Perovskite tandem cell and method of manufacturing the same

Abstract

The application discloses a perovskite laminated battery and a preparation method thereof. The perovskite laminated battery comprises a bottom battery and a top battery arranged on the bottom battery. The top battery comprises, from bottom to top, a hole transport layer, a perovskite layer, an interface modification layer, an electron transport layer and a top electrode. The interface modification layer is a layer of nano metal oxide particles coated with an organic material. The absorption rate of the interface modification layer to ultraviolet light is greater than or equal to 95%. The conversion rate of the interface modification layer to visible light converted from ultraviolet light is greater than or equal to 75%. The haze value of the interface modification layer is greater than or equal to 45%. The interface modification layer is introduced into the laminated battery, so that the influence of ultraviolet light on the perovskite layer can be avoided, the electron extraction efficiency is not affected, the interface contact is optimized, and the transport of photo-generated carriers is promoted.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic technology, specifically relating to a perovskite tandem solar cell and its preparation method. Background Technology

[0002] Perovskite tandem solar cells have become a research hotspot in the photovoltaic field due to their excellent photoelectric conversion performance. This high efficiency is mainly attributed to the broad spectral absorption capacity of perovskite materials in the visible light range and their efficient transport characteristics for photogenerated carriers. Furthermore, perovskite tandem solar cells are diverse, classified according to their device structure into mesoporous and planar (nip and pin structures), providing multiple avenues for optimizing cell performance. In recent years, researchers have further improved the stability and efficiency of perovskite tandem solar cells through techniques such as passivation engineering, additive engineering, and interface modification. However, despite significant progress in laboratory applications, perovskite tandem solar cells still face many challenges in practical applications, particularly regarding environmental stability.

[0003] In perovskite / heterojunction solar cells, perovskite materials or heterojunction layers are prone to generating defect states (such as I vacancies, Pb vacancies) under ultraviolet (UV) irradiation. 2+ Ion migration leads to a decrease in photoelectric conversion efficiency (UVID problem), which is one of the key factors limiting the long-term stability of perovskite tandem solar cells.

[0004] Therefore, how to effectively suppress the effects of ultraviolet radiation on perovskite tandem solar cells has become an important research topic. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a perovskite tandem solar cell and its preparation method.

[0006] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a perovskite tandem solar cell, comprising a bottom cell and a top cell disposed on the bottom cell, the top cell comprising, from bottom to top, a hole transport layer, a perovskite layer, an interface modification layer, an electron transport layer and a top electrode, wherein: The interface modification layer is an organic material coating of nano-metal oxide particles.

[0007] In this invention: The interface modification layer has an absorption rate of ≥95% for ultraviolet light, such as 95%, 96%, 97%, 98%, 99%, etc., preferably 95-99%; The interface modification layer has a conversion rate of ≥75% for ultraviolet light to visible light, such as 75%, 78%, 80%, 82%, 85%, 88%, 90%, etc., preferably 75-90%; The haze value of the interface modification layer is ≥45%, such as 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, etc., preferably 45-85%.

[0008] This invention, by introducing an interface modification layer into the stacked battery, has the following advantages: i. The present invention relates to a tandem battery, wherein an interface modification layer is disposed between the perovskite layer and the electron transport layer. The interface modification layer has an absorption rate of 95% or higher for ultraviolet light (wavelength 300-400 nm), thus effectively avoiding the influence of ultraviolet light on the perovskite layer. ii. The nano-metal oxide particles in the interface modification layer of the present invention can absorb harmful ultraviolet light and convert it into visible light or heat energy. The conversion rate of ultraviolet light to visible light (wavelength of 400-700 nm) can reach 75% or more, which can reduce the destructive effect of ultraviolet light on the perovskite layer. iii. The interface modification layer of the present invention forms an organic material coating layer on the surface of nano-metal oxide particles. On the one hand, the organic material has good flexibility and film-forming properties. When it is coated on the surface of nano-metal oxide particles, it can avoid the influence of environmental factors on the nano-metal oxide particles. On the other hand, the combination of organic material and nano-metal oxide particles can significantly enhance the absorption and conversion ability of the interface modification layer to ultraviolet light and improve the stability of the interface modification layer. iv. Functional groups in organic materials (such as hydroxyl and carboxyl groups) can not only form chemical bonds with the surface of nano-metal oxide particles, but also may form chemical bonds with the electron transport layer and perovskite layer, optimizing interfacial contact and promoting the transport of photogenerated carriers. Therefore, by introducing an interface modification layer into the tandem battery, the present invention can avoid the influence of ultraviolet light on the perovskite layer without affecting the electron extraction efficiency, and can also optimize the interface contact and promote the transport of photogenerated carriers.

