Preparation method of perovskite / crystalline silicon tandem solar cell and cell

Abstract

The application provides a preparation method of a perovskite / crystalline silicon laminated solar cell and the cell. The self-assembled monolayer is blocked from adsorbing on a tunneling layer through a non-full-coverage insulating layer, so as to achieve the effect of a non-full-coverage hole transport layer. On one hand, the lateral conduction network of the hole transport layer can be directly cut off, so that the holes can only migrate longitudinally along the preset transport channel area, and the hole diffusion loss is reduced from the root; on the other hand, the insulating layer is used as a blocking material, and due to the excellent chemical inertness and thermal stability, the insulating layer can be used as a part of interface barrier to inhibit the chemical reaction between the perovskite layer and the SAM layer, slow down the decomposition rate of the perovskite crystal caused by interface erosion, and moreover, the non-full-coverage design can reduce the total amount of SAM molecules by 40%-55%, the SAM molecules in the transport channel area are not densely accumulated, and the problems of transport channel rupture and defect increase caused by molecular aggregation in the traditional structure are avoided.

Description

Technical Field

[0001] This invention relates to the field of perovskite tandem solar cell technology, specifically to a method for fabricating a perovskite / crystalline silicon tandem solar cell and the cell itself. Background Technology

[0002] Solar energy is a promising new clean energy source with advantages such as abundant resources and low cost. Currently, photovoltaic (PV) cells are one of the most efficient ways to convert solar energy into electricity, and monocrystalline silicon and polycrystalline silicon solar cells have relatively mature industrialization technologies. In recent years, perovskite / crystalline silicon tandem technology has become one of the research hotspots in the field of photovoltaic technology, attracting widespread attention. The development of this technology is of great significance for improving the photoelectric conversion efficiency of solar cells and reducing manufacturing costs, thereby promoting the further development and application of solar power generation technology. The theoretical effective photoelectric conversion efficiency of crystalline silicon / perovskite tandem solar cells is as high as 40% or more, far exceeding that of crystalline silicon solar cells. The basic principle of perovskite / crystalline silicon tandem technology is to stack perovskite materials and crystalline silicon materials together to form a heterojunction. By utilizing the wide bandgap, high absorption coefficient, and high carrier mobility of perovskite materials, and the stability and good electron transport performance of crystalline silicon materials, the photoelectric conversion efficiency of solar cells can be improved.

[0003] In practical applications, the photoelectric conversion efficiency of crystalline silicon / perovskite tandem solar cells has exceeded 34%, far surpassing that of traditional single-cell crystalline silicon cells, demonstrating significant commercial value. However, this type of cell currently lacks supporting measured power generation data. The long-term stability of crystalline silicon / perovskite tandem solar cells is currently far inferior to that of crystalline silicon cells, which is a challenge that urgently needs to be addressed. Optimizing the overall cell structure is one of the important directions for improving the photoelectric performance and stability of tandem solar cells. Summary of the Invention

[0004] To address the nonradiative recombination losses and stability degradation caused by molecular aggregation resulting from the lateral conduction of the fully covered hole transport layer in textured crystalline silicon solar cells, this invention provides a method for fabricating a perovskite / crystalline silicon tandem solar cell and a device structure. A non-fully covered insulating layer and a non-fully covered hole transport layer are sequentially fabricated on a textured crystalline silicon structure. The insulating layer fills the textured structure, which on the one hand blocks the lateral conduction of the hole transport layer, reducing nonradiative recombination losses; on the other hand, it reduces the problem of molecular aggregation of the hole transport layer on the textured structure, thus reducing the problems of transport channel breakage and increased defects caused by molecular accumulation.

[0005] To achieve the above objectives, the present invention provides the following specific solution:

[0006] A method for fabricating a perovskite / crystalline silicon tandem solar cell includes the following steps: providing a crystalline silicon bottom cell with a textured surface, and sequentially fabricating a tunneling layer, a partially covered insulating layer, a partially covered hole transport layer, and other films of the perovskite top cell on its surface.

[0007] In one embodiment, the non-full-coverage insulating layer can be prepared by spin coating or spray coating. An insulating layer solution is prepared, deposited onto the crystalline silicon bottom cell, and annealed to obtain the non-full-coverage insulating layer.

[0008] Specifically, the insulating layer solution is obtained by ultrasonically dissolving the insulating layer material in a solvent for 10-30 minutes, with a concentration of 0.5-50 mg / ml. The insulating layer material can be at least one of polymers such as polymethyl methacrylate (PMMA), polyvinyl acetate (PVAc), and polyvinyl alcohol-ethylene copolymer (EVAL). The solvent can be at least one of ethanol, isopropanol, methanol, dimethylformamide (DMF), G-butyrolactone (GBL), dimethyl sulfoxide (DMSO), and N,N-dimethylacetamide (DMA).

[0009] In this embodiment, the non-full-coverage hole transport layer can be prepared by spin coating or spray coating. A hole transport layer solution is prepared, deposited on the non-full-coverage insulating layer, and annealed to obtain the non-full-coverage hole transport layer.

