A silicon / perovskite three-terminal tandem solar cell structure and method of fabrication

Abstract

The application discloses a silicon / perovskite three-terminal stacked solar cell structure and a preparation method thereof. The silicon / perovskite three-terminal stacked solar cell comprises a perovskite top solar cell unit and a back contact silicon solar cell unit. The structure of the perovskite top solar cell unit is sequentially arranged from top to bottom as a first metal electrode layer, a first reflection reduction layer, a first transparent conductive oxide layer, a first transparent oxide buffer layer, a first transport layer, a first passivation layer, a perovskite absorber layer and a second transport layer. The silicon bottom cell and the perovskite top cell of the silicon / perovskite three-terminal stacked solar cell are in a three-terminal stacked cell structure, and do not need to meet the current matching requirement of a two-terminal stacked cell, so that a higher photoelectric conversion efficiency than that of a sub-cell can be obtained, and the preparation process is simple and the preparation cost is low.

Description

Technical Field

[0001] This invention relates to the field of solar cell structure design and manufacturing technology, and particularly to the structure and manufacturing method of silicon / perovskite tandem solar cells. Background Technology

[0002] Perovskite solar cells have become a research hotspot in the photovoltaic field in recent years. In just 10 years, their efficiency has increased from less than 3% to 25.5%, making them the fastest-growing type of solar cell in terms of efficiency. Perovskite materials and devices not only possess advantages in physical properties such as good overall performance, high extinction coefficient, suitable band gap width, and high open-circuit voltage, but also have simple structures, mild preparation conditions, and convenient fabrication processes, thus attracting widespread attention.

[0003] Limited by the SQ (Solid Quotient) theoretical efficiency limit, significantly improving the efficiency of single-junction silicon or perovskite solar cells is already difficult. However, combining the two to form a tandem solar cell holds the promise of breaking through the SQ limit of single-junction cells. Silicon primarily converts the infrared / near-infrared portion of sunlight into electrical energy, while perovskite compounds mainly utilize the visible light portion of the spectrum. Therefore, tandem solar cells made of silicon and perovskite can achieve higher efficiency than single cells alone.

[0004] Current research reports on perovskite / silicon tandem solar cells generally employ a two-terminal structure with the top and bottom cells connected in series, or a four-terminal structure with the top and bottom cells being independent of each other. Figure 1 and Figure 2 As shown. Based on the relationship between the theoretical limiting efficiency of the battery and the band gap of the top cell's light-absorbing layer, the optimal band gap of the top cell's light-absorbing layer for two-terminal batteries is 1.73 eV, while the optimal band gap for the top cell's light-absorbing layer for three-terminal and four-terminal batteries is 1.8 eV.

[0005] like Figure 1 The diagram shows a schematic of a silicon / perovskite tandem solar cell structure with two ends. From top to bottom, the two ends of the cell include a metal electrode A, a transparent conductive layer B, a perovskite absorber layer C, a tunneling layer D, a silicon cell E, and a back electrode F. The theoretical limiting efficiency of the two-end cell varies significantly with the bandgap of the top cell; therefore, doping is required to control the bandgap of the perovskite material to approximately 1.6-1.8 eV. Furthermore, the transparent conductive layer, emitter, and back field layer in the two-end cell structure exhibit parasitic absorption, which affects the device efficiency. Since the top and bottom cells are connected in series, a reasonable spectral distribution is needed to match the currents of the top and bottom cells and achieve the maximum output current. This means that the two sub-cells will mutually limit each other, with the final output current based on the sub-cell with the smaller current. Therefore, there are certain limitations on the selection and thickness of the perovskite material.