[0009] In this invention, the method for testing the absorption rate of ultraviolet light by the interface modification layer is a UV-Vis spectrophotometer; the method for testing the conversion rate of ultraviolet light to visible light by the interface modification layer is a photoluminescence spectrometer; and the method for testing the haze value of the interface modification layer is a haze meter or a spectrophotometer (equipped with an integrating sphere).

[0010] In this invention, if the haze value is too low, the interface modification layer is too transparent and flat, and the incident light mainly passes through in a direct manner, failing to form effective diffuse reflection and total reflection within the perovskite layer, i.e., light capture fails, and the problem of insufficient absorption of the perovskite layer in the long wavelength region cannot be solved, resulting in a lack of significant improvement in the short-circuit current density (Jsc) of the battery. If the haze value is too high, it leads to transmittance and electrical loss, and the overall transmittance decreases (a large amount of light is reflected back into the air or lost through lateral scattering). At the same time, excessively high haze often means that the concentration of nanoparticles is too high or that they have agglomerated, which will seriously damage the continuity of the interface modification layer, increase the series resistance (Rs) of the device, cause a significant decrease in the fill factor (FF), and even cause poor contact between the top electrode and the lower layer.

[0011] Preferably, the light scattering cross-section value of the interface modification layer is ≥1.5×10⁻⁶. -10 cm 2 For example, 1.5 × 10 -10 cm 2 2×10 -10 cm 2 2.5×10 -10 cm 2 3×10 -10 cm 2 The preferred value is 1.5 × 10⁻⁶. -10 -3×10 -10 cm 2 .

[0012] Preferably, the effective optical path length extension factor of the interface modification layer is ≥1.15, such as 1.15, 1.2, 1.25, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, etc., and more preferably 1.15-1.8.

[0013] Furthermore, the interface modification layer introduced in this invention constructs a highly efficient light scattering grid. This light scattering grid enables incident light to undergo multiple diffuse and total reflections after entering the perovskite active layer, effectively extending the effective optical path of photons, compensating for the low absorption coefficient of the perovskite layer in the long wavelength region, and enhancing the light absorption efficiency.

[0014] In this invention, the light scattering cross section value is tested using a dynamic light scattering instrument and a UV-Vis spectrophotometer; the effective optical path length extension factor is tested using a UV-Vis spectrophotometer (equipped with an integrating sphere) and a thin film thickness gauge.

[0015] If the light scattering cross-section is too small, meaning the nanoparticle size is too small (close to the molecular level) or the refractive index difference between the particles and the organic matrix is ​​extremely small, then the nanoparticles cannot act as effective "light scattering centers," and the modified layer, acting as an "ordinary transparent polymer film," loses its light-trapping function, i.e., the scattering center fails. If the light scattering cross-section is 3 × 10⁻⁶, then the nanoparticles cannot act as effective "light scattering centers," and the modified layer, acting as an "ordinary transparent polymer film," loses its light-trapping function; in other words, the scattering center fails.-10 cm 2 The large particle size of the nano-metal oxide particles results in a rougher surface of the modified layer, which easily introduces grain boundary defects and pores, forming non-radiative recombination centers and lowering the open-circuit voltage (Voc).