[0010] Specifically, the hole transport layer solution is obtained by ultrasonically dissolving the hole transport layer material in a solvent for 10-30 min, with a concentration of 0.1-50 mg / ml. The hole transport layer material can be a self-assembled small molecule material (SAM) containing at least one of 2PACz, MeO-2PACz, Me-4PACz, MeO-4PACz, and 4PACz. The solvent can be selected from at least one of ethanol, isopropanol, methanol, dimethylformamide (DMF), G-butyrolactone (GBL), dimethyl sulfoxide (DMSO), and N,N-dimethylacetamide (DMA).

[0011] In some embodiments, the crystalline silicon substrate can be prepared by the following steps: providing a textured crystalline silicon substrate, preparing a substrate passivation layer on one side of the textured crystalline silicon substrate, preparing a P-type substrate doped layer on the surface of the substrate passivation layer, preparing a first transparent electrode layer on the surface of the P-type substrate doped layer, preparing a first metal electrode layer on the surface of the first transparent electrode layer; and preparing a substrate surface passivation layer on the other side of the textured crystalline silicon substrate, and preparing an N-type substrate doped layer on the surface of the substrate surface passivation layer.

[0012] In one embodiment, the other films of the perovskite top solar cell include a perovskite absorption layer, a passivation layer, an electron transport layer, a second transparent electrode layer, and a second metal electrode layer sequentially disposed on the non-fully covered hole transport layer.

[0013] In one embodiment, a buffer layer is further provided between the electron transport layer and the second transparent electrode layer.

[0014] In one embodiment, an antireflection layer is further prepared on the second metal electrode layer.

[0015] In another aspect, the present invention provides a perovskite / crystalline silicon tandem solar cell, prepared by the above-described preparation method, comprising, from bottom to top, a crystalline silicon bottom cell with a textured surface, a tunneling layer, a partially covered insulating layer, a partially covered hole transport layer, and other films of the perovskite top cell.

[0016] This application provides a method for fabricating a perovskite / crystalline silicon tandem solar cell. By using a non-fully covered insulating layer to block the adsorption of self-assembled monolayers on the tunneling layer, the effect of a non-fully covered hole transport layer is achieved. On the one hand, the lateral conductive network of the hole transport layer can be directly cut off, allowing holes to migrate only longitudinally along the preset transport channel region, thereby reducing hole diffusion loss at the source. On the other hand, the insulating layer, as a blocking material, can act as a partial "interface barrier" due to its excellent chemical inertness and thermal stability, inhibiting the chemical reaction between the perovskite layer and the SAM layer and slowing down the decomposition rate of the perovskite crystal caused by interface erosion. Moreover, the non-fully covered design can reduce the total amount of SAM molecules by 40%-55%, and the SAM molecules in the transport channel region do not densely accumulate, avoiding problems such as transport channel breakage and increased defects caused by molecular aggregation in traditional structures. Attached Figure Description

[0017] Figure 1 This is a schematic diagram illustrating the fabrication steps of the perovskite / crystalline silicon tandem solar cell described in this invention.

[0018] Figure 2 This is a schematic diagram of the structure of the stacked solar cell described in this invention;

[0019] Figure 3 This is a schematic diagram of the preparation steps of the hole transport layer using traditional methods.

[0020] The labels in the diagram are as follows: 10, Crystalline silicon bottom cell; 20, Perovskite top cell; 21, Partially covered insulating layer; 22, Partially covered hole transport layer; 23, Other films in the perovskite top cell; 30, Tunneling layer;

[0021] 110. First metal electrode layer; 111. First transparent electrode layer; 112. P-type substrate doped layer; 113. Substrate passivation layer; 114. Textured silicon substrate; 115. Substrate surface passivation layer; 116. N-type substrate doped layer;

[0022] 231. Perovskite absorber layer; 232. Passivation layer; 233. Electron transport layer; 234. Buffer layer; 235. Second transparent electrode layer; 236. Second metal electrode layer. Detailed Implementation

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0024] In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "center," "longitudinal," "lateral," "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0025] Please see Figure 3 In the traditional fabrication process of perovskite / crystalline silicon tandem solar cells, a fully covered self-assembled small molecule layer (SAM layer) is used as the hole transport layer of the top cell. This technical structure has significant contradictions and performance shortcomings:

[0026] 1. Nonradiative recombination losses caused by lateral conduction: High-efficiency tandem solar cells exhibit a clear "two-way selectivity" in their performance requirements for the hole transport layer. On the one hand, they need high longitudinal hole conductivity to ensure that photogenerated holes generated in the perovskite layer can be transported to the top electrode quickly and without loss. On the other hand, they need extremely low lateral conductivity to prevent lateral diffusion of holes within the transport layer, thereby suppressing nonradiative recombination at electrode edges or defect regions. However, the molecular structure characteristics of the fully covered SAM hole transport layer fundamentally contradict this requirement—its tightly packed conjugated molecular chains not only realize the construction of longitudinal hole transport channels but also form a continuous lateral conductive network.

