Solar cell, preparation method thereof and photovoltaic module
Patent Information
- Application Number
- CN202411299302.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-18
- Publication Date
- 2025-01-28
AI Technical Summary
There are shortcomings in the use of light in existing solar cells, especially the light transmittance at wavelengths of 900-1200 nm, which leads to the incoming light being unable to be effectively utilized.
在太阳能电池的第二透明导电层上形成由反射层和上转换发光材料层组成的复合膜层，反射层采用光子晶体结构，上转换发光材料层捕获和转换穿过太阳能电池的长波段光。
The utilization rate of solar batteries on long-band incident light is enhanced, the ups and downside strength is enhanced, the short-circuit current density is increased, and the test error brought by the reflection of the copper platform reflection of the I-V test instrument is reduced.
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Figure CN119384099A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the technical field of solar cells, and in particular to a solar cell and a preparation method thereof, and a photovoltaic module. Background Art
[0002] Against the backdrop of growing global energy demand and increasingly severe environmental problems, the development and utilization of solar energy as a clean, renewable energy source has attracted much attention. At present, the mainstream technology of photovoltaic cells will complete the transition from P-type cells to N-type cells. As one of the mainstream technologies of N-type cells, the efficiency of heterojunction cells is restricted by many factors. As far as the light absorption layer is concerned, the unsatisfactory material quality is one of the important reasons for optical loss and limiting cell efficiency.
[0003] From the perspective of material quality, if the material of the light absorption layer has a large number of crystal defects, impurities or uneven distribution of components, this will seriously affect its ability to capture and convert photons. Crystal defects will become the recombination center of carriers, causing photogenerated carriers to recombine before they are effectively collected and cannot be converted into electrical energy output. Some commonly used semiconductor materials have a limited absorption range for sunlight and cannot fully utilize sunlight, resulting in a large amount of light not being converted, including front reflection, parasitic absorption, transmission and scattering.
[0004] From an optical point of view, solar cells have the following shortcomings: the current solar cell structure has certain shortcomings in light utilization, and light with a wavelength of 900-1200nm directly passes through the cell, resulting in the incident light not being effectively utilized. Research results show that the light transmittance of 900-1200nm wavelength is as high as 50%, so how to improve the cell's utilization of long-wavelength incident light is one of the problems currently solved by solar cells. Summary of the invention
[0005] The present disclosure provides a solar cell and a preparation method thereof, and a photovoltaic module, so as to at least solve the above technical problems existing in the prior art.
[0006] According to a first aspect of the present disclosure, a solar cell is provided, comprising:
[0007] A semiconductor substrate, the semiconductor substrate comprising a front side and a back side arranged opposite to each other;
[0008] The semiconductor substrate is provided with a first intrinsic amorphous silicon layer, a first doped layer, a first transparent conductive layer and a first metal electrode in sequence from the front side upward, and a second intrinsic amorphous silicon layer, a second doped layer, a second transparent conductive layer and a second metal electrode in sequence from the back side downward;
[0009] A composite film layer, wherein the composite film layer is located on an area of the second transparent conductive layer that is not covered by the second metal electrode, and the composite film layer comprises an upconversion luminescent material layer and a reflective layer, wherein the reflective layer is a photonic crystal structure, and the upconversion luminescent material layer fills the gaps in the reflective layer and covers the reflective layer.
[0010] In one embodiment, at least one of the front side and the back side of the semiconductor substrate is formed into a pyramid texture structure.
[0011] In one embodiment, the reflective layer includes a face-centered cubic lattice structure or a simple cubic lattice structure.
[0012] In one embodiment, the particle size of the reflective layer is in the range of 200 to 450 nm.
[0013] In one embodiment, the material of the reflective layer includes at least one of silicon dioxide, titanium dioxide, polyethylene spheres or metal organic framework materials.