[0016] If the effective optical path length extension factor is too small, it indicates that the light travels almost "straight in and out" in the active layer. A small optical path gain usually cannot be converted into a detectable increase in photocurrent (it will be masked by experimental errors), meaning the interface modification layer is an "ineffective" modification layer. If the effective optical path length extension factor is above 1.8, it indicates that the light is "trapped" in the battery for a longer time. Although this increases the probability of perovskite absorption, it may also be absorbed by the inactive layer and converted into heat energy, potentially leading to a decrease in collection efficiency.

[0017] Preferably, the organic material comprises an alkenyl polymer, more preferably comprising polyacrylic acid materials and / or polyenol materials, and more preferably a combination of polyacrylic acid materials and polyenol materials, wherein the polyacrylic acid material comprises polymethyl methacrylate (PMMA) and the polyenol material comprises polyvinyl alcohol (PVA), preferably a combination of polymethyl methacrylate and polyvinyl alcohol.

[0018] The present invention preferably uses PMMA and / or PVA, which has the following advantages: i. PMMA contains a large number of ester groups in its molecular chain, which endows the material with good flexibility and film-forming properties. The good flexibility enables it to effectively encapsulate nano-metal oxide particles and reduce the influence of external environmental factors on the nano-metal oxide particles. At the same time, its film-forming properties help to form a uniform interface modification layer and improve the overall stability of the interface modification layer. Its high transparency and optical properties help to enhance the ability of nano-metal oxide particles to absorb and convert ultraviolet light. Furthermore, the introduction of PMMA can also significantly improve the surface hardness of the interface modification layer. Therefore, by introducing PMMA, this invention enables the interface modification layer to have excellent stability and excellent ultraviolet light absorption and conversion capabilities. ii. The PVA molecular structure contains a large number of hydroxyl functional groups, which can interact with the active sites on the surface of nano-metal oxide particles, thereby promoting interfacial bonding between the two and increasing the dispersion uniformity of the nano-metal oxide particles. At the same time, the large number of hydroxyl functional groups can also endow PVA with excellent hydrophilicity and film-forming properties. Excellent hydrophilicity makes it easy to mix with other functional materials to prepare slurries, while excellent film-forming properties can effectively encapsulate nano-metal oxide particles, isolate them from environmental factors such as oxygen and moisture, and significantly improve the long-term stability of the material. Moreover, the hydrogen bonding effect of PVA can also increase the dispersibility of PVA and the mechanical strength of the film after formation. Therefore, by introducing PVA, this invention can also make the interface modification layer have excellent stability and excellent ultraviolet light absorption and conversion capabilities.

[0019] Furthermore, the present invention preferably introduces PMMA and PVA simultaneously, which work together to synergistically enhance the interface modification layer with the nano-metal oxide particles, thereby giving the interface modification layer a better application effect.

[0020] Preferably, the mass ratio of the polyacrylic acid material to the polyvinyl alcohol material is 1:(0.3-3), and more preferably, the mass ratio of the polymethyl methacrylate to polyvinyl alcohol is 1:(0.3-3), such as 1:0.3, 1:0.4, 1:0.5, 1:0.8, 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, 1:2.2, 1:2.5, 1:2.8, 1:3, etc.

[0021] Preferably, the average molecular weight of the polymethyl methacrylate is 50,000-500,000, such as 50,000, 60,000, 80,000, 100,000, 200,000, 300,000, 400,000, 500,000, etc.

[0022] Preferably, the average molecular weight of the polyvinyl alcohol is 31,000-50,000, such as 31,000, 35,000, 38,000, 40,000, 42,000, 45,000, 48,000, 50,000, etc.

[0023] Preferably, the nano-metal oxide particles include any one or a combination of at least two of nano-zinc oxide, cerium oxide, or iron oxide, with nano-zinc oxide being the most preferred.