[0006] like Figure 2The diagram shows a schematic of a four-terminal silicon / perovskite tandem solar cell. The four-terminal structure comprises two mechanically stacked sub-cells. These two sub-cells are independently placed and connected, each maintaining its maximum power point independently. The top and bottom cells are connected via a high-efficiency tunnel junction, allowing more photons to reach the bottom cell. The top cell, from top to bottom, mainly consists of a transparent conductive layer B, a perovskite absorption layer C, and a transparent conductive layer G. The bottom cell, from top to bottom, mainly consists of a metal electrode H, a transparent conductive layer K, a silicon cell E, and a back electrode F. The two sub-cells of the four-terminal cell do not affect each other during preparation and do not require current matching. However, the use of transparent conductive layers as electrode materials on both sides of the top cell and the light-receiving surface of the bottom cell is detrimental to reducing cell cost. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a structure and a method for preparing a three-terminal tandem solar cell, which is prepared by using a back-contact crystalline silicon solar cell as the bottom cell and combining it with a wide-bandgap perovskite top cell.

[0008] This three-terminal stacked cell combines the advantages of two-terminal and four-terminal stacked cells. It has a simple structure and its device efficiency is not sensitive to changes in the bandgap of the top cell's light-absorbing layer. It is a stacked cell solution with great potential for high efficiency.

[0009] This invention is achieved by providing a silicon / perovskite three-terminal tandem solar cell structure and its fabrication method, the structure of which mainly includes a perovskite top solar cell unit and a silicon solar cell unit.

[0010] Furthermore, the band gap of the perovskite absorber layer in the perovskite solar cell is controlled at around 1.6-1.8 eV.

[0011] Furthermore, the structure of the perovskite top-layer solar cell unit is arranged from top to bottom as follows: a first metal electrode layer, a first anti-reflection layer, a first transparent conductive layer, a first buffer layer, a first transport layer, a first passivation layer, a perovskite absorption layer, and a second transport layer.

[0012] Furthermore, the silicon cell is a back-contact silicon solar cell structure.

[0013] Furthermore, the silicon heterojunction solar cell structure, from top to bottom, includes a crystalline silicon layer, a second passivation layer, a third transport layer, a fourth transport layer, a second metal electrode layer, and a third metal electrode layer.

[0014] The structure of the silicon / perovskite three-terminal tandem solar cell of the present invention enables efficient electron or hole transport in the top cell portion, while simultaneously enabling electron and hole transport in the silicon cell unit, thereby realizing the structure of the three-terminal tandem solar cell.

[0015] The advantage of this invention is that it can achieve effective absorption of different wavelengths based on the absorption properties of different absorption layers, thereby obtaining better battery efficiency than two sub-cells.

[0016] This invention does not require strict control of the material's band gap to meet the current matching problem of the two sub-cells, and the photocurrents of the two sub-cells are independent.

[0017] The preparation structure and conditions of this invention are relatively simple, which can effectively reduce the cost of battery manufacturing. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the structure of the present invention.

[0019] Figure 1 This is a schematic diagram of a common silicon / perovskite two-terminal tandem solar cell.

[0020] Figure 2 This is a schematic diagram of a common silicon / perovskite four-terminal tandem solar cell.

[0021] Figure 3 This is a schematic diagram of the structure of the silicon / perovskite three-terminal stacked solar cell of the present invention;

[0022] Figure 4 This is a schematic diagram of another structure of the silicon / perovskite three-terminal stacked solar cell of the present invention;

[0023] Figure 5 This is a schematic diagram of the transport layer structure of a back-contact silicon solar cell. Detailed Implementation

[0024] To make the objectives, technical problems, and advantages of the embodiments of the present invention clearer, a more clear and complete description is provided below with reference to the accompanying drawings and technical solutions of the embodiments of the present invention. It should be noted that the specific examples described herein are only some embodiments of the present invention, and not all embodiments.

[0025] As attached Figure 1-5 As shown, the present invention provides a silicon / perovskite three-terminal tandem solar cell, which mainly includes a perovskite top solar cell unit as the top cell and a silicon solar cell unit as the bottom cell.