[0027] In actual device operation, this lateral conductivity causes two major problems: First, holes diffuse randomly within the transport layer, and some holes fail to reach the top electrode, instead recombinating with electrons inside the transport layer or at the interface, forming a non-radiative recombination current. Second, lateral conduction leads to uneven potential distribution within the device, especially in large-area devices, where the potential difference between the edge and center regions further exacerbates carrier loss. According to the latest research data, this type of loss directly leads to a 50-100mV reduction in the device's open-circuit voltage, a 3-5 percentage point decrease in the fill factor, and ultimately a 2-3 percentage point loss in photoelectric conversion efficiency—a figure that, for current tandem solar cells that have already exceeded 28%, represents a relative efficiency loss of approximately 7%-10%, severely restricting the device's performance from approaching the theoretical limit (33.7%).

[0028] 2. Stability Degradation Due to Molecular Aggregation: In addition to efficiency loss, the fully covered SAM hole transport layer also suffers from significant stability issues, stemming from the dense arrangement of SAM molecules. During SAM film fabrication, molecules are tightly adsorbed onto the perovskite surface through self-assembly, and the van der Waals forces and π-π stacking interactions between adjacent molecules form a highly ordered film structure. However, during long-term device operation, this ordered structure is easily disrupted by the effects of light, temperature fluctuations (especially at high temperatures where the perovskite layer undergoes thermal expansion), and energy transfer during carrier transport: adjacent SAM molecules aggregate due to changes in interfacial energy, forming nanoscale molecular aggregates.

[0029] This aggregation phenomenon triggers a series of chain reactions that directly affect device stability: First, the agglomerates disrupt the continuity of the hole transport layer, leading to the breakage of the longitudinal transport channel, a significant increase in hole transport resistance, and an increase in the device series resistance; second, the agglomerated regions form new interface defects, becoming "trap centers" for carrier recombination, further exacerbating nonradiative recombination losses; finally, the agglomerates may also react with the perovskite layer at the interface, accelerating the decomposition of the perovskite crystal and causing a degradation in the performance of the light absorption layer.

[0030] Given the adverse effects of traditional hole transport layer structures on devices, please refer to [link / reference needed]. Figure 1 This invention provides a method for fabricating a perovskite / crystalline silicon tandem solar cell. The method involves sequentially fabricating a non-fully covered insulating layer, a non-fully covered hole transport layer, and other films of a perovskite top cell on a crystalline silicon bottom cell with a tunneling layer, thereby obtaining a perovskite / crystalline silicon tandem solar cell. The non-fully covered insulating layer is deposited in the valley region of the bottom textured structure, and then self-assembled monoliths are used to cover the peak region of the textured structure in layers, thereby completing the area of ​​the tunneling layer not covered by the non-fully covered insulating layer.

[0031] This application achieves the effect of a non-fully covered hole transport layer by blocking the adsorption of self-assembled monolayers on the tunneling layer through a non-fully covered insulating layer. On the one hand, it can directly cut off the lateral conductive network of the hole transport layer, allowing holes to migrate only longitudinally along the preset transport channel region, thereby reducing hole diffusion loss from the source. On the other hand, the insulating layer, as the blocking material, can act as a partial "interface barrier" due to its excellent chemical inertness and thermal stability, inhibiting the chemical reaction between the perovskite layer and the SAM layer and slowing down the decomposition rate of the perovskite crystal caused by interface erosion. Moreover, the non-fully covered design can reduce the total amount of SAM molecules by 40%-55%, and the SAM molecules in the transport channel region do not densely accumulate, avoiding problems such as transport channel breakage and increased defects caused by molecular aggregation in traditional structures.

[0032] This invention provides a method for fabricating a perovskite / crystalline silicon tandem solar cell, comprising the steps of: providing a crystalline silicon bottom cell 10 with a textured surface structure, and sequentially fabricating a tunneling layer 30, a non-fully covered insulating layer 21, a non-fully covered hole transport layer 22, and other film layers 23 of the perovskite top cell on its surface.

[0033] In one embodiment, the non-full-coverage insulating layer 21 can be prepared by spin coating or spray coating. An insulating layer solution is prepared, deposited onto the crystalline silicon bottom cell 10, and annealed to obtain the non-full-coverage insulating layer 21.

[0034] The insulating layer solution is obtained by ultrasonically dissolving the insulating layer material in a solvent for 10-30 min, with a concentration of 0.5-50 mg / ml. The insulating layer material can be at least one of polymers such as polymethyl methacrylate (PMMA), polyvinyl acetate (PVAc), and polyvinyl alcohol-ethylene copolymer (EVAL). The solvent can be at least one of ethanol, isopropanol, methanol, dimethylformamide (DMF), G-butyrolactone (GBL), dimethyl sulfoxide (DMSO), and N,N-dimethylacetamide (DMA), with a solvent ratio between 0-3:10-7.

[0035] Specifically, when preparing the non-full-coverage insulating layer 21 using spin coating, the spin coating speed can be set to 1000~6000 rpm, the spin coating time to 25~100s, and after spin coating, an annealing operation is performed at a temperature of 50~200℃ for 5~40min.

[0036] Specifically, when the non-full-coverage insulating layer 21 is prepared by spraying, the spraying rate is 1~80cm / s. After spraying, annealing is performed at a temperature of 0~150℃ for a time of 0~30min.

[0037] In this embodiment, the non-full-coverage hole transport layer 22 can be prepared by spin coating or spray coating. A hole transport layer solution is prepared, and the hole transport layer solution is deposited on the non-full-coverage insulating layer 21, followed by annealing to obtain the non-full-coverage hole transport layer 22.