[0014] According to a second aspect of the present disclosure, a method for preparing a solar cell is provided, the method comprising:
[0015] Providing a semiconductor substrate, the semiconductor substrate comprising a front side and a back side arranged opposite to each other;
[0016] forming a first intrinsic amorphous silicon layer on the front surface of the semiconductor substrate, and forming a second intrinsic amorphous silicon layer on the back surface of the semiconductor substrate;
[0017] forming a first doped layer on the first intrinsic amorphous silicon layer, and forming a second doped layer on the second intrinsic amorphous silicon layer;
[0018] forming a first transparent conductive layer on the first doped layer, and forming a second transparent conductive layer on the second doped layer;
[0019] forming a composite film layer on the second transparent conductive layer, wherein the composite film layer comprises an up-conversion luminescent material layer and a reflective layer, wherein the reflective layer is a photonic crystal structure, and the up-conversion luminescent material layer fills the gaps in the reflective layer and covers the reflective layer;
[0020] A first metal electrode is formed on the first transparent conductive layer, and a second metal electrode is formed on the second transparent conductive layer.
[0021] In one embodiment, forming the composite film layer comprises:
[0022] forming a first mask layer on the first transparent conductive layer, and forming a second mask layer on the second transparent conductive layer;
[0023] patterning the second mask layer, retaining the second mask layer in the area where the second metal electrode is prepared, and removing the second mask layer in other areas;
[0024] A composite film layer is formed in the area where the second mask layer is removed.
[0025] In one embodiment, forming the reflective layer includes:
[0026] Preparing a precursor solution, wherein the precursor solution is a suspension having uniform solute size and uniform distribution, wherein the solute includes at least one of silicon dioxide, titanium dioxide, polyethylene spheres or metal organic framework materials;
[0027] The sample after patterning the second mask layer is vertically inserted into the precursor solution and then dried to form the reflective layer.
[0028] In one embodiment, forming the up-conversion luminescent material layer comprises:
[0029] Synthesize upconversion luminescent material nanoparticles by solvothermal method;
[0030] Dissolving the upconversion luminescent material nanoparticles in anhydrous ethanol to form a solution A;
[0031] After the reflection layer is formed, the up-conversion luminescent material layer is formed by spin coating solution A on the reflection layer.
[0032] In one embodiment, the reflective layer includes a face-centered cubic lattice structure or a simple cubic lattice structure.
[0033] In one embodiment, preparing the first metal electrode and the second metal electrode comprises:
[0034] After forming the composite film layer, removing the first mask layer and the remaining second mask layer;
[0035] A first metal electrode is formed on the first transparent conductive layer, and a second metal electrode is formed on the exposed second transparent conductive layer after removing the remaining second mask layer.
[0036] According to a third aspect of the present disclosure, a photovoltaic assembly is provided, comprising a solar cell as described in any one of the above embodiments.
[0037] A solar cell and a preparation method thereof, as well as a photovoltaic module disclosed herein, form a composite film layer consisting of a reflective layer and an up-conversion luminescent material layer on a second transparent conductive layer, wherein the up-conversion luminescent material layer captures and converts photons passing through the solar cell, converts long-wavelength incident light into visible light, and then the reflective layer mainly adopts a photonic crystal structure, which can not only guide the photons converted by the up-conversion luminescent material layer back into the interior of the solar cell, but also enhance the up-conversion luminescent intensity to improve the utilization rate of light, thereby improving the short-circuit current density of the solar cell, and at the same time can reduce the test error caused by the reflection of the copper platform of the IV tester.
[0038] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present disclosure, nor is it intended to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS
[0039] The above and other objects, features and advantages of the exemplary embodiments of the present disclosure will become readily understood by reading the detailed description below with reference to the accompanying drawings. In the accompanying drawings, several embodiments of the present disclosure are shown in an exemplary and non-limiting manner, in which:
[0040] In the drawings, the same or corresponding reference numerals represent the same or corresponding parts.
[0041] Figure 1 A schematic diagram of the structure of a solar cell provided in an embodiment of the present disclosure;
[0042] Figure 2a for Figure 1 One of the enlarged schematic diagrams of the box A in FIG.
[0043] Figure 2b for Figure 1 Another enlarged schematic diagram of the box A in FIG.
[0044] Figure 3 A flow chart of a method for preparing a solar cell provided in an embodiment of the present disclosure;
[0045] Figure 4a to Figure 4g A schematic diagram of the preparation process of a solar cell provided in an embodiment of the present disclosure.
