Perovskite battery assembly and preparation method thereof

Abstract

In order to overcome the problem of ultraviolet-induced stability of the existing perovskite cell, the invention provides a perovskite cell assembly which comprises a transparent conductive layer, an electron transport layer, a perovskite light absorption layer, a hole transport layer and a metal back electrode layer which are stacked in sequence, the perovskite light absorption layer comprises an ABX3 type crystal and a naphthopyran compound coating the surface of the ABX3 type crystal, A is an organic cation, B is a metal ion, and X is a halogen ion. Meanwhile, the invention also discloses a preparation method of the perovskite battery assembly.

Description

Technical Field

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

[0002] Perovskite solar cells, as a new generation of photovoltaic devices, have become a research hotspot and a promising direction for industrialization in the photovoltaic field due to their outstanding advantages such as excellent photoelectric conversion efficiency, low-cost fabrication, and flexible scalability. Perovskite materials (such as formamidinium lead iodide and formamidinium cesium lead iodide perovskite systems) serve as the core active layer of the cell, and their structural stability directly determines the cell's lifespan and the continuity of its photoelectric performance. However, in practical outdoor applications, natural sunlight contains approximately 5%-10% ultraviolet radiation (wavelength 200-400nm). This wavelength of light triggers a series of irreversible degradation reactions in perovskite materials: on the one hand, the high-energy photons of ultraviolet radiation easily break the Pb-I chemical bonds in the perovskite crystal, leading to crystal structure collapse and a surge in defect state density; on the other hand, ultraviolet radiation also accelerates ion migration within the perovskite material (such as I⁻ ion precipitation), forming a surface defect layer and interfacial recombination centers, ultimately causing a rapid decline in the cell's photoelectric conversion efficiency (PCE), severely limiting the commercialization of perovskite solar cells.

[0003] To address the aforementioned UV-induced stability issues, various protective solutions have been proposed in existing technologies. The most direct and widely used solution is to add a UV-protective layer to the light-transmitting side of the perovskite solar cell. The core design principle of this type of UV-protective layer is to absorb or reflect UV radiation by adding UV absorbers or UV shielding agents, thereby reducing UV radiation to the perovskite active layer. However, existing UV-protective layer solutions have significant technical drawbacks, making it difficult to simultaneously improve stability and maintain photoelectric performance. The contradiction between visible light transmittance and UV protection effectiveness: To achieve effective UV blocking efficiency (typically requiring a UV blocking rate ≥90%), existing UV-protective layers need to have a certain thickness (generally ≥50μm) and require the addition of high concentrations of UV-absorbing / shielding components. However, these components exhibit weak absorption or scattering effects on certain visible light bands (especially the blue-violet region, wavelength 400-500nm). Combined with the thickness effect of the UV-protective layer itself, this leads to a decrease in overall visible light transmittance, directly causing a loss in the photoelectric conversion efficiency of perovskite solar cells.

[0004] The long-term stability of the UV-protective layer itself is insufficient: existing UV-protective layers mostly use organic polymers as the matrix (such as polymethyl methacrylate, epoxy resin), or fix the UV-absorbing / shielding components into shape through organic binders. Under long-term outdoor light exposure (especially under the synergistic effect of UV and high temperature), the organic matrix or binder is prone to photo-oxidative degradation, manifested as yellowing and whitening of the material. This not only further reduces visible light transmittance, but may also cause the UV protection performance of the UV-protective layer to fail due to matrix cracking and component migration. In some cases, degradation products may even diffuse to the surface of the perovskite active layer, causing secondary pollution and exacerbating interfacial recombination, ultimately failing to effectively extend the lifespan of the perovskite battery.

[0005] In summary, existing UV protection solutions for perovskite solar cells based on UV-blocking layers suffer from the dual defects of visible light transmittance loss and insufficient long-term stability. These solutions fail to fundamentally address the lifespan and efficiency issues caused by the UV instability of perovskite materials. There is an urgent need to develop a new protection technology that balances high UV blocking efficiency, high visible light transmittance, and long-term structural stability to promote the practical application of perovskite solar cells. Summary of the Invention

[0006] Existing perovskite solar cells suffer from UV-induced stability issues. This invention provides a perovskite solar cell module and its preparation method.