[0038] The hole transport layer solution is obtained by ultrasonically dissolving the hole transport layer material in a solvent for 10-30 min, with a concentration of 0.1-50 mg / ml. The hole transport layer material can be a self-assembled small molecule material (SAM), including but not limited to at least one of 2PACz, MeO-2PACz, Me-4PACz, MeO-4PACz, and 4PACz. The solvent can be selected from at least one of ethanol, isopropanol, methanol, dimethylformamide (DMF), G-butyrolactone (GBL), dimethyl sulfoxide (DMSO), and N,N-dimethylacetamide (DMA), with a solvent ratio between 0-3:10-7.

[0039] Specifically, when preparing the non-full-coverage hole transport layer 22 using spin coating, the spin coating speed can be set to 1000~6000 rpm, the spin coating time to 25~100 s, and after spin coating, an annealing operation is performed at a temperature of 50~200℃ for 5~40 min.

[0040] Specifically, when the non-full-coverage hole transport layer 22 is prepared by spraying, the spraying rate is 1~80cm / s. After spraying, annealing is performed at a temperature of 0~150℃ for a time of 0~30min.

[0041] In this embodiment, the crystalline silicon bottom cell 10 includes, from bottom to top, a first metal electrode layer 110, a first transparent electrode layer 111, a P-type substrate doped layer 112, a substrate passivation layer 113, a textured crystalline silicon substrate 114, a substrate surface passivation layer 115, and an N-type substrate doped layer 116.

[0042] In other embodiments, other crystalline silicon cell structures can also be used as the crystalline silicon base cell 10, such as HJT crystalline silicon structure, BC crystalline silicon structure, etc.

[0043] The crystalline silicon base cell 10 can be prepared by the following steps: providing a textured crystalline silicon substrate 114, preparing a substrate passivation layer 113 on one side of the textured crystalline silicon substrate 114, preparing a P-type substrate doped layer 112 on the surface of the substrate passivation layer 113, preparing a first transparent electrode layer 111 on the surface of the P-type substrate doped layer 112, preparing a first metal electrode layer 110 on the surface of the first transparent electrode layer 111; and preparing a substrate surface passivation layer 115 on the other side of the textured crystalline silicon substrate 114, preparing an N-type substrate doped layer 116 on the surface of the substrate surface passivation layer 115.

[0044] In order to saturate the dangling bonds on the surface of the textured silicon substrate 114, reduce surface activity, increase the surface cleaning process, and avoid the formation of recombination centers due to impurities introduced by the surface layer, thereby reducing the surface recombination rate of minority carriers, a substrate passivation layer 113 and a substrate surface passivation layer 115 can be formed on the two surfaces of the textured silicon substrate 114 by methods such as vapor deposition and atomic layer deposition.

[0045] In one embodiment, a phosphorus source / nitrogen source is used to diffuse on a textured silicon substrate 114 to form a doped structure, thereby obtaining the P-type substrate doped layer 112 and the N-type substrate doped layer 116, respectively.

[0046] In one embodiment, the first transparent electrode layer 111 is prepared by magnetron sputtering, in which the prepared substrate sample is placed in a magnetron sputtering device and the magnetron sputtering power is 50-200W.

[0047] In one embodiment, the first metal electrode layer 110 is deposited using a vapor deposition method, which includes placing the prepared substrate sample on a mask for vapor deposition, with a vapor deposition vacuum degree of 5 × 10⁻⁶. -5 -2×10 -4 Pa, evaporation temperature is 500-2000℃, evaporation rate is 0.1-5Å / S;

[0048] In one embodiment, the tunneling layer 30 is used to address the electrical mismatch and device instability issues arising between two series-connected cells. It can be prepared using one of the following methods: atomic layer deposition, magnetron sputtering, or wet chemical methods.

[0049] In one embodiment, the other films 23 of the perovskite top solar cell include a perovskite absorption layer 231, a passivation layer 232, an electron transport layer 233, a second transparent electrode layer 235, and a second metal electrode layer 236 sequentially disposed on the non-fully covered hole transport layer 22.

[0050] The perovskite absorber layer 231 is produced using a spin-coating flash evaporation method. A perovskite precursor solution is prepared and uniformly coated onto the surface of the non-fully covered hole transport layer 22. The spin-coating speed is 1000-6000 rpm, and the spin-coating time is 20-120 s. After spin-coating, a flash evaporation operation is performed for 10-60 s at a temperature of 0-100℃. After flash evaporation, an annealing treatment is performed at a temperature of 50-150℃ for 5-40 min.

[0051] Furthermore, the perovskite precursor solution contains an ABX3 structure, wherein the A-site is an organic cation, including CH3NH3. + (MA+ ), NH2CH=NH2 + (FA + CH3CH2NH3 + or Cs + At least one of them;

[0052] The B site is a metal cation, including Pb. 2+ Sn 2+ At least one of them;

[0053] The X-position is a halide anion, including F. - Cl - ,Br - I - At least one of them.

[0054] The passivation layer 232 is deposited using a vapor deposition method, which involves evaporating the passivation layer material onto the surface of the perovskite absorber layer 231, with a vapor deposition vacuum degree of 1-5 × 10⁻⁶. -4 The vapor deposition temperature is 50-400℃, and the evaporation rate is 0.05-1 Å / s. After evaporation, annealing is performed at a temperature of 0-150℃ for a time of 0-30 min.