[0046] Figure Number:
[0047] 10. Semiconductor substrate; 21. First intrinsic amorphous silicon layer; 22. Second intrinsic amorphous silicon layer; 31. First doped layer; 32. Second doped layer; 41. First transparent conductive layer; 42. Second transparent conductive layer; 51. First mask layer; 52. Second mask layer; 60. Composite film layer; 61. Reflective layer; 62. Up-conversion luminescent material layer; 71. First metal electrode; 72. Second metal electrode. DETAILED DESCRIPTION
[0048] In order to make the purpose, features, and advantages of the present disclosure more obvious and easy to understand, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present disclosure.
[0049] In the prior art, in order to improve the light utilization rate of heterojunction solar cells (reduce optical losses), the following aspects can be taken into consideration: 1. Double-sided microcrystal technology is adopted to enable both the front and back sides of the cell to efficiently absorb and convert light energy, thereby significantly increasing the overall light utilization; 2. The material of the light absorption layer is optimized, high-quality, low-defect and low-impurity materials are selected, and its thickness is precisely controlled to reduce carrier recombination while ensuring sufficient light absorption; 3. By improving the battery structure design, such as optimizing surface passivation, reducing optical losses, and enhancing the separation and transmission of carriers, the collection efficiency of photogenerated carriers can be improved; 4. Suitable packaging materials are explored to reduce light reflection and loss, so that more light can be effectively utilized by the battery; 5. The low-indium route of the target material can also be studied, which may have a positive impact on the light utilization rate while reducing costs; 6. Stacking heterojunction cells with perovskite cells is also an effective way to give full play to the advantages of both in different bands and further improve the comprehensive absorption and utilization efficiency of sunlight; 7. Special processes such as light injection treatment are used to activate related atoms and improve the conductivity of the film, thereby improving the photoelectric conversion efficiency of the battery.
[0050] The present disclosure provides a solar cell. Figure 1 A schematic diagram of the structure of a solar cell provided in an embodiment of the present disclosure, such as Figure 1 As shown, the solar cell comprises:
[0051] The semiconductor substrate 10 includes a front side and a back side which are opposite to each other.
[0052] The semiconductor substrate 10 may be a single semiconductor material substrate (e.g., a silicon substrate, a germanium substrate, etc.), a composite semiconductor material substrate (e.g., a germanium silicon substrate, etc.), or a silicon on insulator substrate (SOI), a germanium on insulator (GOI) substrate, or a polycrystalline silicon substrate, etc. In a preferred embodiment, the semiconductor substrate 10 may be crystalline silicon, and the crystalline silicon may be P-type single crystal silicon or N-type single crystal silicon. Preferably, it may be N-type single crystal silicon.
[0053] At least one of the front surface and the back surface of the semiconductor substrate 10 is formed into a pyramid texture structure.
[0054] The solar cell also includes: a first intrinsic amorphous silicon layer 21, a first doped layer 31, a first transparent conductive layer 41 and a first metal electrode 71 are sequentially prepared from the front side of the semiconductor substrate 10 upwards, and a second intrinsic amorphous silicon layer 22, a second doped layer 32, a second transparent conductive layer 42 and a second metal electrode 72 are sequentially prepared from the back side of the semiconductor substrate 10 downwards.
[0055] In one embodiment, the first intrinsic amorphous silicon layer 21 and the second intrinsic amorphous silicon layer 22 are passivation layers, which have a good passivation effect on the surface of the semiconductor substrate. Excellent surface passivation ability is an important condition for obtaining higher battery efficiency and can greatly improve the minority carrier life of the battery.
[0056] In one embodiment, the first doping layer 31 may be an N-type doping layer, and the second doping layer 32 may be a P-type doping layer.
[0057] The first doping layer 31 and the second doping layer 32 may be microcrystalline silicon doping layers or amorphous silicon doping layers.
[0058] The first doping layer 31 and the second doping layer 32 form a PN junction and a back field of a heterojunction solar cell.
[0059] In one embodiment, the first transparent conductive layer 41 and the second transparent conductive layer 42 are made of transparent conductive oxide, which can be a single layer or a stacked layer structure of materials such as indium tin oxide, aluminum-doped zinc oxide or tungsten-doped indium oxide. The transparent conductive layer can effectively increase the collection of carriers and reduce light reflection.