[0024] Preferably, the particle size D50 of the nano-metal oxide particles is 3-5 nm, such as 3 nm, 3.5 nm, 4 nm, 4.5 nm, 5 nm, etc.

[0025] In this invention, if the particle size of the nano-metal oxide particles is large, it will affect the formation of the interface modification layer.

[0026] The particle size D50 of the nano-metal oxide particles described in this invention is tested by laser particle size analysis or transmission electron microscopy.

[0027] Preferably, the mass ratio of the organic material to the nano-metal oxide particles is 1:(0.5-7), such as 1:0.5, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, etc., and preferably 1:(0.5-1).

[0028] Preferably, the thickness of the interface modification layer is 5-15 nm, such as 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, etc.

[0029] If the interface modification layer is too thin, it cannot completely cover the perovskite layer, resulting in the inability to achieve excellent ultraviolet light absorption and conversion effects; if the interface modification layer is too thick, it will hinder carrier transport (resistance increases sharply) and generate additional parasitic absorption, reducing current output.

[0030] The thickness of the interface modification layer described in this invention is tested using SEM electron microscopy.

[0031] Preferably, the electron transport layer is a C60 electron transport layer.

[0032] When the electron transport layer is a C60 electron transport layer, the interface modification layer described in this invention has better compatibility with other layers of the perovskite tandem solar cell. It can match the electron transport layer (C60) and the perovskite layer, avoiding charge accumulation and nonradiative recombination caused by energy level shift at the interface.

[0033] Meanwhile, the interface modification layer provided by the present invention has excellent chemical stability. It will not decompose or decomposes very little under long-term light and high temperature conditions, which can avoid the decomposition products from causing corrosion and other effects on the perovskite layer.

[0034] In a second aspect, the present invention provides a method for preparing a perovskite tandem solar cell as described in the first aspect, the method comprising: S1. Provides a base battery; S2. A hole transport layer, a perovskite layer, an interface modification layer, an electron transport layer, and a top electrode are sequentially fabricated on the bottom cell to obtain the perovskite tandem cell.

[0035] Preferably, the method for preparing the interface modification layer includes: preparing a slurry containing organic materials and nano-metal oxide particles, coating, and curing to obtain the interface modification layer.

[0036] Preferably, the concentration of the nano-metal oxide particles in the slurry is 0.5-2.5 mg / mL, such as 0.5 mg / mL, 0.8 mg / mL, 1 mg / mL, 1.2 mg / mL, 1.5 mg / mL, 1.8 mg / mL, 2 mg / mL, 2.2 mg / mL, 2.5 mg / mL, etc., and more preferably 1-2 mg / mL.

[0037] Preferably, the method for preparing the slurry includes: The organic material is dissolved in a solvent to obtain solution A. The nano-metal oxide particles are dispersed in the same solvent to obtain dispersion B. Solution A and dispersion B are mixed at a mass ratio of organic material to nano-metal oxide particles of 1:(0.5-7) to obtain the slurry.

[0038] Preferably, the coating method includes spin coating; the coating (spin coating) is carried out in a nitrogen-protected glove box to avoid adverse effects of oxygen and moisture in the air on the film quality.

[0039] Preferably, the method for preparing the interface modification layer specifically includes: A slurry is prepared, and the mixed solution is evenly spread on the surface of the perovskite layer by spin coating. After annealing and curing, the interface modification layer is obtained.

[0040] Preferably, the spin coating rate is 4000-5000 rpm, such as 4000 rpm, 4200 rpm, 4500 rpm, 4600 rpm, 4800 rpm, 5000 rpm, etc., and the time is 30-40 s, such as 30 s, 32 s, 35 s, 36 s, 38 s, 40 s, etc.

[0041] Preferably, the annealing and curing temperature is 90-100℃, such as 90℃, 92℃, 95℃, 96℃, 98℃, 100℃, etc., and the time is 10-15 min, such as 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, etc. In this invention, annealing and curing can remove residual solvents and enhance the adhesion of the film.