[0026] The solar cell comprises, from bottom to top, a bottom cell and a top cell. The top cell is a perovskite solar cell unit, which comprises, from top to bottom, a first metal electrode layer (1), a first anti-reflection layer (2), a first transparent conductive layer (3), a first buffer layer (4), a first transport layer (5), a first passivation layer (6), a perovskite absorption layer (7), and a second transport layer (8).

[0027] The bottom cell is a silicon-based solar cell unit. The bottom cell adopts a back contact structure. The structure of the silicon-based solar cell unit with the back contact structure from top to bottom is as follows: a second passivation layer (10), a silicon substrate (9), a second passivation layer (10), a third transport layer (11) and a fourth transport layer (12), a second metal electrode layer (13), and a third metal electrode layer (14). The third transport layer (11) and the fourth transport layer (12) are the electron and hole transport layers of the silicon-based solar cell, respectively, and are both located on the back side of the silicon-based solar cell. A second metal electrode layer (13) is disposed on the third transport layer (11), and a third metal electrode layer (14) is disposed on the fourth transport layer (12). The second metal electrode layer (13) and the third metal electrode layer (11) are also located on the back side of the silicon-based solar cell.

[0028] The first metal electrode layer, the second metal electrode layer, and the third metal electrode layer constitute a three-terminal output structure.

[0029] Wherein, the first transport layer (5) and the second transport layer (8) are respectively the electron transport layer and the hole transport layer of the perovskite top solar cell, or respectively the hole transport layer and the electron transport layer; wherein, the electron transport layer material is any one of titanium dioxide (TiO2), tin dioxide (SnO2), zinc oxide (ZnO) and carbon 60 (C60); the hole transport layer material is cuprous iodide (CuI) or nickel oxide (NiO). x One of copper thiocyanate (CuSCN).

[0030] The silicon substrate is either an n-type or p-type crystalline silicon substrate, and can be any one of the following structures: double-sided polished, single-sided polished, single-sided texturing, or double-sided texturing.

[0031] The second passivation layer (10) is required to passivate defects on the surface of the crystalline silicon substrate. The passivation layer material is any one of amorphous silicon, silicon oxide, and aluminum oxide.

[0032] The third transport layer (11) and the fourth transport layer (12) are the electron transport layer and hole transport layer of the crystalline silicon bottom cell, respectively. The electron transport layer material is any one of n-type silicon, titanium dioxide (TiO2), zinc oxide (ZnO), and tin dioxide (SnO2); the hole transport layer material is p-type silicon, molybdenum trioxide (MoO3), tungsten trioxide (WO3), and vanadium oxide (VO3). x Any one of the following. Electrode material:

[0033] The electrode of the present invention mainly comprises two parts: a first metal electrode layer (1) on the front side of the perovskite top cell, a second metal electrode layer (13) on the back side of the silicon bottom cell, and a third metal electrode layer (14).

[0034] The first electrode material of the top electrode is generally in the form of conductive grid lines. The back electrode generally uses a square template or a template of conductive grid lines. The electrode material can be any metal such as gold, silver, aluminum, copper, tin, magnesium, or aluminum, or a composite electrode material composed of any different metals.

[0035] The top electrode and back electrode can be prepared by thermal evaporation or screen printing, but are not limited to these two methods.

[0036] The thickness of the electrode is controlled differently depending on the preparation method, generally ranging from 200nm to 500nm. For example, for thermal evaporation, the amount of metal to be evaporated, the sample height, and the evaporation current and voltage need to be controlled to adjust the evaporation thickness. In contrast, the thickness in screen printing requires control of the printing amount, sample height, and pressure.