[0055] The passivation layer 232 can also be applied using a spin-coating method. A passivation layer dispersion is prepared and uniformly coated onto the surface of the perovskite absorber layer. The spin-coating speed is 1000-7000 rpm, and the spin-coating time is 20-120 s. After spin-coating, an annealing operation is performed at a temperature of 40-160℃ for 5-40 min.

[0056] The passivation layer 232 can also be applied by spraying, by spraying the passivation layer dispersion onto the perovskite absorption layer at a spraying rate of 0-100 cm / s, and after spraying, performing an annealing operation at a temperature of 20-170℃ and an annealing time of 0-30 min.

[0057] The passivation layer dispersion is prepared by dissolving the passivation layer material in organic solvents including but not limited to methanol, ethanol, or isopropanol, followed by ultrasonic dissolution. The concentration is 0.1-6 mg / ml, and the ultrasonic time is 0-30 min.

[0058] The passivation layer material includes propylenediamine iodine, including but not limited to at least one of propylenediamine bromide (PDADBr), butylamine chloride (BACl), butylamine bromide (BABr), butylamine iodide (BAI), N,N-dimethyl-1,3-propanediamine hydrochloride (DMePDADCl), and dodecylamine bromide (DDDADBr); it may also be at least one of magnesium fluoride, lithium fluoride, and sodium fluoride.

[0059] In one embodiment, the electron transport layer 233 is produced by spin coating, in which the electron transport layer dispersion is uniformly spin-coated onto the surface of the passivation layer 232, with a spin coating speed of 500-4000 rpm and a spin coating time of 10-80 s.

[0060] Optionally, the electron transport layer 233 can also be deposited using a vapor deposition method, whereby the electron transport layer material is evaporated onto the surface of the passivation layer 232, with a vapor deposition vacuum degree of 5 × 10⁻⁶. -5 -5×10 -4 Pa, evaporation temperature is 100-400℃, evaporation rate is 0.05-1Å / S;

[0061] The electron transport layer dispersion comprises at least one solvent in which the electron transport layer material is dissolved in methanol, ethanol, or isopropanol.

[0062] The electron transport layer material includes zinc oxide (ZnO), tin dioxide (SnO2), titanium dioxide (TiO2), and methyl [6,6]-phenyl C61-butyrate (PC). 61 BM), C60 (C 60 At least one of ), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP).

[0063] In one embodiment, the second transparent electrode layer 235 is subjected to magnetron sputtering, which includes sputtering transparent electrode material onto the surface of the electron transport layer 233, with a controlled power of 30-200W.

[0064] Alternatively, the second transparent electrode layer 235 can also be deposited using a vapor deposition method, whereby the transparent electrode material is evaporated onto the surface of the electron transport layer, with a vapor deposition vacuum degree of 1×10⁻⁶. -5 -5×10 -4 Pa, evaporation temperature is 1000-2000℃, evaporation rate is 0.05-3Å / S.

[0065] The first transparent electrode layer 111 and the second transparent electrode layer 235 are one of indium tin oxide, indium zinc oxide, and zinc aluminum oxide;

[0066] The vapor deposition method used for the second metal electrode layer 236 is similar to that of the first metal electrode layer, except that the mask is different.

[0067] The first metal electrode layer 110 and the second metal electrode layer 236 are one of silver, gold, copper, aluminum and carbon.

[0068] In one embodiment, a buffer layer 234 is further provided between the electron transport layer 233 and the second transparent electrode layer 235.

[0069] In one embodiment, the buffer layer 234 is constructed using atomic layer deposition, which involves depositing the buffer layer material onto the surface of the electron transport layer 233 using an atomic layer deposition apparatus, with a deposition vacuum degree of 0-1×10⁻⁶. 4 Pa, the temperature of the deposition pipe is between 50-150℃, and the temperature of the deposition chamber is between 40-150℃;

[0070] Optionally, the buffer layer 234 can also be deposited using a vapor deposition method, whereby the buffer layer material is evaporated onto the surface of the electron transport layer 233, with a vapor deposition vacuum degree of 6×10⁻⁶. -5 -4×10 -4 Pa, evaporation temperature is 100-500℃, evaporation rate is 0.05-1Å / S;

[0071] Specifically, the buffer layer material includes at least one of zinc oxide (ZnO), tin dioxide (SnO2), and titanium dioxide (TiO2).

[0072] In one embodiment, an antireflection layer (not shown) is further prepared on the second metal electrode layer 236.

[0073] Specifically, the antireflection layer can be prepared by magnetron sputtering or vapor deposition.

[0074] The antireflective layer is at least one of magnesium fluoride, lithium fluoride (LiF), sodium fluoride (NaF), and silicon oxide (SiO2).

[0075] In another aspect, the present invention provides a perovskite / crystalline silicon tandem solar cell, which is prepared by the above-described preparation method and includes, from bottom to top, a crystalline silicon bottom cell 10 with a textured surface, a tunneling layer 30, a partially covered insulating layer 21, a partially covered hole transport layer 22, and other film layers 23 of the perovskite top cell.

