 31 using a thin film fabrication process. Illustratively, first, siO is employed by plasma enhanced chemical vapor deposition, magnetron sputtering, spin coating, or blade knife coating ₂ The solution forms the second refractive index layer 332-K on the light conversion layer 31. Then, siN is adopted by a plasma enhanced chemical vapor deposition method, a magnetron sputtering method, spin coating or blade knife coating method and the like _x The solution forms the first refractive index layer 331-K on the second refractive index layer 332-K. Thereafter, the process of preparing the first refractive index layer 321-K and the second refractive index layer 322-K is repeated to form sequentially repeated first refractive index layer and second refractive index layer to generate SiO ₂ /SiN _x /SiO ₂ /SiN _x ……SiO ₂ /SiN _x Form a distributed Bragg structureA reflective layer 33. The thicknesses of the first refractive index layer and the second refractive index layer are determined according to the central wavelength of the reflected light and the corresponding refractive index.

Step S20 is: an optical structure is formed over the cell structure.

In some examples, step S20 includes: referring to fig. 10, the side surface of the second transparent substrate 40 having the optical structure 30 is adhered to the side surface of the first transparent substrate 10 having the battery structure 20 using the adhesive material 50.

Fig. 11 schematically illustrates a structure of a photovoltaic module according to an embodiment of the present application. Fig. 12 schematically illustrates a structure of yet another photovoltaic module in an embodiment of the present application. Fig. 13 schematically illustrates a structure of yet another photovoltaic module in an embodiment of the present application.

Referring to fig. 11 to 13, the embodiment of the present application further provides a photovoltaic module, which may include: a housing and the thin film solar cell provided by the embodiment of the application; wherein the thin film solar cell may be located in the housing; like this, can protect film solar cell through the casing, avoid film solar cell to receive external interference, improve photovoltaic module's reliability and security.

The number of the thin film solar cells in the housing is not limited to one, and may be plural, and the number of the thin film solar cells in the housing may be set according to actual needs, so as to increase the power generation of the power generation device. The electrical connection relationship between these thin film solar cells may be set as: parallel connection, series connection, or a combination of series and parallel connection. The setting can be specifically performed according to actual needs, and is not limited herein.

For example, referring to fig. 11 to 13, the number of cell structures 20 in each thin film solar cell is plural, and the plurality of cell structures 20 are sequentially connected in series. For example, the first conductive layer 21 of one cell structure 20 and the second conductive layer 25 of the other cell structure 20 are connected by the connection portion 70 corresponding to the adjacent two cell structures 20. The insulating material 60 is provided between the first conductive layers 21 of the different cell structures 20, and the insulating material 60 is provided between the second conductive layers 25 of the different cell structures 20. And, for the connection part 70 and the battery structure 20 where the second conductive layer 25 connected with the connection part 70 is located, the connection part 70 also has an insulating material 60 with the rest of the film layers except the second conductive layer 25 in the battery structure 20, so as to realize the insulating effect thereof.

For example, referring to fig. 11 to 13, the implementation of the optical structure 30 may refer to the above-mentioned embodiments, and will not be described herein.

Fig. 14 exemplarily shows a schematic structural diagram of a power generation apparatus in an embodiment of the present application. Referring to fig. 14, a power generation apparatus provided in an embodiment of the present application may include: according to the photovoltaic module 100 and the inverter 200 electrically connected with the photovoltaic module 100 provided in the embodiments of the present application, the dc signal output by the photovoltaic module 100 can be converted into the ac signal by the inverter 200, and then the converted ac signal can be integrated into the power grid 300 for use.

The number of the photovoltaic modules 100 included in the power generation apparatus is not limited to two as shown in fig. 14, but may be one or more, and may be specifically set according to actual needs, which is not limited herein.

In this embodiment, as shown in fig. 14, when a plurality of photovoltaic modules 100 are provided, a plurality of inverters 200 may be provided, and the photovoltaic modules 100 and the inverters 200 are set in a one-to-one correspondence manner, so as to implement conversion processing of the dc signals output by the photovoltaic modules 100 that are set correspondingly by the inverters 200, so as to improve the accuracy of conversion.

In embodiments of the present application, the power generation device may be, but is not limited to, a ground power station or a photovoltaic building integrated device.

While preferred embodiments of the present application have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiments and all such alterations and modifications as fall within the scope of the application.

It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments of the present application without departing from the spirit and scope of the embodiments of the present application. Thus, if such modifications and variations of the embodiments of the present application fall within the scope of the claims and the equivalents thereof, the present application is intended to encompass such modifications and variations.

Claims

1. A thin film solar cell, comprising:

a first transparent substrate;

a cell structure on the first transparent substrate, the cell structure for absorbing light in a first wavelength range;

an optical structure on a side of the cell structure facing away from the first transparent substrate, the optical structure comprising: at least one light conversion layer and at least one distributed Bragg reflection layer alternately arranged; the film layer farthest from the cell structure in the optical structure is the distributed Bragg reflection layer;

The light conversion layer is used for converting light incident on the battery structure after passing through the battery structure into light in the first wavelength range;

the distributed Bragg reflection layer is used for reflecting light incident on the distributed Bragg reflection layer, so that the propagation direction of the reflected light is directed to the cell structure.