[0060] In one embodiment, the first metal electrode 71 and the second metal electrode 72 are used to form the positive and negative electrodes of the battery, effectively collecting photogenerated carriers, and their materials can be silver, silver-coated copper grid or copper. The first metal electrode 71 is arranged on the first transparent conductive layer 41, and the second metal electrode 72 is arranged on the second transparent conductive layer 42, so that the metal electrode and the transparent conductive layer are in direct contact, ensuring good ohmic contact.
[0061] Figure 2a for Figure 1 One of the enlarged schematic diagrams of the box A in FIG. Figure 2b for Figure 1 Another enlarged schematic diagram of box A in FIG.
[0062] like Figure 2a and Figure 2b As shown, the solar cell also includes: a composite film layer 60, which is located on the area of the second transparent conductive layer 42 that is not covered by the second metal electrode 72, and the composite film layer 60 includes an up-conversion luminescent material layer 62 and a reflective layer 61, wherein the reflective layer 61 is a photonic crystal structure, and the up-conversion luminescent material layer 62 fills the gaps in the reflective layer 61 and covers the reflective layer 61.
[0063] In one embodiment, the material of the reflective layer 61 includes at least one of silicon dioxide, titanium dioxide, polyethylene spheres, or metal organic framework materials.
[0064] This embodiment uses silicon dioxide to prepare a photonic crystal structure. The photonic crystal structure is mainly due to the large difference in refractive index between silicon dioxide and air, and there is a photonic bandgap. In the design of solar cells, by constructing a suitable photonic crystal structure on the surface of the second transparent conductive layer, the up-conversion luminescence intensity can be enhanced, and the reflection of light in a specific band can allow more light to be absorbed and utilized inside the cell, thereby improving the efficiency of the solar cell.
[0065] In one embodiment, the reflective layer 61 includes a face-centered cubic lattice structure or a simple cubic lattice structure (SC). Figure 2a As shown, the reflective layer 61 formed by the silicon dioxide material is a face-centered cubic lattice structure; in another embodiment, as shown in FIG. Figure 2b As shown, the reflective layer 61 formed by the metal organic framework material is a simple cubic lattice structure. In other embodiments, the reflective layer 61 can also be a body-centered cubic lattice structure.
[0066] In one embodiment, the particle size of the reflective layer 61 ranges from 200 nm to 450 nm.
[0067] The up-conversion luminescent material is usually composed of rare earth salt nanoparticles. The up-conversion luminescent material forms a composite film layer with the reflective layer under the action of a coating machine.
[0068] The present disclosure provides a method for preparing a solar cell. Figure 3 Flow chart of the method for preparing a solar cell provided in the embodiment of the present disclosure, see Figure 3 , the method comprises the following steps:
[0069] Step 301: providing a semiconductor substrate, wherein the semiconductor substrate comprises a front side and a back side that are oppositely arranged;
[0070] Step 302: forming a first intrinsic amorphous silicon layer on the front surface of the semiconductor substrate, and forming a second intrinsic amorphous silicon layer on the back surface of the semiconductor substrate;
[0071] Step 303: forming a first doped layer on the first intrinsic amorphous silicon layer, and forming a second doped layer on the second intrinsic amorphous silicon layer;
[0072] Step 304: forming a first transparent conductive layer on the first doped layer, and forming a second transparent conductive layer on the second doped layer;
[0073] Step 305: forming a composite film layer on the second transparent conductive layer, the composite film layer comprising an up-conversion luminescent material layer and a reflective layer, wherein the reflective layer is a photonic crystal structure, and the up-conversion luminescent material layer fills the gaps in the reflective layer and covers the reflective layer;
[0074] Step 306: Prepare a first metal electrode on the first transparent conductive layer, and prepare a second metal electrode on the second transparent conductive layer.
[0075] The method for preparing a solar cell provided by the embodiment of the present disclosure is further described in detail below in conjunction with specific embodiments. Figure 4a to Figure 4g A schematic diagram of the preparation process of a solar cell provided in an embodiment of the present disclosure.
[0076] First, see Figure 4a , perform step 301, provide a semiconductor substrate 10, and the semiconductor substrate 10 includes a front side and a back side that are arranged opposite to each other.