[0042] Compared with the prior art, the present invention has the following beneficial effects: This invention introduces an interface modification layer into the tandem battery, which can avoid the influence of ultraviolet light on the perovskite layer without affecting the electron extraction efficiency, and can also optimize the interface contact and promote the transport of photogenerated carriers. Detailed Implementation

[0043] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0044] Unless otherwise specified, the raw materials involved in the following specific embodiments of the present invention are all conventional materials in the art, and can be purchased from commercially available products. Some raw material information is as follows: Polymethyl methacrylate-1: PMMA-1, molecular weight 100,000, purchased from Maclean's; Polymethyl methacrylate-2: PMMA-2, molecular weight 400,000, purchased from Aladdin; Polyvinyl alcohol-1: PVA-1, molecular weight 35000, purchased from Maclean's; Polyvinyl alcohol-2: PVA-2, molecular weight 40,000, purchased from Aladdin; Nano Zinc Oxide Particles-1: Nano ZnO particles-1, with a particle size D50 of 3 nm, purchased from Maclean; Nano zinc oxide particles-2: Nano ZnO particles-2, with a particle size D50 of 5 nm, purchased from Aladdin.

[0045] Example 1 This embodiment provides a perovskite / crystalline silicon heterojunction tandem solar cell and its fabrication method, as follows: S1. Fabrication of the bottom cell S11. A 150 μm thick N-type single crystal silicon is sequentially pre-cleaned with ozone and deionized water, post-cleaned with an ozone-hydrofluoric acid mixed solution, and finally cleaned and etched with a hydrofluoric acid-nitric acid mixed solution to form an N-type crystal silicon wafer with double-sided textured surface. S12. A 2 nm intrinsic hydrogenated amorphous silicon passivation layer is deposited on both sides of the N-type crystalline silicon wafer by PECVD to form the first passivation layer. Then, a 9 nm P-type hydrogenated amorphous silicon doped layer and a 6 nm N-type hydrogenated amorphous silicon doped layer are deposited on both sides to form the second passivation layer, thereby achieving a symmetrical bifacial cell structure. S2. Fabrication of top cell S21. Deposit an IZO layer (10 nm) on the surface of an N-type hydrogenated amorphous silicon doped layer. S22. Prepare an ethanol solution of 1 mg / mL Meo-4PACz, spin-coat it on the surface of the IZO layer at 3000 rpm for 30 s, and then anneal it at 100℃ for 10 min to obtain a hole transport layer with a thickness of 5 nm. S23. 1.6M (CH(NH2)2PbI3) 0.83 Cs 0.17 Pb(I 0.82Br 0.18 )3 (1.68 eV) solvent DMF:DMSO4:1, annealed at 100℃ for 20 min to obtain a perovskite layer with a thickness of 500 nm; S24. PMMA-1 and PVA-1 were dissolved in isopropanol at a mass ratio of 1:1 to prepare a solution A with a total concentration of 1 mg / mL. Nano ZnO particles-1 were dispersed in isopropanol and ultrasonically treated to ensure uniform dispersion, preparing a dispersion B with a concentration of 1 mg / mL. Solution A and dispersion B were mixed at a mass ratio of 3:7 and stirred for 30 minutes to promote full integration, resulting in a slurry (PMMA-1:PVA-1:ZnO=1.5:1.5:7). The slurry was annealed at 5000 rpm for 30 seconds at 100°C for 10 minutes to obtain an interface modification layer with a thickness of 10 nm. S25. Preparation of C60 (10 nm) and SnO x (12 nm); S26. An IZO layer (40 nm) is prepared by PVD on the front side of the battery, and an ITO layer (100 nm) is deposited by PVD on the back side (crystalline silicon side). S3. A 180 nm thick Ag grid line is screen-printed on the back of the battery and sintered and cured. A 1 μm thick Ag and a 90 nm thick MgF2 are deposited on the front of the battery using a mask to obtain a perovskite / crystalline silicon heterojunction tandem battery.