[0007] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: On one hand, the present invention provides a perovskite solar cell module, comprising a transparent conductive layer, an electron transport layer, a perovskite light-absorbing layer, a hole transport layer and a metal back electrode layer stacked sequentially. The perovskite light-absorbing layer comprises an ABX3 type crystal and a naphthopyran compound coated on the surface of the ABX3 type crystal, wherein A is an organic cation, B is a metal ion and X is a halide ion.

[0008] Optionally, the ABX3 type crystals are formed in a stacked grain shape on the surface of the electron transport layer, and the naphthopyran compound is coated on the surface of the ABX3 type crystals and in the gaps between adjacent ABX3 type crystals.

[0009] Optionally, the ABX3 type crystal includes one or more of FACsPbI3, FAPbI3, FACsPbIBr2, FACsPbICl2, CsPbI3, FAMAPbI3, MAPbI3, and MAPbBr3.

[0010] Optionally, the ABX3 type crystal surface has hydroxyl groups, and the naphthopyran compound includes one or more of 6-(4-methoxyphenyl)-8,9-dimethoxy-3,3-diphenyl-3H-naphtho[2,1-b]pyran and 2-(diphenylaminophenyl)-2-phenyl-2H-naphtho[1,2-b]pyran.

[0011] Optionally, the thickness of the perovskite light-absorbing layer is 300~1000nm, and the coating thickness of the naphthopyran compound is 5~20nm.

[0012] Optionally, the transparent conductive layer includes one or more of FTO conductive glass, indium tin oxide conductive glass, indium zinc oxide conductive glass, graphene transparent conductive film, carbon nanotube transparent conductive film, and aluminum zinc oxide conductive glass; and / or, The electron transport layer comprises one or more of SnO2, TiO2, ZnO, ZrO2, methyl [6,6]-phenyl-C61-butyrate, and fullerene; and / or, The hole transport layer comprises one or more of Spiro-OMeTAD, PTAA, PEDOT:PSS, nickel oxide, cuprous iodide, cuprous thiocyanate, PTB7-Th, poly-TPD, and antimony sulfide; and / or, The metal back electrode layer includes one or more of Au, Ag, Al, Cu, Pt, and Ni.

[0013] Optionally, the thickness of the transparent conductive layer is 20~200μm, and / or, The thickness of the electron transport layer is 20~100nm, and / or, The hole transport layer has a thickness of 100~400nm, and / or, The thickness of the metal back electrode layer is 50~2000nm.

[0014] Furthermore, the present invention provides a method for fabricating the perovskite solar cell module as described above, comprising the following steps: An electron transport layer dispersion was dropwise added to the surface of a transparent conductive layer, spin-coated, and then annealed to obtain the electron transport layer. The perovskite precursor solution was dropped onto the surface of the electron transport layer, spin-coated, and an antisolvent was added to induce the crystallization of ABX3 type crystals. After annealing, an ABX3 type crystal layer was formed. A solution of naphthopyran compound was added, spin-coated, annealed, and dried to coat the surface and interstices of the ABX3 type crystal with naphthopyran compound to obtain the perovskite light-absorbing layer. A hole transport layer solution was dropped onto the surface of a perovskite light-absorbing layer, and then spin-coated and dried to obtain a hole transport layer. Metal is deposited on the surface of the hole transport layer to obtain a metal back electrode layer.

[0015] Optionally, after the formation of the ABX3 type crystal layer and before the addition of the naphthopyran compound solution, the following steps are also included: Obtain a mixed solution of oxalic acid and hydrogen peroxide, wherein the molar concentration of oxalic acid is 0.1~1 mol / L and the molar concentration of hydrogen peroxide is 0.05~0.2 mol / L; The mixed solution was dropped onto the surface of the ABX3 crystal layer and spin-coated for 15-30 seconds. The surface of the ABX3 crystal layer was rinsed with anhydrous ethanol and dried with nitrogen to obtain a surface-hydroxylated ABX3 crystal layer.

[0016] Optionally, the spin-coating process of the naphthylpyran compound solution is carried out under negative pressure conditions, with a pressure of 1~20 Pa.