[0077] The semiconductor substrate 10 may be a single semiconductor material substrate (e.g., a silicon substrate, a germanium substrate, etc.), a composite semiconductor material substrate (e.g., a germanium silicon substrate, etc.), or a silicon on insulator substrate (SOI), a germanium on insulator (GOI) substrate, or a polycrystalline silicon substrate, etc. In a preferred embodiment, the semiconductor substrate 10 may be crystalline silicon, and the crystalline silicon may be P-type single crystal silicon or N-type single crystal silicon. Preferably, it may be N-type single crystal silicon.
[0078] Next, the method further includes: pre-cleaning the semiconductor substrate 10 and performing gettering on the semiconductor substrate 10 .
[0079] Next, see Figure 4b , the semiconductor substrate 10 is subjected to a texturing treatment. After the texturing step, at least one of the front and back sides of the semiconductor substrate 10 is formed into a pyramid texturing structure.
[0080] In actual operation, the texturing process includes: placing the semiconductor substrate 10 in a 0.5%-10% KOH solution, reacting at 50-85°C for 1min-20min. Under this condition, the velvet structure obtained is the best, which can reduce reflection and absorb more light sources. This embodiment mainly utilizes the anisotropic corrosion characteristics of silicon in low-concentration alkali solution. Silicon and alkali solution undergo a series of chemical reactions to form a pyramid velvet surface on the surface of the silicon wafer.
[0081] Next, see Figure 4c , perform step 302 to form a first intrinsic amorphous silicon layer 21 on the front surface of the semiconductor substrate 10 , and form a second intrinsic amorphous silicon layer 22 on the back surface of the semiconductor substrate 10 .
[0082] In actual operation, the first intrinsic amorphous silicon layer 21 and the second intrinsic amorphous silicon layer 22 may be deposited by a plasma enhanced chemical vapor deposition (PECVD) method.
[0083] In one embodiment, the first intrinsic amorphous silicon layer 21 and the second intrinsic amorphous silicon layer 22 are passivation layers, which have a good passivation effect on the surface of the semiconductor substrate. Excellent surface passivation ability is an important condition for obtaining higher battery efficiency and can greatly improve the minority carrier life of the battery.
[0084] Next, continue to see Figure 4c , perform step 303 to form a first doping layer 31 on the first intrinsic amorphous silicon layer 21 , and form a second doping layer 32 on the second intrinsic amorphous silicon layer 22 .
[0085] In actual operation, the first doping layer 31 and the second doping layer 32 may be deposited by a plasma enhanced chemical vapor deposition (PECVD) method.
[0086] In one embodiment, the first doping layer 31 may be an N-type doping layer, and the second doping layer 32 may be a P-type doping layer.
[0087] The first doping layer 31 and the second doping layer 32 may be microcrystalline silicon doping layers or amorphous silicon doping layers.
[0088] The first doping layer 31 and the second doping layer 32 form a PN junction and a back field of a heterojunction solar cell.
[0089] Next, continue to see Figure 4c , perform step 304 to form a first transparent conductive layer 41 on the first doping layer 31 , and form a second transparent conductive layer 42 on the second doping layer 32 .
[0090] In actual operation, the first transparent conductive layer 41 and the second transparent conductive layer 42 can be deposited by magnetron sputtering.
[0091] The first transparent conductive layer 41 and the second transparent conductive layer 42 are made of transparent conductive oxide, which may be a single layer or a stacked layer structure of materials such as indium tin oxide, aluminum-doped zinc oxide or tungsten-doped indium oxide. The transparent conductive layer can effectively increase the collection of carriers and reduce light reflection.
[0092] Next, see Figure 4d to Figure 4f ,as well as Figure 2a , execute step 305 to form a composite film layer 60 on the second transparent conductive layer 42, the composite film layer 60 includes an up-conversion luminescent material layer 62 and a reflective layer 61, wherein the reflective layer 61 is a photonic crystal structure, and the up-conversion luminescent material layer 62 fills the gaps in the reflective layer 61 and covers the reflective layer 61.
[0093] In one embodiment, forming the composite film layer 60 includes:
[0094] forming a first mask layer 51 on the first transparent conductive layer 41 and forming a second mask layer 52 on the second transparent conductive layer 42;
[0095] Patterning the second mask layer 52, retaining the second mask layer 52 in the area where the second metal electrode is prepared, and removing the second mask layer 52 in other areas;
[0096] A composite film layer 60 is formed in the region where the second mask layer 52 is removed.