[0037] Anti-reflection layer (2):

[0038] In multilayer devices, reflection loss accounts for a large portion of optical loss, while antireflection layers can reduce light reflection and increase light absorption by increasing the light transmittance of the device. Therefore, the design of antireflection layers is extremely important in battery structures. The reflectivity of antireflection layer materials needs to be between that of perovskite and air. Commonly used materials include fluoride materials such as LiF and MgF2, transparent conductive oxides (TCO), silicon nitride, or polydimethylsiloxane (PDMS). Common preparation methods include sol-gel method, chemical vapor deposition, sputtering, and electron beam evaporation. Any method in the art for preparing antireflection materials can be used, but it is not limited to the preparation methods mentioned above.

[0039] Transparent conductive layer (3):

[0040] For thin-film solar cells, the middle semiconductor layer has almost no lateral conductivity. Therefore, a transparent conductive film must be used to effectively collect the cell's current. Simultaneously, the transparent conductive film possesses high transmittance and anti-reflection properties, allowing most of the light to enter the absorption layer. The materials are mainly transparent conductive oxide films, such as any one of indium tin oxide (ITO), indium zinc oxide (IZO), aluminum-doped zinc oxide (AZO), tungsten-doped indium oxide (IWO), or zirconium-doped indium oxide (IZrO), with a thickness ranging from 100nm to 300nm.

[0041] The transparent oxide conductive layer of the present invention can be prepared by commonly used methods in the art, such as magnetron sputtering, chemical vapor deposition, and electron beam evaporation, including but not limited to the above-mentioned preparation methods.

[0042] Buffer layer (4):

[0043] The buffer layer mainly serves to protect the transport layer structure during the preparation of the transparent conductive layer, but it must not have a negative impact on the overall battery performance. Therefore, this buffer layer needs to have a certain level of conductivity and good transmittance, and the preparation conditions must be relatively mild.

[0044] The buffer layer used in this invention can be a transparent conductive oxide, such as any one of molybdenum oxide, tin oxide, vanadium oxide, or tungsten oxide. The conductivity and transmittance of the oxide are related to its thickness; the preferred thickness in this invention is 20 nm-60 nm. The molybdenum oxide prepared in this invention can be prepared using any of the methods for preparing transparent oxides in this field, such as thermal evaporation, thermal reactive evaporation, or electron beam evaporation, but is not limited to the methods mentioned above.

[0045] Perovskite solar cell:

[0046] Perovskite solar cells mainly consist of an electron transport layer, a perovskite absorber layer, and a hole transport layer.

[0047] Furthermore, in order to optimize the performance of perovskite solar cells, a passivation layer can be added to mitigate the interface defects between the perovskite absorber layer and the transport layer.

[0048] Furthermore, perovskite solar cells can be classified into two types based on their structure: pin-type and nip-type.

[0049] Furthermore, the two different structures will be described in detail in the implementation examples that follow.

[0050] The perovskite absorber layer (7) has an ABX3 structure.

[0051] A is an organic or inorganic monovalent cation, including but not limited to methylammonium cations (CH3NH3). + ), formamidinium cation (NH2CHNH2) + ), cesium cation (Cs) + ), rubidium cations (Rb + Or a combination of the above ions in a certain proportion; B is any one of the divalent metal cations of transition metals and elements from group I3 to I5, such as lead cation (Pb). 2+ ), tin cation (Sn) 2 + ), germanium cation (Ge 2+ ), copper cations (Cu) 2+ ) or combinations thereof;

[0052] X includes, but is not limited to, chloride ions (Cl...). - ), bromide ions (Br) - ), iodide ions (I) -Halogen anions such as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 ...

[0053] This invention prioritizes the use of wide bandgap perovskite materials, aiming to control the bandgap to within the required range of 1.6-1.8 eV. Therefore, the selection of perovskite materials includes, but is not limited to, Cs. x FA y MA 1-x-y PbI z Br 3-z , where 0≤x≤0.2, 0.5≤y≤0.9, 2≤z≤3, and 0.5≤x+y≤1.

[0054] The perovskite absorber layer can be prepared by any method available in the art, including but not limited to spin coating, evaporation, one-step method, two-step method, anti-solvent method, etc.