[0017] According to the perovskite solar cell module provided by the present invention, the pyran ring contained in the molecular structure of the naphthopyran compound undergoes a reversible ring-opening isomerization reaction under ultraviolet (200-400 nm) irradiation. This process can efficiently capture the energy of ultraviolet photons and convert it into intramolecular energy, avoiding the direct action of high-energy photons on the Pb-I chemical bonds of the ABX3 type perovskite crystal, thus blocking the triggering path of crystal structure collapse and ion migration from the source. Because the naphthopyran compound has an extremely low molar absorptivity in the visible light band, and the ring-opening isomerization product still retains its original shape... With excellent light transmittance, it does not significantly absorb or scatter visible light (400-800nm), maximizing the absorption capacity of the perovskite light-absorbing layer for visible light. Furthermore, unlike existing independent UV-protective layers, the naphthopyran compound is directly coated onto the ABX3 crystal surface, eliminating the need for additional thickness to the overall module or an additional resin matrix for dispersion. This molecular-level coating effectively reduces the thickness required for effective UV protection, thus avoiding any impact on the photoelectric conversion efficiency of the perovskite solar cell module. Moreover, the naphthopyran compound coating physically blocks external moisture and oxygen from contacting the perovskite crystal, further enhancing stability. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the perovskite battery module provided by the present invention.

[0019] The reference numerals in the accompanying drawings are as follows: 1. Metal back electrode layer; 2. Hole transport layer; 3. Perovskite light-absorbing layer; 31. ABX3 type crystal; 32. Naphthopyran compound; 4. Electron transport layer; 5. Transparent conductive layer. Detailed Implementation

[0020] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0021] See Figure 1 As shown, an embodiment of the present invention provides a perovskite solar cell module, including a transparent conductive layer 5, an electron transport layer 4, a perovskite light-absorbing layer 3, a hole transport layer 2, and a metal back electrode layer 1 stacked sequentially. The perovskite light-absorbing layer 3 includes an ABX3 type crystal 31 and a naphthopyran compound 32 coated on the surface of the ABX3 type crystal 31, wherein A is an organic cation, B is a metal ion, and X is a halide ion.

[0022] In the perovskite light-absorbing layer 3, the pyran ring contained in the molecular structure of the naphthopyran compound 32 undergoes a reversible ring-opening isomerization reaction under ultraviolet (200-400 nm) irradiation. This process can efficiently capture the energy of ultraviolet photons and convert it into intramolecular energy, preventing high-energy photons from directly acting on the Pb-I chemical bonds of the ABX3 type perovskite crystal, thus blocking the triggering path of crystal structure collapse and ion migration from the source. Because the naphthopyran compound 32 has an extremely low molar absorptivity in the visible light band, and the ring-opening isomerization product still maintains good... The light transmittance is excellent, with no significant absorption or scattering of visible light (400-800nm), maximizing the absorption capacity of the perovskite light-absorbing layer 3 for visible light. Furthermore, unlike existing independent UV-protective layers, the naphthopyran compound 32 is directly coated onto the surface of the ABX3 crystal 31, eliminating the need for additional thickness to the overall component and the need for an additional resin matrix for dispersion. This molecular-level coating effectively reduces the thickness required for effective UV protection, thus effectively avoiding any impact on the photoelectric conversion efficiency of the perovskite solar cell module. Moreover, the naphthopyran compound 32 coating layer physically blocks external moisture and oxygen from contacting the perovskite crystal, further enhancing stability.

[0023] In some embodiments, the ABX3 type crystal 31 is formed in a stacked grain shape on the surface of the electron transport layer 4, and the naphthopyran compound 32 is coated on the surface of the ABX3 type crystal 31 and in the gaps between adjacent ABX3 type crystals 31.

[0024] Since the ABX3 type crystal 31 in the perovskite light-absorbing layer 3 is obtained by mixed crystallization of precursors such as metal halide salts and organic cationic halide salts, its surface morphology is an uneven stacked grain state. The intergranular space is the defect concentration area and the main channel for ion migration. Ultraviolet light can easily cause local degradation in this area. The naphthopyran compound 32 is coated on the crystal surface and in the intergranular space, which can form an all-round coating network and effectively suppress the radiation damage of ultraviolet light to the material defect sites between grains.

[0025] In some embodiments, the ABX3 type crystal 31 includes one or more of FACsPbI3, FAPbI3, FACsPbIBr2, FACsPbICl2, CsPbI3, FAMAPbI3, MAPbI3, and MAPbBr3.

[0026] The above ABX3 type crystals are all perovskite systems with excellent photoelectric conversion efficiency. Their intrinsic band gap is adapted to the visible light band and they have high carrier mobility, but they generally suffer from ultraviolet-induced structural instability. The coating of naphthopyran compound 32 does not change the intrinsic electronic structure and photoelectric properties of such crystals. It achieves ultraviolet blocking only through physicochemical action and can complement the performance of high-performance perovskite systems.