[0097] For details, see Figure 4d , a first mask layer 51 is formed on the first transparent conductive layer 41 , and a second mask layer 52 is formed on the second transparent conductive layer 42 .
[0098] In actual operation, the first mask layer 51 and the second mask layer 52 can be formed by chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD) or other deposition methods.
[0099] Next, see Figure 4e , patterning the second mask layer 52, retaining the second mask layer 52 in the area where the second metal electrode is prepared, and removing the second mask layer 52 in other areas.
[0100] The second mask layer 52 for preparing the area where the second metal electrode is located is retained here so that the second metal electrode can be formed on the second transparent conductive layer 42 later.
[0101] In actual operation, the hard mask plate can be covered on the upper surface of the second mask layer, the first mask layer and the second mask layer covered by the hard mask plate are cured under 365nm ultraviolet light, and then the above sample is immersed in a sodium carbonate solution with a mass fraction of 1%-3% for development to obtain a patterned second mask layer.
[0102] Next, see Figure 4f , a composite film layer 60 is formed in the area where the second mask layer 52 is removed.
[0103] Specifically, Figure 2a As shown, forming the composite film layer 60 includes: first forming a reflective layer 61 , and then forming an up-conversion luminescent material layer 62 .
[0104] Forming the reflective layer 61 includes: preparing a precursor solution, the precursor solution is a suspension with uniform solute size and uniform distribution, and the solute includes at least one of silicon dioxide (SiO2), titanium dioxide (TiO2), polyethylene balls (PS) or metal organic framework materials (MOFs); vertically inserting the sample after the patterned second mask layer 52 into the precursor solution, and then drying to form the reflective layer 61.
[0105] In one embodiment, the reflective layer 61 includes a face-centered cubic lattice structure (FCC) or a simple cubic lattice structure (SC).
[0106] In a specific embodiment, if Figure 2a As shown, a silica suspension is used as a precursor solution for photonic crystals, wherein the solute particles of the precursor solution must be uniform in size to ensure the formation of an orderly periodic arrangement structure; the solvent is a mixture of one or more common solvents such as ethanol, isopropanol or water; the silica particle size is about 200-450nm, and the silica is evenly dispersed in the solvent by ultrasound; then the sample after the patterned second mask layer 52 is vertically inserted into the suspension in which the silica is evenly dispersed, fixed and moved to a constant temperature oven for drying, and allowed to self-assemble, the temperature is usually 50-60°C; as the solvent evaporates, the silica forms a dense stack with the surface of the second transparent conductive layer 42 as the substrate under the combined action of its own gravity, buoyancy, van der Waals force and electrostatic force, thereby forming a photonic crystal film with a face-centered cubic structure (FCC).
[0107] This embodiment uses silicon dioxide to prepare a photonic crystal structure. The photonic crystal structure is mainly due to the large difference in refractive index between silicon dioxide and air, and there is a photonic bandgap. In the design of solar cells, by constructing a suitable photonic crystal structure on the surface of the second transparent conductive layer, the up-conversion luminescence intensity can be enhanced, and the reflection of light in a specific band can allow more light to be absorbed and utilized inside the cell, thereby improving the efficiency of the solar cell.
[0108] In another specific embodiment, Figure 2b As shown, a certain amount of zinc acetate is weighed and dissolved in deionized water, named solution B; a certain amount of 2-methylimidazole is added to a certain amount of deionized water, and a surfactant, such as hexadecyltrimethylammonium bromide (CTAB for short), is added, named solution C; then solution C is added to solution B at a certain speed through a micro-injection pump, named mixed solution D; after the reaction is completed, the mixed solution D is centrifuged and washed to obtain metal organic framework material ZIF-8 nanoparticles of a certain shape; then the sample after the patterned second mask layer 52 is vertically inserted into the suspension in which the metal organic framework material ZIF-8 nanoparticles are uniformly dispersed, fixed and moved to a constant temperature oven for drying, and allowed to self-assemble, the temperature is usually 50-60°C; as the solvent evaporates, the metal organic framework material ZIF-8 nanoparticles form a dense stack with the surface of the second transparent conductive layer 42 as the substrate under the combined action of their own gravity, buoyancy, van der Waals force and electrostatic force, and then form a photonic crystal film with a simple cubic lattice structure (SC).