[0055] By optimizing the thickness of the perovskite material, the optimal thickness of this invention is controlled between 400nm and 1000nm.

[0056] Electron transport layer materials are materials that can accept and transport negatively charged electrons. Semiconductor materials with high electron affinity and ionic potential energy are usually used as electron transport layer materials.

[0057] Furthermore, energy level matching must be achieved between the electron transport layer and the perovskite layer to form an electron-selective contact.

[0058] The electron transport layer material can be any of the n-type oxides or n-type organic materials commonly used in the field of perovskite batteries, or a combination thereof. The n-type oxides include, but are not limited to, materials such as titanium dioxide (TiO2), tin dioxide (SnO2), and zinc oxide (ZnO). The n-type organic materials include, but are not limited to, fullerene derivatives ([6,6]-phenyl-C61-butyric acid methyl ester, PC61BM) and carbon 60 (C60). The thickness is controlled between 20nm and 100nm. The preparation method can be any of the following: spin coating, thermal evaporation, atomic layer deposition, reactive plasma deposition, sputtering, etc.

[0059] The function of the hole transport layer is to extract holes from the perovskite and transfer them to the electrodes.

[0060] Furthermore, the hole transport layer material used in this invention should satisfy valence band matching and have ideal hole mobility, and also have the ability to block electrons.

[0061] The hole transport layer is generally composed of p-type semiconductor materials commonly used in perovskite solar cells. Common hole transport materials mainly fall into three categories: organic polymers, small organic molecules, and inorganic compounds. Organic polymers can be at least one of poly(3,4-ethylenedioxythiophene:polystyrene sulfonate (PEDOT:PSS), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), and poly(3-hexylthiophene-2,5-diyl) (P3HT). Small organic molecules can be at least one of 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (spiro-MeOTAD) and tetrathiafulvalene (tetrathiafulvalene). Inorganic compounds include, but are not limited to, copper oxide (CuO), cuprous iodide (CuI), nickel oxide (NiOx), and copper thiocyanate (CuSCN), or combinations thereof, with a thickness controlled between 100 nm and 300 nm. The preparation method can be any one of spin coating, thermal reactive evaporation, atomic layer deposition, reactive plasma deposition, magnetron sputtering, etc.

[0062] Silicon-based solar cell:

[0063] Silicon-based solar cells mainly include any one of heterojunction cells, back contact cells, PERC back passivated cells, or Top-con cells. This invention selects a back contact silicon solar cell as the base cell.

[0064] The silicon-based battery of the present invention comprises, from top to bottom, a second passivation layer, a crystalline silicon layer, a second passivation layer, a third transport layer, a fourth transport layer, a second metal electrode layer, and a third metal electrode layer.

[0065] The crystalline silicon layer can be an n-type or p-type crystalline silicon wafer. The silicon substrate can be any of the following structures: double-sided polished, single-sided polished, single-sided texturized, or double-sided texturized.

[0066] The passivation layer passivates defects on the surface of the crystalline silicon substrate. The passivation material can be any of the following materials: amorphous silicon, silicon oxide, aluminum oxide, etc., and the thickness is 5nm-15nm.

[0067] The transport layer material can be either an n-type or p-type semiconductor material. The preparation method of the transport layer material can be any one of thermal reactive evaporation, atomic layer deposition, plasma-enhanced chemical vapor deposition, magnetron sputtering, etc.

[0068] like Figure 5 As shown, a complementary template is used between the two transport layers, and a metal electrode with the same shape as the above-mentioned transport layer can be prepared by any method in the art, such as evaporation or screen printing.

[0069] The silicon / perovskite three-terminal tandem solar cell structure of the present invention will be further explained below with specific examples:

[0070] Example 1

[0071] As shown in the figure, this invention provides a method for fabricating a silicon / perovskite three-terminal tandem solar cell.