[0076] The following specific embodiments and comparative examples clearly and completely describe the technical solution of the present invention. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0077] Example 1

[0078] Please see Figures 1-2This embodiment provides a perovskite / crystalline silicon tandem solar cell, including a crystalline silicon bottom cell 10, a tunneling layer 20, and a perovskite top cell 30. The crystalline silicon bottom cell 10, from bottom to top, includes a first metal electrode layer 110, a first transparent electrode layer 111, a P-type substrate doped layer 112, a substrate passivation layer 113, a textured crystalline silicon substrate 114, a substrate surface passivation layer 115, and an N-type substrate doped layer 116. The perovskite top cell, from bottom to top, includes a non-fully covered insulating layer 21, a non-fully covered hole transport layer 22, a perovskite absorption layer 231, a passivation layer 232, an electron transport layer 233, a buffer layer 234, a second transparent electrode layer 235, a second metal electrode layer 236, and an anti-reflection layer. The fabrication method of the tandem solar cell includes the following steps:

[0079] S(1) Provide a textured silicon substrate 114, prepare a substrate passivation layer 113 on the back side of the textured silicon substrate 114, and form a P-type substrate doped layer 112 by diffusion through a phosphorus source in the substrate passivation layer 113; prepare a substrate surface passivation layer 115 on the surface of the textured silicon substrate 114, and form an N-type substrate doped layer 116 by diffusion through a nitrogen source in the substrate surface passivation layer 115.

[0080] S(2), Preparation of the first transparent electrode layer 111:

[0081] The first transparent electrode layer 111 is prepared on the surface of the above-mentioned P-type substrate doped layer 112 by magnetron sputtering. The thickness of the first transparent electrode layer 111 is 100 nm. The target material for magnetron sputtering is indium tin oxide (ITO), the power of magnetron sputtering is 60 W, and the running time of magnetron sputtering is 1.5 h.

[0082] S(3), Preparation of the first metal electrode layer 110:

[0083] The substrate sample prepared in the previous step is placed on a mask, and silver (Ag) is deposited onto the surface of the first transparent electrode layer 111 using a vapor deposition method to prepare the first metal electrode layer 110. The thickness of the first metal electrode layer 110 is 200 nm, and the vacuum degree of the vapor deposition method is 2 × 10⁻⁶. -4 Pa, temperature 800℃, evaporation rate 2.5 Å / S.

[0084] S(4), Preparation of tunneling layer 30:

[0085] A tunneling layer 30 is prepared on the surface of the N-type substrate doped layer 116, the thickness of the tunneling layer 30 is 40 nm, and the magnetron sputtering power is 60 W and the running time is 1 h.

[0086] S(5), Preparation of the non-full-coverage insulating layer 21 and the non-full-coverage hole transport layer 22:

[0087] The insulating layer solution was prepared by spin coating. PMMA was dissolved in IPA and ultrasonically dissolved at a concentration of 1 mg / ml for 10 min. Then spin coating was performed at a speed of 6000 rpm for 25 s. After spin coating, annealing was performed at a temperature of 100℃ for 10 min to form a non-full-coverage insulating layer 21 on the tunneling layer 30.

[0088] The hole transport layer solution was prepared by spin coating. 2PACz was dissolved in IPA and sonicated for 10 min. Then spin coating was performed at 6000 rpm for 25 s. After spin coating, annealing was performed at 100℃ for 10 min.

[0089] S(6), Preparation of perovskite absorber layer 231:

[0090] The perovskite layer 231 was prepared by flash evaporation, including the following steps: dissolving perovskite powder with an ABX3 structure in 1 ml of DMF and DMSO solvent in a solvent ratio of 8:2, stirring to obtain a perovskite precursor solution, placing the battery substrate on a spin coater, setting the spin coater speed to 3500 rpm and the spin coater time to 30 s, coating the surface of the battery substrate with 120 μL of the perovskite precursor solution, transferring it to a flash evaporation stage after spin coatering, setting the flash evaporation time to 30 s and the flash evaporation temperature to 30 °C, and performing annealing treatment after flash evaporation, setting the annealing temperature to 100 °C and the annealing time to 15 min, to obtain the perovskite absorber layer 231 with a thickness of approximately 500 nm.

[0091] S(7), Preparation of passivation layer 232:

[0092] Using the vapor deposition method, 3 mg of propylenediamine iodine was weighed and placed in a crucible. The sample obtained in the above steps was placed on a mask and then placed in the vapor deposition chamber. The vapor deposition vacuum was maintained at 2 × 10⁻⁶. -4 Evaporation was performed at Pa, the evaporation voltage was adjusted to the evaporation temperature, and the evaporation rate was controlled at 0.1 Å / S. Propylene diamine iodine was deposited onto the film with a thickness of 4 nm. After the evaporation, the annealing station temperature was set to 100℃ and annealing was performed for 8 minutes.

[0093] S(8), Fabrication of electron transport layer 233:

[0094] C 60 The electron transport layer 233 is prepared by evaporation onto the surface of the passivation layer 232. The thickness of the electron transport layer 233 is 20 nm, and the vacuum degree of the evaporation is 1 × 10⁻⁶. -4Pa, evaporation temperature at 200℃, evaporation rate at 0.1 Å / S.