[0109] The photonic crystal structure is a microstructure formed by the periodic arrangement of materials with different refractive indices in space. The refractive indices of these materials are quite different, forming obvious differences in optical properties. Due to its special structure, a photonic band gap appears. When the wavelength of the incident light is coupled with the position of the photonic band gap, the incident light will be bounded by the photonic band gap on the surface of the photonic crystal, resulting in a continuous increase in the density of photon states, which will enhance the electromagnetic field on the surface of the photonic crystal, increase the probability of energy level transitions inside the upconversion luminescent material, and significantly improve the upconversion luminescence intensity; in addition, due to the existence of the photonic band gap, photons within a specific wavelength range cannot propagate in the photonic crystal and are thus reflected back.
[0110] In other embodiments, the reflective layer 61 may also be a body-centered cubic lattice structure.
[0111] In one embodiment, the particle size of the reflective layer 61 ranges from 200 nm to 450 nm.
[0112] Next, an upconversion luminescent material layer 62 is formed, including: synthesizing upconversion luminescent material nanoparticles by a solvothermal method; dissolving the upconversion luminescent material nanoparticles in anhydrous ethanol to form a solution A; after forming the reflective layer 61, spin coating the solution A on the reflective layer 61 to form the upconversion luminescent material layer 62.
[0113] Upconversion luminescence, also known as anti-Stokes luminescence, refers to a material that can emit high-energy light after being excited by low-energy light. That is, after being excited by long-wavelength, low-frequency light, it emits short-wavelength, high-frequency light. The material used is usually called upconversion luminescent material.
[0114] The up-conversion luminescent material is usually composed of rare earth salt nanoparticles. The up-conversion luminescent material forms a composite film layer with the reflective layer under the action of a coating machine.
[0115] In a specific embodiment, fluorine-doped rare earth metal nanocrystals are synthesized by a solvent thermal method, a co-precipitation method, a high-temperature solid phase method or a sol-gel method. In this embodiment, a solvent thermal method is used to synthesize upconversion luminescent material nanoparticles; then a certain amount of upconversion luminescent material nanoparticles are measured and dissolved in an appropriate amount of anhydrous ethanol, and after sufficient stirring, a solution A is formed; then a layer of the above-configured solution A is spin-coated on the reflective layer 61 using a coating machine, and finally an upconversion luminescent material layer 62 of a certain thickness is obtained, and the upconversion luminescent material layer 62 fills the gaps in the reflective layer 61 and covers the reflective layer 61.
[0116] Next, see Figure 4g , perform step 306 to prepare a first metal electrode 71 on the first transparent conductive layer 41 , and prepare a second metal electrode 72 on the second transparent conductive layer 42 .
[0117] In one embodiment, preparing the first metal electrode 71 and the second metal electrode 72 includes:
[0118] After forming the composite film layer 60, the first mask layer 51 and the remaining second mask layer 52 are removed;
[0119] A first metal electrode 71 is formed on the first transparent conductive layer 41 , and a second metal electrode 72 is formed on the exposed second transparent conductive layer 42 after the remaining second mask layer 52 is removed.
[0120] In actual operation, the sample may be immersed in an alkaline solution of a certain concentration to remove the first mask layer 51 and the remaining second mask layer 52 . The alkaline solution of a certain concentration may be, for example, a 3% sodium hydroxide solution.
[0121] In actual operation, the process of forming the first metal electrode 71 and the second metal electrode 72 includes but is not limited to a screen printing process.
[0122] The first metal electrode 71 and the second metal electrode 72 are used to form the positive and negative electrodes of the battery, effectively collecting photogenerated carriers, and the materials thereof can be silver, silver-coated copper grid or copper. The first metal electrode 71 is disposed on the first transparent conductive layer 41, and the second metal electrode 72 is disposed on the second transparent conductive layer 42, so that the metal electrode and the transparent conductive layer are in direct contact, ensuring good ohmic contact.
[0123] The embodiments of the present disclosure also provide a photovoltaic assembly, comprising a solar cell as described in any of the above embodiments.