[0027] In some embodiments, the ABX3 type crystal 31 has hydroxyl groups on its surface, and the naphthopyran compound 32 includes one or more of 6-(4-methoxyphenyl)-8,9-dimethoxy-3,3-diphenyl-3H-naphtho[2,1-b]pyran and 2-(diphenylaminophenyl)-2-phenyl-2H-naphtho[1,2-b]pyran.

[0028] Because conventional naphthopyran compounds 32 have a weak affinity for ABX3 type crystals, it is difficult to achieve uniform spreading of naphthopyran compounds 32 on the surface and gaps of ABX3 type crystals 31. During the preparation process, droplet shrinkage is prone to occur, leading to local aggregation of naphthopyran compounds 32. This affects their ultraviolet absorption and, on the other hand, the aggregated naphthopyran compounds 32 have a significant absorption effect on visible light, affecting the visible light absorption efficiency of ABX3 type crystals 31. To solve this problem, this invention forms a large number of hydroxyl groups on the surface of ABX3 type crystals 31 through treatment and selects naphthopyran compounds 32 with polar groups. This allows naphthopyran compounds 32 to spread rapidly through hydrogen bonding with ABX3 type crystals 31 during the preparation process, and avoids aggregation of naphthopyran compounds 32 during annealing. This improves the absorption and shielding effect of ultraviolet light while reducing the impact on visible light transmission under the condition of low naphthopyran compound 32 thickness.

[0029] In some embodiments, the thickness of the perovskite light-absorbing layer 3 is 300~1000nm, and the coating thickness of the naphthopyran compound 32 is 5~20nm.

[0030] If the thickness of the perovskite light-absorbing layer 3 is less than 300 nm, the visible light absorption is insufficient, resulting in low photoelectric conversion efficiency. If the thickness of the perovskite light-absorbing layer 3 exceeds 1000 nm, the carrier transport path is too long, the recombination probability increases, and crystal defects are easy to accumulate. This thickness range can balance visible light absorption and carrier transport efficiency, ensuring intrinsic photoelectric performance.

[0031] If the thickness of the naphthopyran compound 32 is less than 5 nm, the coating is incomplete, resulting in a gap in ultraviolet light penetration. If the thickness of the naphthopyran compound 32 exceeds 20 nm, although it can enhance ultraviolet blocking, it may increase the resistance to carrier transport (especially affecting the charge transfer at the interface between the perovskite crystal and the hole transport layer 2). An ultrathin coating layer of 5~20 nm can minimize the impact on carrier migration while ensuring full coverage, and because its thickness is much smaller than that of existing UV protection layers (≥50 μm), it completely avoids the loss of visible light transmittance.

[0032] In some embodiments, the transparent conductive layer 5 comprises one or more of FTO conductive glass, indium tin oxide conductive glass, indium zinc oxide conductive glass, graphene transparent conductive film, carbon nanotube transparent conductive film, and aluminum zinc oxide conductive glass; and / or, The electron transport layer 4 comprises one or more of SnO2, TiO2, ZnO, ZrO2, methyl [6,6]-phenyl-C61-butyrate, and fullerene; and / or, The hole transport layer 2 includes one or more of Spiro-OMeTAD, PTAA, PEDOT:PSS, nickel oxide, cuprous iodide, cuprous thiocyanate, PTB7-Th, poly-TPD, and antimony sulfide; and / or, The metal back electrode layer 1 includes one or more of Au, Ag, Al, Cu, Pt, and Ni.

[0033] In some embodiments, the thickness of the transparent conductive layer 5 is 20~200 μm, and / or, The thickness of the electron transport layer 4 is 20~100nm, and / or, The hole transport layer 2 has a thickness of 100~400nm, and / or, The thickness of the metal back electrode layer 1 is 50~2000nm.

[0034] Another embodiment of the present invention provides a method for fabricating the perovskite solar cell module as described above, comprising the following steps: The electron transport layer 4 dispersion was drop-dropped onto the surface of the transparent conductive layer 5, spin-coated, and then annealed to obtain the electron transport layer 4. The perovskite precursor solution was dropped onto the surface of the electron transport layer 4, spin-coated, and an antisolvent was added to induce the crystallization of ABX3 type crystal 31. After annealing, an ABX3 type crystal layer was formed. A solution of naphthopyran compound was added, spin-coated, and annealed and dried to coat the surface and gaps of ABX3 type crystal 31 with naphthopyran compound 32, thus obtaining the perovskite light-absorbing layer 3. The hole transport layer 2 solution was dropped onto the surface of the perovskite light-absorbing layer 3, and then spin-coated and dried to obtain the hole transport layer 2. Metal is deposited on the surface of hole transport layer 2 to obtain metal back electrode layer 1.