[0046] Example 2 This embodiment provides a perovskite / crystalline silicon heterojunction tandem solar cell.

[0047] The difference from Example 1 is that in this example, the concentration of solution A is 2 mg / mL, that is, the mass ratio of PMMA-1:PVA-1:ZnO in the slurry is 3:3:7.

[0048] Example 3 This embodiment provides a perovskite / crystalline silicon heterojunction tandem solar cell.

[0049] The difference from Example 1 is that in this example, the concentration of solution A is 3 mg / mL, that is, the ratio of PMMA-1:PVA-1:ZnO in the slurry is 4.5:4.5:7 (mass ratio).

[0050] Example 4 This embodiment provides a perovskite / crystalline silicon heterojunction tandem solar cell.

[0051] The difference from Example 1 is that in this example, the concentration of dispersion B is 2 mg / mL, that is, the mass ratio of PMMA-1:PVA-1:ZnO in the slurry is 1.5:1.5:14.

[0052] Example 5 This embodiment provides a perovskite / crystalline silicon heterojunction tandem solar cell.

[0053] The difference from Example 1 is that in this example, the concentration of dispersion B is 3 mg / mL, that is, the mass ratio of PMMA-1:PVA-1:ZnO in the slurry is 1.5:1.5:21.

[0054] Example 6 This embodiment provides a perovskite / crystalline silicon heterojunction tandem solar cell.

[0055] The difference from Example 3 is that in this example, solution A and dispersion B are mixed in a mass ratio of 4:6, that is, PMMA-1:PVA-1:ZnO in the slurry = 6:6:6 (mass ratio).

[0056] Example 7 This embodiment provides a perovskite / crystalline silicon heterojunction tandem solar cell.

[0057] The difference from Example 1 is that in this example, the mass ratio of PMMA-1 to PVA-1 in solution A is 3:1.

[0058] Example 8 This embodiment provides a perovskite / crystalline silicon heterojunction tandem solar cell.

[0059] The difference from Example 1 is that in this example, the mass ratio of PMMA-1 to PVA-1 in solution A is 1:3.

[0060] Example 9 This embodiment provides a perovskite / crystalline silicon heterojunction tandem solar cell.

[0061] The difference from Example 1 is that, in this example, the thickness of the interface modification layer is 5 nm by controlling the amount of slurry used in step S24.

[0062] Example 10 This embodiment provides a perovskite / crystalline silicon heterojunction tandem solar cell.

[0063] The difference from Example 1 is that, in this example, the thickness of the interface modification layer is 15 nm by controlling the amount of slurry used in step S24.

[0064] Example 11 This embodiment provides a perovskite / crystalline silicon heterojunction tandem solar cell.

[0065] The difference from Example 1 is that, in this example, the thickness of the interface modification layer is 3 nm by controlling the amount of slurry used in step S24.

[0066] Example 12 This embodiment provides a perovskite / crystalline silicon heterojunction tandem solar cell.

[0067] The difference from Example 1 is that, in this example, the thickness of the interface modification layer is 18 nm by controlling the amount of slurry used in step S24.

[0068] Example 13 This embodiment provides a copper indium gallium selenide (CIGS) perovskite tandem photovoltaic cell, comprising a CIGS multilayer film structure layer, an electron transport layer, a perovskite absorber layer, a hole transport layer, a transparent conductive layer, and a metal wire layer connected sequentially from bottom to top. The fabrication method is as follows: The CIGS battery multilayer film structure consists of a Mo metal back electrode layer (800 nm) physically sputtered onto a glass substrate, followed by a CIGS absorber layer (2 μm) physically vacuum evaporated, and finally a double buffer layer and a second transparent conductive layer fabricated by vacuum physical deposition using a physical vacuum sputtering device. The thickness of the Mo metal back electrode layer is 300 nm, the first buffer layer is a CdS buffer layer (30 nm), and the second buffer layer is a MgZnO buffer layer (30 nm).