[0095] S(9), Preparation of buffer layer 234:

[0096] SnO2 was deposited onto the surface of the electron transport layer 233 using atomic layer deposition (ALD) equipment to prepare the buffer layer 234, which has a thickness of 15 nm. The vacuum degree of the deposition was 0.5 × 10⁻⁶. 4 Pa, the temperature of the deposition pipe is 70℃, and the temperature of the deposition chamber is 60℃.

[0097] S(10), Preparation of the second transparent electrode layer 235:

[0098] The second transparent electrode layer 235 is prepared on the surface of the buffer layer 234 by magnetron sputtering. The thickness of the second transparent electrode layer 235 is 100 nm. The target material for magnetron sputtering is indium zinc oxide (IZO), the power of magnetron sputtering is 50 W, and the running time of magnetron sputtering is 1 h.

[0099] S(11), Preparation of the second metal electrode layer 236:

[0100] The substrate sample prepared in the previous step is placed on a mask. Silver (Ag) is deposited onto the surface of the second transparent electrode layer 235 using a vapor deposition method to prepare the second metal electrode layer 236. The thickness of the second metal electrode layer 236 is 100 nm, and the vacuum degree of the vapor deposition is 2 × 10⁻⁶. -4 Pa, temperature 800℃, evaporation rate 0.1 Å / S.

[0101] S(12), Preparation of the antireflective layer:

[0102] The substrate sample prepared in the previous step is placed on a photomask. Magnesium fluoride is evaporated onto the surface of the second metal electrode layer 236 using a vapor deposition method, and then annealed to prepare the antireflection layer. The thickness of the antireflection layer is 100 nm, wherein the vapor deposition vacuum degree is 2 × 10⁻⁶. -4 The perovskite / crystalline silicon tandem solar cell was obtained by evaporation at 80℃, evaporation rate at 2Å / s, annealing temperature at 100℃, and annealing time at 8min.

[0103] Example 2

[0104] The preparation process of this embodiment is the same as that of the stacked solar cell described in Embodiment 1, except that the concentration of the insulating layer solution in step S (5) of this embodiment is 5 mg / mL.

[0105] Example 3

[0106] The preparation process of this embodiment is the same as that of the stacked solar cell described in Embodiment 1, except that the concentration of the insulating layer solution in step S (5) of this embodiment is 10 mg / mL.

[0107] Comparative Example 1

[0108] In this comparative example, the tandem solar cell uses a traditional hole transport layer fabrication process, which is basically the same as that in Example 1. The difference is that in this comparative example, a non-fully covered insulating layer is not prepared in step S(5). The specific steps are as follows:

[0109] S(5), Preparation of hole transport layer:

[0110] The hole transport layer was prepared using a spin-coating method. A hole transport layer solution was prepared by dissolving 2 PACz in IPA and then sonicating it. The concentration was 1 mg / ml, and the sonication time was 10 min. Then, spin-coating was performed at 6000 rpm for 25 s. After spin-coating, annealing was performed at 100℃ for 10 min.

[0111] In Comparative Example 1, since there is no insulating layer as a barrier, the spin-coated hole transport layer will completely cover the surface of the tunneling layer, such as... Figure 3 As shown.

[0112] The perovskite / crystalline silicon tandem solar cells obtained in Examples 1-3 and Comparative Example 1 were tested under the following conditions: a standard solar intensity calibration was performed using a solar simulator, and the solar cells with an area of ​​1.0 cm² were tested. 2 The device in this embodiment underwent a long-term IV test, with the starting voltage set to 2V, the cutoff voltage to 0V, and the range to 100mA. The results were rounded to one decimal place. The test results are shown in Table 1 below.

[0113] Table 1 shows the performance of the tandem solar cells described in Examples 1-3 and Comparative Example 1.

[0114] Device open-circuit voltage (V) Device fill factor Device photoelectric conversion efficiency (%) Decay rate (% / year) Example 1 1.96 0.81 32.1 0.5% Example 2 1.98 0.82 33.6 0.4% Example 3 1.98 0.65 25.4 0.5% Comparative Example 1 1.92 0.78 31.1 6.4%

[0115] As shown in Table 1, compared with the traditional device (i.e., the one obtained in Comparative Example 1), the device obtained using this method (i.e., Examples 1-3) has improved its open-circuit voltage and reduced its annual decay rate, thus improving the overall operating stability of the device. This application uses an insulating layer to construct a barrier region that cuts off the lateral conductive network of the SAM layer, allowing holes to migrate only longitudinally along a preset transmission channel region, precisely suppressing non-radiative recombination. For example, in Example 2, when the insulating layer concentration is 5 mg / ml, unnecessary charge recombination is effectively blocked to increase the voltage, while ensuring efficient current transmission, resulting in a fill factor of 0.82 and a photoelectric conversion efficiency as high as 33.6%, which is the optimal state. Example 1 also shows good performance, with a fill factor of 0.81 and a photoelectric conversion efficiency of 32.1%. On the other hand, the insulating layer (such as PMMA), acting as an "interface barrier," inhibits the chemical reaction between the perovskite layer and the SAM layer due to its excellent chemical inertness and thermal stability, slowing down the decomposition of the perovskite crystal. Furthermore, the non-full-coverage design reduces the total amount of SAM molecules by 40%-55%, avoiding problems such as transmission channel breakage caused by molecular aggregation in traditional structures (the insulating layer fills the recessed parts of the textured structure, reducing the aggregation problem of traditional SAMs layers in recessed structures), thus improving stability. However, in Example 3, the excessively thick insulating layer severely hindered current transmission, causing the fill factor to plummet to 0.65 and the photoelectric conversion efficiency to only 25.4%. This conversely verifies that the insulating layer concentration needs precise control to ensure that the present invention significantly improves the device's open-circuit voltage, fill factor, and photoelectric conversion efficiency within a reasonable parameter range, while also greatly enhancing stability and reducing the annual degradation rate.