[0035] First, ABX3 type crystal 31 is formed, and then a solution of naphthopyran compound is added and spin-coated. This can avoid the interference between naphthopyran molecules and perovskite precursors during the crystallization stage. The spin-coating method can use centrifugal force to ensure that the naphthopyran compound 32 is uniformly coated on the crystal surface and gaps, forming a continuous and complete protective layer.

[0036] In some embodiments, the spin coating speed of the electron transport layer 4 dispersion is 2000~5000 r / min, the spin coating time is 30~60 s, the annealing temperature is 120~180℃, and the annealing time is 15~30 min. In some embodiments, the concentration of the perovskite precursor solution is 0.8~1.2 mol / L, and its solvent includes one or more of N,N-dimethylformamide, dimethyl sulfoxide, and γ-butyrolactone. The solute can be selected according to the ABX3 type crystal 31 to be formed. Specifically, the solute includes one or more salts of A, B, and X. The spin coating speed is 3000~6000 r / min, and the spin coating time is 20~40 s. In some embodiments, the antisolvent includes one or more of chlorobenzene, toluene, ethyl acetate, and dichloromethane, and the amount of antisolvent added is 0.1 to 0.3 mL per square centimeter of perovskite precursor solution, and the timing of addition is 5 to 15 seconds after the start of spin coating of the perovskite precursor solution. In some embodiments, the annealing temperature of the perovskite precursor solution is 70–150°C, and the annealing time is 10–25 min; the concentration of the naphthopyran compound solution is 0.01–0.05 mol / L, and the solvent includes one or more of dichloromethane, chloroform, and tetrahydrofuran; the spin coating speed is 2000–4000 r / min, and the spin coating time is 25–45 s; the annealing and drying temperature after coating is 60–100°C, and the annealing and drying time is 8–15 min. In some embodiments, the concentration of the hole transport layer 2 solution is 5–20 mg / mL, and the solvent includes one or more of chlorobenzene, toluene, and o-dichlorobenzene; the spin coating speed is 2500–5000 r / min, and the spin coating time is 30–50 s; the drying temperature is 40–80°C, and the drying time is 10–20 min. In some embodiments, the deposition method of the metal back electrode includes one of vacuum thermal evaporation, magnetron sputtering, and electron beam evaporation, with a vacuum level of 1×10⁻⁶ during deposition. -4 ~5×10 -4 Pa, deposition rate is 0.1~1 nm / s.

[0037] In some embodiments, after forming the ABX3 type crystal layer and before adding the naphthopyran compound solution, the following steps are also included: Obtain a mixed solution of oxalic acid and hydrogen peroxide, wherein the molar concentration of oxalic acid is 0.1~1 mol / L and the molar concentration of hydrogen peroxide is 0.05~0.2 mol / L; The mixed solution was dropped onto the surface of the ABX3 crystal layer and spin-coated for 15-30 seconds. The surface of the ABX3 crystal layer was rinsed with anhydrous ethanol and dried with nitrogen to obtain a surface-hydroxylated ABX3 crystal layer.

[0038] Oxalic acid, a weak organic acid, can slightly etch away minute defects (such as amorphous layers or residual impurities) on the surface of ABX3 crystals, exposing the intrinsic surface of the crystal. Hydrogen peroxide, as an oxidant, can oxidize and generate hydroxyl groups (-OH) on the crystal surface, creating hydroxyl-rich active sites. The hydroxyl and amino functional groups in the molecular structure of naphthopyran compound 32 can form hydrogen bonds or coordination bonds with the hydroxyl groups on the crystal surface. This facilitates the rapid and uniform spreading of the naphthopyran compound solution on the surface of ABX3 crystal 31 during spin coating, reduces the spreading thickness of naphthopyran compound 32, effectively solves the visible light scattering problem caused by the aggregation of naphthopyran compound 32, and reduces the impact on photoelectric conversion efficiency.