[0069] The above describes the preparation of the bottom cell. An IZO layer (10 nm) is deposited on the surface of the N-type hydrogenated amorphous silicon doped layer. The remaining steps are the same as in Example 1. The difference from Example 1 is that the raw materials in the interface modification layer are PMMA-2, PVA-2 and ZnO-2, and the amounts are the same as in Example 1.

[0070] Comparative Example 1 This comparative example provides a perovskite / crystalline silicon heterojunction tandem solar cell.

[0071] The difference from Example 1 is that step S24 is not performed in this comparative example.

[0072] Comparative Example 2 This comparative example provides a perovskite / crystalline silicon heterojunction tandem solar cell.

[0073] The difference from Example 1 is that in this comparative example, the slurry in step S24 only includes PMMA-1 and PVA-1, and the concentration is the same as the total concentration of the slurry in Example 1.

[0074] Comparative Example 3 This comparative example provides a perovskite / crystalline silicon heterojunction tandem solar cell.

[0075] The difference from Example 1 is that, in this comparative example, step S24 is replaced by: preparing a ZnO layer using atomic layer deposition, with the same thickness as in Example 1.

[0076] Performance Test - 1 The performance of the interface modification layer in the perovskite tandem solar cells provided in the examples and comparative examples was tested, and the results are as follows: Table 1 As demonstrated by the embodiments and performance tests, the interface modification layer provided by the present invention has an extremely high absorption rate of ultraviolet light, which can avoid the influence of ultraviolet light on the perovskite layer. At the same time, the absorbed ultraviolet light can be converted into visible light or heat energy, with a conversion rate of over 75% for visible light, thereby improving the light absorption efficiency of the tandem solar cell. In addition, the interface modification layer provided by the present invention has excellent light scattering characteristics, which can redirect some of the incident light to the active layer, thereby further enhancing the light absorption efficiency.

[0077] Performance Test - 2 Performance tests were conducted on the perovskite tandem solar cells provided in the examples and comparative examples under the following conditions: AM1.5, 1000 W / m 2 At 25±2℃, the test results are as follows: Table 2 As can be seen from the embodiments and performance tests, the interface modification layer provided by the present invention can not only improve the UVID resistance of the battery, but also have a positive impact on its photoelectric conversion efficiency.

[0078] As can be seen from the comparison of Examples 1-6, the ratio of the interface modification layer has a significant impact on the ultraviolet light absorption efficiency, the compatibility of other layers, and the overall device performance. First, the ratio of organic materials to ZnO nanoparticles directly determines the ultraviolet light absorption capacity of the interface modification layer. When the copolymer content is high, although the ultraviolet light absorption capacity is enhanced, it may lead to a decrease in the conductivity of the interface modification layer, thereby affecting the charge transport efficiency. When the ZnO nanoparticle content is too high, the uniformity of the film may be reduced due to particle agglomeration, and even interface defects may be caused. Therefore, the present invention preferably uses a mass ratio of organic materials to nano-metal oxide particles of 1:(0.5-1) to ensure that the interface modification layer can guarantee the ultraviolet light absorption performance without negatively affecting other functional layers of the battery.

[0079] A comparison of Examples 9-10 and Examples 11-12 shows that when the thickness of the interface modification layer is within the range defined by the present invention, it can improve the UVID resistance and photoelectric conversion efficiency of the battery.

[0080] A comparison between Example 1 and Comparative Example 1 shows that in Comparative Example 1, the initial PCE without the interface modification layer was 31.35%, while in Example 1, the initial PCE increased to over 32% after the modification layer was introduced. This comparison indicates that the improved battery efficiency is mainly attributed to the passivation effect of the interface modification layer on interface defects and the optimization of electron transport performance. Specifically, the functional groups in the interface modification layer can form chemical bonds with uncoordinated lead ions on the perovskite layer surface through Lewis acid-base interactions, effectively reducing non-radiative recombination losses at the interface. Furthermore, the organic material modification layer doped with ZnO nanoparticles exhibits excellent light scattering properties, redirecting some incident light to the active layer, thereby enhancing light absorption efficiency. Comparison with other data reveals that the short-circuit current density (Jsc) and fill factor (FF) of the interface modification layer sample are both improved, further verifying the improving effect of the interface modification layer on the overall battery performance.