[0072] Step 1: Select a suitable n-type double-sided polished silicon wafer for cleaning.

[0073] Step 2: Passivate the silicon wafer by depositing aluminum oxide on the upper and lower surfaces using atomic layer deposition (ALD) with a thickness of 1 nm to 5 nm.

[0074] Step 3: Using a template for shielding, prepare a tin dioxide electron transport layer on the lower surface via thermal reactive evaporation, with a thickness of 20nm-80nm. Then, evaporate magnesium and aluminum electrodes of the same shape using thermal evaporation, with thicknesses of 100nm-200nm and 300nm-500nm, respectively.

[0075] Step 4: Using the complementary template of the above template, a molybdenum oxide hole transport layer with a thickness of 10-20 nm is prepared by thermal reactive evaporation. Based on this, magnesium and aluminum electrodes of the same shape are evaporated using thermal evaporation, with thicknesses of 10 nm-30 nm and 300 nm-500 nm, respectively. Step 5: A 10 nm-30 nm thick tin dioxide film is deposited on the passivated silicon substrate at 150 degrees Celsius using atomic layer deposition (ALD) to complete the fabrication of the electron transport layer.

[0076] Step 6: Dissolve lead iodide, methylamine iodide, cesium bromide, and formamidinium iodide in a DMSO / DMF solution in a certain proportion. After thorough stirring and dissolution, filter to obtain the perovskite precursor solution. Spin-coat at 5000 rpm for 8 seconds, then add the antisolvent chlorobenzene dropwise. Continue spin-coating for 30 seconds, then heat on a 100°C heating stage for 10 minutes to complete the preparation of the perovskite absorber layer (500nm-1000nm).

[0077] Step 7: Dissolve polymethyl methacrylate (PMMA) in chlorobenzene (CB) solution at a ratio of 5 mg / ml to obtain passivation layer solution. Spin coat at 5000 rpm for 30 seconds, then heat on a heating stage at 100 degrees Celsius for 10 minutes to complete the preparation of passivation layer between perovskite and hole transport layer with a thickness of 50 nm-100 nm.

[0078] Step 8: A hole transport layer solution is prepared by doping spiro-MeOTAD with a certain ratio of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), 4-tert-butylpyridine (TBP) and cobalt(III) complex. The solution is then spin-coated at 4000 rpm for 30 seconds to prepare a hole transport layer with a thickness of 100 nm-200 nm.

[0079] Step 9: Using a thermal reaction evaporation method, deposit a layer of molybdenum oxide as a buffer layer on the surface of the hole transport layer, with a thickness of 20nm-40nm.

[0080] Step 10: Prepare an aluminum-doped zinc oxide layer with a thickness of 150 nm-250 nm on the molybdenum oxide buffer layer using magnetron sputtering. Step 11: Use electron beam evaporation to deposit 10-30 nm of MgF2 as an antireflection layer.

[0081] Step 12: Prepare silver gate lines on the antireflection layer using a conductive gate line template by thermal evaporation, with a thickness of 150nm-300nm.

[0082] Example 2

[0083] As shown in the figure, this invention provides another method for fabricating a silicon / perovskite three-terminal tandem solar cell.

[0084] Step 1: Select a suitable p-type double-sided polished silicon wafer for cleaning.

[0085] Step 2: Use plasma deposition to deposit amorphous silicon on the upper and lower surfaces of the silicon wafer to prepare a passivation layer with a thickness of 5-15 nm.

[0086] Step 3: Using a template for shielding, prepare a tin dioxide electron transport layer on the lower surface via thermal reactive evaporation, with a thickness of 10nm-30nm. Then, evaporate magnesium and aluminum electrodes of the same shape using thermal evaporation, with thicknesses of 10nm-30nm and 200nm-300nm respectively.