[0124] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps recorded in this disclosure can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solutions disclosed in this disclosure can be achieved, and this document does not limit this.
[0125] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present disclosure, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.
[0126] The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.
Claims
1. A solar cell, characterized in that: The solar cell comprises: A semiconductor substrate, the semiconductor substrate comprising a front side and a back side arranged opposite to each other; The semiconductor substrate is provided with a first intrinsic amorphous silicon layer, a first doped layer, a first transparent conductive layer and a first metal electrode in sequence from the front side upward, and a second intrinsic amorphous silicon layer, a second doped layer, a second transparent conductive layer and a second metal electrode in sequence from the back side downward; A composite film layer, wherein the composite film layer is located on an area of the second transparent conductive layer that is not covered by the second metal electrode, and the composite film layer comprises an upconversion luminescent material layer and a reflective layer, wherein the reflective layer is a photonic crystal structure, and the upconversion luminescent material layer fills the gaps in the reflective layer and covers the reflective layer.
2. The solar cell according to claim 1, characterized in that: At least one of the front side and the back side of the semiconductor substrate is formed into a pyramid texture structure.
3. The solar cell according to claim 1, characterized in that The reflective layer includes a face-centered cubic lattice structure or a simple cubic lattice structure.
4. The solar cell according to claim 3, characterized in that: The particle size of the reflective layer ranges from 200 to 450 nm.
5. The solar cell according to claim 1, characterized in that: The material of the reflective layer includes at least one of silicon dioxide, titanium dioxide, polyethylene spheres or metal organic framework materials.
6. A method for preparing a solar cell, characterized in that: The method comprises: Providing a semiconductor substrate, the semiconductor substrate comprising a front side and a back side arranged opposite to each other; forming a first intrinsic amorphous silicon layer on the front surface of the semiconductor substrate, and forming a second intrinsic amorphous silicon layer on the back surface of the semiconductor substrate; forming a first doped layer on the first intrinsic amorphous silicon layer, and forming a second doped layer on the second intrinsic amorphous silicon layer; forming a first transparent conductive layer on the first doped layer, and forming a second transparent conductive layer on the second doped layer; forming a composite film layer on the second transparent conductive layer, wherein the composite film layer comprises an up-conversion luminescent material layer and a reflective layer, wherein the reflective layer is a photonic crystal structure, and the up-conversion luminescent material layer fills the gaps in the reflective layer and covers the reflective layer; A first metal electrode is formed on the first transparent conductive layer, and a second metal electrode is formed on the second transparent conductive layer.
7. The method according to claim 6, characterized in that Forming the composite film layer comprises: forming a first mask layer on the first transparent conductive layer, and forming a second mask layer on the second transparent conductive layer; patterning the second mask layer, retaining the second mask layer in the area where the second metal electrode is prepared, and removing the second mask layer in other areas; A composite film layer is formed in the area where the second mask layer is removed.
8. The method according to claim 7, characterized in that Forming the reflective layer comprises: Preparing a precursor solution, wherein the precursor solution is a suspension having uniform solute size and uniform distribution, wherein the solute includes at least one of silicon dioxide, titanium dioxide, polyethylene spheres or metal organic framework materials; The sample after patterning the second mask layer is vertically inserted into the precursor solution and then dried to form the reflective layer.
9. The method according to claim 8, characterized in that Forming the up-conversion luminescent material layer comprises: Synthesize upconversion luminescent material nanoparticles by solvothermal method; Dissolving the upconversion luminescent material nanoparticles in anhydrous ethanol to form a solution A; After the reflection layer is formed, the up-conversion luminescent material layer is formed by spin coating solution A on the reflection layer.
10. The method according to claim 6, characterized in that The reflective layer includes a face-centered cubic lattice structure or a simple cubic lattice structure.
11. The method according to claim 7, characterized in that The first metal electrode and the second metal electrode are prepared, comprising: After forming the composite film layer, removing the first mask layer and the remaining second mask layer; A first metal electrode is formed on the first transparent conductive layer, and a second metal electrode is formed on the exposed second transparent conductive layer after removing the remaining second mask layer.
12. A photovoltaic module, characterized in that: The invention comprises the solar cell according to any one of claims 1 to 5.