[0039] In some embodiments, the anhydrous ethanol is rinsed 2 to 3 times, and the amount of anhydrous ethanol used each time is 0.5 to 1 mL per square centimeter of crystal layer surface. The rinsing is done by slow dripping to avoid excessive impact force that could damage the crystal.

[0040] In some embodiments, the spin-coating process of the naphthylpyran compound solution is carried out under negative pressure conditions, with a pressure of 1~20 Pa.

[0041] Under negative pressure, the surface tension of the naphthopyran compound solution decreases, which can quickly remove air bubbles from the naphthopyran compound solution and the gaps between ABX3 crystals. This avoids defects such as pores and pinholes in the coating layer caused by residual air bubbles during spin coating, promotes the spread of the solution on the surface and gaps of ABX3 crystals, and can especially fill tiny gaps, ensuring that the coating layer is free of dead corners and dense and uniform.

[0042] The present invention will be further illustrated by the following examples.

[0043] Example 1 This embodiment illustrates the perovskite solar cell module and its preparation method disclosed in this invention, including the following steps.

[0044] 1. Fabrication of electron transport layer The FTO conductive glass was fixed on the stage of a spin coater, and 200 μL of SnO2 dispersion was dropped onto the surface of the FTO conductive glass with a concentration of 20 wt%. The mixture was spin-coated at 3500 r / min for 45 s. After spin coating, the sample was transferred to a muffle furnace and annealed at 150 °C for 20 min. After natural cooling to room temperature, a SnO2 electron transport layer with a thickness of about 50 nm was obtained.

[0045] 2. Preparation of perovskite light-absorbing layer (1) Formation of ABX3 type crystal layer: 150 μL of FACsPbI3 precursor solution (FAI:CsI:PbI2=0.85:0.15:1) was dropped onto the surface of the electron transport layer and spin-coated at 4500 r / min for 30 s; 10 s after the start of spin-coating, 0.2 mL / cm² of the solution was dropped onto the sample surface. 2 The chlorobenzene anti-solvent induces rapid crystallization; after spin coating, the sample is placed on a hot plate and annealed at 120°C for 15 min to form a FACsPbI3 crystal layer with a thickness of about 600 nm.

[0046] (2) Surface hydroxylation treatment: 100 μL of oxalic acid (0.5 mol / L)-hydrogen peroxide (0.1 mol / L) mixed solution was dropped onto the surface of FACsPbI3 crystal layer and spin-coated at 1500 r / min for 20 s. After spin-coating, the surface was rinsed twice with anhydrous ethanol and then blown with nitrogen gas of 99.99% purity (flow rate 8 L / min) for 4 min to obtain the surface hydroxylated FACsPbI3 crystal layer.

[0047] (3) Coating with naphthopyran compounds: The surface-hydroxylated FACsPbI3 crystal layer was transferred to a negative pressure spin-coating chamber. After closing the chamber door, the vacuum was evacuated to 10 Pa and the negative pressure was maintained for 8 s. 80 μL of naphthopyran compound solution (0.03 mol / L 6-(4-methoxyphenyl)-8,9-dimethoxy-3,3-diphenyl-3H-naphtho[2,1-b]pyran) was dropped onto the surface of the crystal layer and spin-coated at 3500 r / min for 40 s (the negative pressure fluctuation was controlled within ±0.3 Pa during the spin-coating process). After spin-coating, the negative pressure was maintained at 10 Pa for 15 s and then the negative pressure was slowly released. After the sample was taken out, it was pre-dried at room temperature (25% RH) for 2 min and then annealed at 80 °C for 12 min on a hot plate to obtain a perovskite light-absorbing layer with a thickness of about 615 nm (of which the naphthopyran coating layer has a thickness of about 15 nm).

[0048] 3. Preparation of hole transport layer 120 μL of Spiro-OMeTAD solution (Spiro-OMeTAD 10 mg / mL, with 5 mol% LiTFSI and 2 mol% t-BP added as dopants) was dropped onto the surface of the perovskite light-absorbing layer and spin-coated at 3500 r / min for 40 s. After spin-coating, the sample was placed in a glove box (nitrogen atmosphere, oxygen content <0.1 ppm) and dried at 60 °C for 15 min to obtain a Spiro-OMeTAD hole transport layer with a thickness of about 200 nm.