[0081] Meanwhile, a comparison between Example 1 and Comparative Example 1 shows that the present invention, by introducing an interface modification layer, can significantly improve the UVID resistance of the perovskite tandem solar cell. In Comparative Example 1, after 1000 hours of continuous illumination, its photoelectric conversion efficiency (PCE) only maintained about 70% of the original efficiency, while Example 1, by introducing an interface modification layer, showed only less than 10% efficiency decay. This indicates that the modification layer can effectively absorb and convert harmful ultraviolet light, thereby reducing direct damage to the perovskite layer.

[0082] The present invention has been illustrated through the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A perovskite tandem solar cell, characterized in that, The system includes a bottom cell and a top cell disposed on the bottom cell. The top cell comprises, from bottom to top, a hole transport layer, a perovskite layer, an interface modification layer, an electron transport layer, and a top electrode, wherein: The interface modification layer is an organic material-coated nano-metal oxide particle layer. The interface modification layer has an absorption rate of ≥95% for ultraviolet light, a conversion rate of ≥75% for ultraviolet light to visible light, and a haze value of ≥45%.

2. The perovskite tandem solar cell according to claim 1, characterized in that, The light scattering cross-section value of the interface modification layer is ≥1.5×10 -10 cm 2 Preferably 1.5×10 -10 -3×10 -10 cm 2 ; And / or, the effective optical path length extension factor of the interface modification layer is ≥1.15, preferably 1.15-1.80; And / or, the interface modification layer has an absorption rate of 95-99% for ultraviolet light; And / or, the interface modification layer has a conversion rate of 75-90% for ultraviolet light to visible light; And / or, the haze value of the interface modification layer is 45-85%.

3. The perovskite tandem solar cell according to claim 1 or 2, characterized in that, The organic material includes alkenyl polymers, preferably polyacrylic acid materials and / or polyenol materials, and more preferably a combination of polyacrylic acid materials and polyenol materials; Preferably, the mass ratio of the polyacrylic acid material to the polyenol material is 1:(0.3-3).

4. The perovskite tandem solar cell according to any one of claims 1-3, characterized in that, The nano-metal oxide particles include any one or a combination of at least two of nano-zinc oxide, nano-cerium oxide, or nano-iron oxide. Preferably, the particle size D50 of the nano-metal oxide particles is 3-5 nm.

5. The perovskite tandem solar cell according to any one of claims 1-4, characterized in that, The mass ratio of the organic material to the nano-metal oxide particles is 1:(0.5-7), preferably 1:(0.5-1).

6. The perovskite tandem solar cell according to any one of claims 1-5, characterized in that, The thickness of the interface modification layer is 5-15 nm.

7. The perovskite tandem solar cell according to any one of claims 1-6, characterized in that, The electron transport layer is a C60 electron transport layer.

8. A method for preparing a perovskite tandem solar cell as described in any one of claims 1-7, characterized in that, The preparation method includes: S1. Provides a base battery; S2. A hole transport layer, a perovskite layer, an interface modification layer, an electron transport layer, and a top electrode are sequentially fabricated on the bottom cell to obtain the perovskite tandem cell.

9. The preparation method according to claim 8, characterized in that, The method for preparing the interface modification layer includes: preparing a slurry containing organic materials and nano-metal oxide particles, coating, and curing to obtain the interface modification layer.

10. The preparation method according to claim 9, characterized in that, In the slurry, the concentration of the nano-metal oxide particles is 0.5-2.5 mg / mL, preferably 1-2 mg / mL; And / or, the coating method includes spin coating.

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