[0087] Step 4: Using the complementary template of the above template, prepare a molybdenum oxide hole transport layer with a thickness of 10-20 nm by thermal reaction evaporation in the same way. Based on this, evaporate magnesium and aluminum electrodes of the same shape by thermal evaporation, with thicknesses of 10 nm-30 nm and 200 nm-300 nm, respectively.

[0088] Step 5: Weigh a certain amount of PTAA and dissolve it in the CB solution in a certain proportion. After stirring thoroughly, a hole transport layer solution is obtained. Spin coat the silicon wafer surface at a speed of 4000 rpm. After maintaining the rotation for 30 seconds, heat it on a heating stage at 140 degrees Celsius for 3 minutes to obtain the hole transport layer.

[0089] Step 6: Dissolve lead iodide, methylamine iodide, cesium bromide, and formamidinium iodide in a certain ratio in a solution of dimethyl sulfoxide (DMSO) / N,N-dimethylformamide (DMF). After thorough stirring and dissolution, filter to obtain the perovskite precursor solution. Spin-coat at 5000 rpm for 20 seconds, then add the antisolvent CB dropwise. Continue spin-coating for 30 seconds, then heat on a 100°C heating stage for 50 minutes to complete the preparation of the perovskite absorber layer. The preferred thickness is 500 nm-900 nm.

[0090] Step 7: Sequentially thermally evaporate 20nm-40nm PCBM and 10-30nm C60 onto the perovskite film.

[0091] Step 8: Deposit a tin dioxide layer as a buffer layer on the surface using a thermal reactive evaporation method, with a thickness of 10nm-20nm. Step 9: Prepare an indium zinc oxide (IZO) layer on the tin oxide buffer layer using magnetron sputtering, with a thickness of 150nm.

[0092] Step 10: Evaporate 5-15 nm of LiF using thermal evaporation as an antireflection layer.

[0093] Step 11: Prepare silver gate lines on the antireflection layer using a conductive gate line template by thermal evaporation, with a thickness of 150nm-300nm.

[0094] Example 3

[0095] As shown in the figure, this invention provides a third method for fabricating silicon / perovskite three-terminal tandem solar cells.

[0096] Step 1: Select a suitable p-type double-sided polished silicon wafer for cleaning.

[0097] Step 2: Use plasma deposition to deposit amorphous silicon on the upper and lower surfaces of the silicon wafer to prepare a passivation layer with a thickness of 5-15 nm.

[0098] Step 3: Using a template for shielding, prepare a tin dioxide electron transport layer on the lower surface via thermal reactive evaporation, with a thickness of 10nm-30nm. Then, evaporate magnesium and aluminum electrodes of the same shape using thermal evaporation, with thicknesses of 10nm-30nm and 200nm-300nm respectively.

[0099] Step 4: Using the complementary template of the above template, prepare a molybdenum oxide hole transport layer with a thickness of 10-20 nm by thermal reaction evaporation in the same way. Based on this, evaporate magnesium and aluminum electrodes of the same shape by thermal evaporation, with thicknesses of 10 nm-30 nm and 200 nm-300 nm, respectively.

[0100] Step 5: Mix the PEDOT:PSS aqueous solution and DMSO solution thoroughly in a certain ratio. After stirring thoroughly, a hole transport layer solution is obtained. Spin coat the silicon wafer surface at a speed of 2000 rpm. After maintaining the rotation for 60 seconds, heat on a heating stage at 130 degrees Celsius for 20 minutes to obtain the hole transport layer. The thickness is preferably 200nm-500nm.

[0101] Step 6: Dissolve lead iodide, methylamine iodide, cesium bromide, and formamidinium iodide in a DMSO / DMF solution in a certain proportion. After thorough stirring and dissolution, filter to obtain the perovskite precursor solution. Spin-coat at 5000 rpm for 20 seconds, then add the antisolvent chlorobenzene dropwise. Continue spin-coating for 30 seconds, then heat on a 100°C heating stage for 50 minutes to complete the preparation of the perovskite absorber layer.