[0049] 4. Fabrication of the metal back electrode layer The sample was transferred to a vacuum thermal evaporation apparatus and evaporated to 3 Pa. Au was deposited on the hole transport layer surface at a deposition rate of 0.5 nm / s, with a deposition thickness of 100 nm, to obtain the metal back electrode layer. After the evaporation was completed, the sample was naturally cooled to room temperature and removed, thus completing the fabrication of the perovskite solar cell module.

[0050] Example 2 This embodiment illustrates the perovskite solar cell module and its preparation method disclosed in this invention, including most of the operational steps in Example 1, with the following differences: In step 2, without surface hydroxylation treatment, the surface of the un-hydroxylated FACsPbI3 crystal layer is directly coated with naphthopyran compounds.

[0051] Example 3 This embodiment illustrates the perovskite solar cell module and its preparation method disclosed in this invention, including most of the operational steps in Example 1, with the following differences: In step 2, the spin coating and annealing drying of the naphthopyran compounds are carried out at atmospheric pressure.

[0052] Comparative Example 1 This comparative example is used to illustrate the perovskite solar cell module and its preparation method disclosed in this invention, including most of the operational steps in Example 1, with the following differences: In step 2, the coating operation of naphthopyran compounds is not performed.

[0053] Comparative Example 2 This comparative example is used to illustrate the perovskite solar cell module and its preparation method disclosed in this invention, including most of the operational steps in Example 1, with the following differences: In step 2, the coating operation of naphthopyran compounds is not performed.

[0054] After step 4, a film containing 6-(4-methoxyphenyl)-8,9-dimethoxy-3,3-diphenyl-3H-naphtho[2,1-b]pyran is attached to the exposed surface of the FTO conductive glass.

[0055] Performance testing The perovskite solar cell modules prepared above were subjected to the following performance tests: 1. Initial photoelectric conversion efficiency (PCE) test An AM1.5G standard solar simulator conforming to IEC60904-9 (irradiance 100mW / cm², 25℃) was used; the current-voltage (IV) curve of the component was tested using a Keithley 2400 source meter, and the short-circuit current density (Jsc), open-circuit voltage (Voc), and fill factor (FF) were read; the photoelectric conversion efficiency was calculated according to the formula PCE=(Jsc×Voc×FF) / irradiance, and three parallel samples were tested for each group, and the average value was taken.

[0056] 2. UV stability test A xenon lamp aging test chamber was used, equipped with a 200-400nm ultraviolet filter (to block visible light), with an irradiation intensity of 100mW / cm². 2 Temperature control: 30±2℃, humidity control: 50±5%RH; After 1000 hours of aging, the components were removed and tested for UV aging photoelectric conversion efficiency (PCE) (using the same method as test 1), and the photoelectric conversion efficiency decay rate was calculated.

[0057] Observe the surface of the aged perovskite solar cell module to see if there are any problems such as yellowing or whitening that affect the transmittance of visible light.

[0058] The test results are entered into Table 1.

[0059] Table 1

[0060] As can be seen from the test results of Example 1 and Comparative Example 1, the coating treatment of naphthopyran compounds in the perovskite light-absorbing layer can significantly improve the ultraviolet stability of the perovskite solar cell module, effectively suppress the decay of photoelectric conversion efficiency under ultraviolet irradiation, and will not have a significant negative impact on the initial photoelectric conversion efficiency of the module.

[0061] The test results of Examples 1 and 2 show that surface hydroxylation treatment of ABX3 crystals helps to optimize the coating effect of naphthopyran compounds on the crystal surface and gaps, reduce their aggregation, and thus improve the ultraviolet stability of the module. At the same time, it can also avoid the influence on visible light transmission and better preserve the initial photoelectric conversion efficiency of the module.

[0062] The test results of Examples 1 and 3 show that spin coating of naphthopyran compound solutions under negative pressure can avoid defects in the protective layer and visible light blocking caused by residual bubbles during the coating process, forming a more complete and dense coating network, thereby further enhancing the component's ability to protect against ultraviolet rays and improving its stability.

[0063] As can be seen from the test results of Example 1 and Comparative Example 2, the built-in protection method of directly coating the surface of the ABX3 crystal with naphthopyran compounds is better able to balance the initial photoelectric conversion efficiency and long-term stability of the module compared with the external protection method of attaching a film containing the compound to the outside of the transparent conductive layer. It can also avoid the whitening and other aging phenomena of the external film during the ultraviolet aging process, thus ensuring the long-term stability of the light transmittance of the module.