2. The thin film solar cell of claim 1, wherein the distributed bragg reflector layer comprises a plurality of first refractive index layers and a plurality of second refractive index layers; the refractive index of the first refractive index layer is larger than that of the adjacent second refractive index layer;

the plurality of first refractive index layers and the plurality of second refractive index layers are alternately arranged, and the distributed Bragg reflection layer is in contact with the light conversion layer through the first refractive index layers.

3. The thin film solar cell of claim 2, wherein the refractive indices of the plurality of first refractive index layers are the same in the same distributed bragg reflector layer;

and/or, in the same distributed bragg reflection layer, the refractive indexes of the plurality of second refractive index layers are the same.

4. The thin film solar cell of any one of claims 1-3, wherein adjacent distributed bragg reflection layers and the light conversion layer are used as a structural group, and the distributed bragg reflection layers in the same structural group are positioned on one side of the light conversion layer away from the cell structure;

In the same structure group, the wavelength range of the light converted by the light conversion layer is within the wavelength range of the light reflected by the distributed Bragg reflection layer.

5. The thin film solar cell of any one of claims 1-4, wherein when the optical structure comprises a plurality of distributed bragg reflector layers, the wavelength range of light reflected by different ones of the distributed bragg reflector layers is different.

6. The thin film solar cell of claim 5, wherein the plurality of distributed bragg reflection layers are defined as a 1 st distributed bragg reflection layer to a Q-th distributed bragg reflection layer in a direction directed to the cell structure by the first transparent substrate, a minimum value of a wavelength range of light reflected by the Q-th distributed bragg reflection layer being not more than a maximum value of a wavelength range of light reflected by the q+1th distributed bragg reflection layer;

q is an integer greater than 1, and Q is an integer greater than or equal to 1 and less than or equal to Q.

7. The thin film solar cell of any one of claims 1-6, wherein the light conversion layer is further configured to: at least part of the light of the wavelength of the light incident from the side of the optical structure facing away from the cell structure is converted into light of the first wavelength range.

8. The thin film solar cell according to any one of claims 1 to 7, wherein a wavelength range of the light converted by the light conversion layer is a second wavelength range;

the material of the light conversion layer includes: up-converting material and/or down-converting material;

the up-conversion material is used for: converting light of a wavelength greater than a maximum of the second wavelength range to light in the second wavelength range;

the down-conversion material is used for: light of a wavelength less than the minimum of the second wavelength range is converted into light in the second wavelength range.

9. The thin film solar cell of any one of claims 1-8, further comprising: a second transparent substrate; the optical structure is formed on the second transparent substrate, the battery structure is formed on the first transparent substrate, and the optical structure and the battery structure are bonded by adopting an adhesive material.

10. The thin film solar cell of any one of claims 1-9, wherein the thin film solar cell comprises a bifacial thin film solar cell.

11. A photovoltaic module, comprising: a housing, a thin film solar cell as claimed in any one of claims 1 to 10; the thin film solar cell is arranged in the shell;

The thin film solar cell comprises a plurality of cell structures, and the cell structures are sequentially connected in series.

12. A power generation apparatus, characterized by comprising: the photovoltaic module of claim 11, an inverter electrically connected to the photovoltaic module;

the inverter is used for converting direct current signals output by the photovoltaic module into alternating current signals.

13. A method of manufacturing a thin film solar cell, comprising:

forming a cell structure on a first transparent substrate; the cell structure is configured to absorb light in a first wavelength range;

forming an optical structure over the cell structure; the optical structure includes: at least one light conversion layer and at least one distributed Bragg reflection layer alternately arranged; the film layer farthest from the cell structure in the optical structure is the distributed Bragg reflection layer; the light conversion layer is used for converting light incident on the battery structure after passing through the battery structure into light in the first wavelength range; the distributed Bragg reflection layer is used for reflecting light incident on the distributed Bragg reflection layer, so that the propagation direction of the reflected light is directed to the cell structure.

14. The method of manufacturing of claim 13, wherein forming an optical structure on the cell structure comprises:

And forming at least one light conversion layer and at least one distributed Bragg reflection layer which are alternately arranged on the battery structure by adopting a film preparation process to form the optical structure.

15. The method of manufacturing of claim 13, wherein prior to forming the optical structure on the cell structure, further comprising:

forming at least one light conversion layer and at least one distributed Bragg reflection layer which are alternately arranged on a second transparent substrate by adopting a film preparation process to form the optical structure;

the forming an optical structure on the cell structure, comprising:

and bonding the side surface of the second transparent substrate with the optical structure to the side surface of the first transparent substrate with the battery structure by adopting an adhesive material.