[0116] The above embodiments are merely preferred embodiments of the present invention. It should be noted that, for those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle of the present invention. All technical solutions after making equivalent substitutions to the claims of the present invention fall within the protection scope of the present invention, which is defined by the appended claims and their equivalents.

Claims

1. A method for fabricating a perovskite / crystalline silicon tandem solar cell, characterized in that, The steps include: providing a crystalline silicon bottom cell with a textured surface, and sequentially fabricating a tunneling layer, a partially covered insulating layer, a partially covered hole transport layer, and other perovskite top cell films on its surface; The non-full-coverage hole transport layer is a self-assembled monolayer. The non-full-coverage insulating layer is deposited in the valley area of ​​the bottom textured structure, and then the peak area of ​​the textured structure is covered by the self-assembled monolayer, thereby completing the area of ​​the tunneling layer that is not covered by the non-full-coverage insulating layer.

2. The method for fabricating a perovskite / crystalline silicon tandem solar cell according to claim 1, characterized in that, The non-full-coverage insulating layer is prepared by spin coating or spray coating. An insulating layer solution is prepared, deposited onto the crystalline silicon bottom cell, and annealed to obtain the non-full-coverage insulating layer.

3. The method for fabricating a perovskite / crystalline silicon tandem solar cell according to claim 1, characterized in that, The non-full-coverage hole transport layer is prepared by spin coating or spray coating. A hole transport layer solution is prepared, and the hole transport layer solution is deposited on the non-full-coverage insulating layer and annealed to obtain the non-full-coverage hole transport layer.

4. The method for fabricating a perovskite / crystalline silicon tandem solar cell according to claim 2, characterized in that, The insulating layer solution is obtained by ultrasonically dissolving the insulating layer material in a solvent for 10-30 min, with a concentration of 0.5-50 mg / ml. The insulating layer material is at least one of polymethyl methacrylate (PMMA), polyvinyl acetate (PVAc), and polyvinyl alcohol-ethylene copolymer (EVAL). The solvent is selected from at least one of ethanol, isopropanol, methanol, dimethylformamide (DMF), G-butyrolactone (GBL), dimethyl sulfoxide (DMSO), and N,N-dimethylacetamide (DMA).

5. The method for fabricating a perovskite / crystalline silicon tandem solar cell according to claim 3, characterized in that, The hole transport layer solution is obtained by ultrasonically dissolving the hole transport layer material in a solvent for 10-30 min, with a concentration of 0.1-50 mg / ml. The hole transport layer material is a self-assembled small molecule material (SAM) containing at least one of 2PACz, MeO-2PACz, Me-4PACz, MeO-4PACz, and 4PACz. The solvent is selected from at least one of ethanol, isopropanol, methanol, dimethylformamide (DMF), G-butyrolactone (GBL), dimethyl sulfoxide (DMSO), and N,N-dimethylacetamide (DMA).

6. The method for fabricating a perovskite / crystalline silicon tandem solar cell according to claim 1, characterized in that, The crystalline silicon bottom cell is prepared by the following steps: a textured crystalline silicon substrate is provided, a substrate passivation layer is prepared on one side of the textured crystalline silicon substrate, a P-type substrate doped layer is prepared on the surface of the substrate passivation layer, a first transparent electrode layer is prepared on the surface of the P-type substrate doped layer, and a first metal electrode layer is prepared on the surface of the first transparent electrode layer. A substrate surface passivation layer is prepared on the other side of the textured silicon substrate, and an N-type substrate doped layer is prepared on the surface of the substrate surface passivation layer.

7. The method for fabricating a perovskite / crystalline silicon tandem solar cell according to claim 1, characterized in that, The other films of the perovskite top solar cell include a perovskite absorption layer, a passivation layer, an electron transport layer, a second transparent electrode layer, and a second metal electrode layer, which are sequentially disposed on the non-fully covered hole transport layer.

8. The method for fabricating a perovskite / crystalline silicon tandem solar cell according to claim 7, characterized in that, It also includes a buffer layer disposed between the electron transport layer and the second transparent electrode layer.

9. The method for fabricating a perovskite / crystalline silicon tandem solar cell according to claim 7, characterized in that, It also includes preparing an antireflection layer on the second metal electrode layer.

10. A perovskite / crystalline silicon tandem solar cell, prepared by the method according to any one of claims 1 to 9, characterized in that, It includes, from bottom to top, a crystalline silicon bottom cell with a textured surface, a tunneling layer, a partially covered insulating layer, a partially covered hole transport layer, and other films for the perovskite top cell.

Images