[0102] Step 7: Sequentially thermally evaporate 20nm-40nm PCBM and 10-30nm C60 onto the perovskite film.

[0103] Step 8: Using atomic layer deposition, deposit a layer of tin dioxide as a buffer layer on the surface, with a thickness between 5nm and 10nm.

[0104] Step 9: Prepare an IZO layer with a thickness of 150 nm on the tin oxide buffer layer using magnetron sputtering.

[0105] Step 10: Use electron beam evaporation to evaporate 3-10 nm of LiF as an antireflection layer.

[0106] Step 11: Prepare silver gate lines on the antireflection layer using a conductive gate line template via thermal evaporation, with a thickness of 150nm-300nm. The above description is merely a preferred embodiment of the present invention, but is not limited to the present invention. The scope of patent protection for the present invention should be determined by the claims. Modifications and substitutions to the details of implementation, etc., without departing from the scope of this patent description, should all be included within the scope of protection of the present invention.

Claims

1. A silicon / perovskite three-terminal tandem solar cell, characterized in that, From bottom to top, it includes: a bottom battery and a top battery, wherein, The top cell is a perovskite solar cell unit, which includes, from top to bottom: a first metal electrode layer, a first anti-reflection layer, a first transparent conductive layer, a first transport layer, a first passivation layer, a perovskite absorption layer, and a second transport layer. The bottom cell is a silicon-based solar cell unit with a back-contact structure. The silicon-based solar cell unit with the back-contact structure includes, from top to bottom: a second passivation layer, a silicon substrate, a third transport layer, a fourth transport layer, a second metal electrode layer, and a third metal electrode layer. The third and fourth transport layers are the electron and hole transport layers of the silicon-based solar cell, respectively, and are both located on the back side of the silicon-based solar cell. A second metal electrode layer is disposed on the third transport layer, and a third metal electrode layer is disposed on the fourth transport layer. The second and third metal electrode layers are also located on the back side of the silicon-based solar cell. The first metal electrode layer, the second metal electrode layer, and the third metal electrode layer constitute a three-terminal output structure.

2. The silicon / perovskite three-terminal tandem solar cell according to claim 1, characterized in that, The top cell also includes a first buffer layer; and / or, the bottom cell also includes another second passivation layer.

3. The silicon / perovskite three-terminal tandem solar cell according to claim 1, characterized in that, The first transport layer and the second transport layer are respectively the electron transport layer and the hole transport layer of the perovskite top solar cell, or respectively the hole transport layer and the electron transport layer; wherein, the electron transport layer material is any one of titanium dioxide (TiO2), tin dioxide (SnO2), zinc oxide (ZnO), and C60 (C60); the hole transport layer material is cuprous iodide (CuI) or nickel oxide (NiO). x One of copper thiocyanate (CuSCN).

4. The silicon / perovskite three-terminal tandem solar cell according to claim 1, characterized in that, The silicon substrate is an n-type crystalline silicon substrate or a p-type crystalline silicon substrate, and is any one of the following structures: double-sided polished, single-sided polished, single-sided texturing, or double-sided texturing.

5. The silicon / perovskite three-terminal tandem solar cell according to claim 1, characterized in that, The second passivation layer is required to passivate defects on the surface of the crystalline silicon substrate. The passivation layer material can be any one of amorphous silicon, silicon oxide, or aluminum oxide.

6. The silicon / perovskite three-terminal tandem solar cell according to claim 1, characterized in that, The third and fourth transport layers are the electron transport layer and hole transport layer of the crystalline silicon bottom cell, respectively. The electron transport layer material is any one of n-type silicon, titanium dioxide (TiO2), zinc oxide (ZnO), and tin dioxide (SnO2); the hole transport layer material is p-type silicon, molybdenum trioxide (MoO3), tungsten trioxide (WO3), or vanadium oxide (VO2). x Any one of them.

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