[0064] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A perovskite solar cell module, characterized in that, It includes a transparent conductive layer, an electron transport layer, a perovskite light-absorbing layer, a hole transport layer, and a metal back electrode layer stacked in sequence. The perovskite light-absorbing layer includes an ABX3 type crystal and a naphthopyran compound coated on the surface of the ABX3 type crystal, wherein A is an organic cation, B is a metal ion, and X is a halide ion.

2. The perovskite solar cell module according to claim 1, characterized in that, The ABX3 type crystals are formed in a stacked grain shape on the surface of the electron transport layer, and the naphthopyran compounds are coated on the surface of the ABX3 type crystals and in the gaps between adjacent ABX3 type crystals.

3. The perovskite solar cell module according to claim 1, characterized in that, The ABX3 type crystal includes one or more of FACsPbI3, FAPbI3, FACsPbIBr2, FACsPbICl2, CsPbI3, FAMAPbI3, MAPbI3, and MAPbBr3.

4. The perovskite solar cell module according to claim 1, characterized in that, The ABX3 type crystal has hydroxyl groups on its surface, and the naphthopyran compounds include one or more of 6-(4-methoxyphenyl)-8,9-dimethoxy-3,3-diphenyl-3H-naphtho[2,1-b]pyran and 2-(diphenylaminophenyl)-2-phenyl-2H-naphtho[1,2-b]pyran.

5. The perovskite solar cell module according to claim 1, characterized in that, The thickness of the perovskite light-absorbing layer is 300~1000nm, and the coating thickness of the naphthopyran compound is 5~20nm.

6. The perovskite solar cell module according to claim 1, characterized in that, The transparent conductive layer includes one or more of the following: FTO conductive glass, indium tin oxide conductive glass, indium zinc oxide conductive glass, graphene transparent conductive film, carbon nanotube transparent conductive film, and aluminum zinc oxide conductive glass; and / or, The electron transport layer comprises one or more of SnO2, TiO2, ZnO, ZrO2, methyl [6,6]-phenyl-C61-butyrate, and fullerene; and / or, The hole transport layer comprises one or more of Spiro-OMeTAD, PTAA, PEDOT:PSS, nickel oxide, cuprous iodide, cuprous thiocyanate, PTB7-Th, poly-TPD, and antimony sulfide; and / or, The metal back electrode layer includes one or more of Au, Ag, Al, Cu, Pt, and Ni.

7. The perovskite solar cell module according to claim 1, characterized in that, The thickness of the transparent conductive layer is 20~200μm, and / or, The thickness of the electron transport layer is 20~100nm, and / or, The hole transport layer has a thickness of 100~400nm, and / or, The thickness of the metal back electrode layer is 50~2000nm.

8. The method for preparing a perovskite solar cell module according to any one of claims 1 to 7, characterized in that, The following steps are included: An electron transport layer dispersion was dropwise added to the surface of a transparent conductive layer, spin-coated, and then annealed to obtain the electron transport layer. The perovskite precursor solution was dropped onto the surface of the electron transport layer, spin-coated, and an antisolvent was added to induce the crystallization of ABX3 type crystals. After annealing, an ABX3 type crystal layer was formed. A solution of naphthopyran compound was added, spin-coated, annealed, and dried to coat the surface and interstices of the ABX3 type crystal with naphthopyran compound to obtain the perovskite light-absorbing layer. A hole transport layer solution was dropped onto the surface of a perovskite light-absorbing layer, and then spin-coated and dried to obtain a hole transport layer. Metal is deposited on the surface of the hole transport layer to obtain a metal back electrode layer.

9. The method for preparing a perovskite solar cell module according to claim 8, characterized in that, After the formation of the ABX3 type crystal layer and before the addition of the naphthopyran compound solution, the following steps are also included: Obtain a mixed solution of oxalic acid and hydrogen peroxide, wherein the molar concentration of oxalic acid is 0.1~1 mol / L and the molar concentration of hydrogen peroxide is 0.05~0.2 mol / L; The mixed solution was dropped onto the surface of the ABX3 crystal layer and spin-coated for 15-30 seconds. The surface of the ABX3 crystal layer was rinsed with anhydrous ethanol and dried with nitrogen to obtain a surface-hydroxylated ABX3 crystal layer.

10. The method for preparing a perovskite solar cell module according to claim 8, characterized in that, The spin-coating process of the naphthopyran compound solution was carried out under negative pressure conditions, with a pressure of 1~20 Pa.

Images