Perovskite solar cell based on halogen-containing substituted aromatic amine organic ammonium salt additive

Abstract

This invention discloses an inverted perovskite solar cell based on a halogen-substituted aromatic amine organic ammonium salt additive, a perovskite light-absorbing layer, and the field of perovskite solar cell technology. This invention introduces an organic ammonium salt additive containing halogen substituents and ammonium salt groups into the perovskite precursor solution. Utilizing the multi-site interactions formed between the additive's functional groups and the perovskite precursor components, it achieves synergistic regulation of interfacial defect states and residual stress in the thin film, thereby obtaining a perovskite thin film with high crystallinity, low defect density, and high stability. The inverted perovskite solar cell device prepared using this method exhibits superior interfacial charge transport capability and lower non-radiative recombination loss, significantly improving device performance. Furthermore, the device prepared by this invention demonstrates excellent operational stability under long-term illumination and thermal aging conditions, showing promising application prospects.

Description

Technical Field

[0001] This invention belongs to the field of perovskite solar cell technology, and relates to perovskite light-absorbing layers and inverted perovskite solar cells based on halogen-substituted aromatic amine organic ammonium salt additives. Background Technology

[0002] In recent years, perovskite solar cells (PSCs) have become an important research direction in next-generation photovoltaic technology due to their advantages such as high photoelectric conversion efficiency, low-cost solution processing, and flexible fabrication. Currently, the certified photoelectric conversion efficiency of single-junction perovskite solar cells is approaching the theoretical limit, demonstrating broad prospects for industrial application. Among them, inverted perovskite solar cells have attracted widespread attention due to their advantages such as low hysteresis, excellent stability, and suitability for tandem devices.

[0003] The crystal quality and defect state of the perovskite thin film itself are key factors limiting further performance improvements in devices. During the formation of perovskite thin films, uncoordinated defects, halogen vacancies, and ion migration channels easily form within the perovskite crystal, leading to severe nonradiative recombination losses and reducing the device's open-circuit voltage and fill factor. Furthermore, residual lattice strain is generated during the annealing and crystallization process of perovskite thin films, further inducing phase separation and interface degradation, severely impacting the long-term operational stability of the device.

[0004] Introducing functionalized additives into perovskite precursor solutions is a simple and effective method for control. Through the interaction between the additives and the perovskite precursor, crystal nucleation and growth processes can be modulated, thereby optimizing thin film crystallization behavior and reducing defect density. However, additives typically possess only a single function, such as improving crystal quality or only achieving surface defect passivation, making it difficult to simultaneously address defect suppression and lattice strain release. Therefore, developing a multifunctional additive with both defect passivation and strain regulation functions is crucial for achieving high-efficiency and high-stability inverted perovskite solar cells. Organic ammonium salt molecules containing halogen substituents and ammonium salt groups can not only interact with uncoordinated Pb through the ammonium salt groups... 2+ By forming coordination interactions and achieving defect passivation, halogen substituents can also be used to regulate perovskite crystallization and local electronic structure, thereby improving the crystallinity of thin films and alleviating residual strain. Therefore, introducing such functionalized organic ammonium salt additives into perovskite precursor solutions is expected to achieve synergistic regulation of perovskite defects and lattice strain, further enhancing the photoelectric performance and long-term operational stability of inverted perovskite solar cells. Summary of the Invention

[0005] One objective of this invention is to provide a method for synergistically regulating perovskite crystallization, defects, and lattice strain based on halogen-substituted aromatic amine organic ammonium salt additives. A second objective of this invention is to provide an inverted perovskite solar cell.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] Based on halogen-substituted aromatic amine organic ammonium salt additives, the additives are aromatic molecules containing halogen substituents and ammonium salt groups; the aromatic molecules containing halogen substituents and ammonium salt groups are 4-fluorobenzylamine hydrobromide, difluorobenzylamine hydrobromide, trifluoromethylbenzylamine hydrobromide, p-fluoroaniline hydrobromide, p-chloroaniline hydroiodide, or p-bromoaniline hydrobromide.

[0008] The additive possesses both defect passivation and strain regulation functions. Organic ammonium salt molecules containing halogen substituents and ammonium salt groups interact with uncoordinated Pb in the perovskite film through these ammonium salt groups. 2+ Sn 2+ Or Ge 2+ Coordination is formed, and halogen substituents are used to regulate the crystallization and local electronic structure of perovskite, thereby improving the crystal quality of perovskite films and alleviating residual strain.

[0009] A perovskite light-absorbing layer, wherein the material of the perovskite light-absorbing layer is ABX3, where A is CH3NH3. + (MA) + CH(NH2)2 + (FA) + ), Cs + or Rb + One or more of them, B is Pb 2+ Sn 2+ Or Ge 2+ One or more of them, X is Cl - ,Br - Or I - One or more of them;

[0010] During the preparation of the perovskite light-absorbing layer, the additive is directly added to the precursor solution. The functional groups in the additive passivate perovskite defects and alleviate lattice strain through their interaction with A, B, and X.

[0011] The surface of the perovskite light-absorbing layer is more dense and uniform, with a significantly increased grain size of 300-400 nm; the root mean square roughness of the perovskite light-absorbing layer is reduced to 13.8 nm; the residual tensile strength of the perovskite light-absorbing layer is significantly reduced; the perovskite light-absorbing layer has a higher fluorescence emission intensity and an increased average carrier lifetime of over 691.90 ns.

[0012] A method for preparing a perovskite light-absorbing layer includes the following steps:

[0013] (1) Dissolve the perovskite precursor material in an organic solvent to form a perovskite precursor solution;

[0014] (2) Add halogen-substituted aromatic amine organic ammonium salt additives to the perovskite precursor solution to form a modified precursor solution;

[0015] (3) The modified precursor solution is spin-coated onto the surface of the modified layer on the hole transport layer, and anti-solvent treatment and thermal annealing are performed to form a perovskite film that takes into account both defect passivation and strain release.

[0016] In the above method, in step (1), the concentration of the perovskite light-absorbing layer material in the perovskite precursor solution is 1.2~1.8 mol / L, and the solvent is one or more of N,N-dimethylformamide (DMF) or dimethyl sulfoxide (DMSO).

[0017] In the above method, in step (2), the concentration of the halogen-substituted aromatic amine organic ammonium salt additive is 5 × 10⁻⁶. -3 ~7×10 -3 mmol / mL.

[0018] An inverted perovskite solar cell is disclosed, wherein the inverted perovskite solar cell employs the aforementioned perovskite light-absorbing layer. The inverted perovskite solar cell comprises, from bottom to top, a transparent conductive substrate, a hole transport layer, a modification layer, a perovskite light-absorbing layer, an electron transport layer, and a metal electrode; the photoelectric conversion efficiency of the inverted perovskite solar cell is above 25.70%; and it retains 85.71% of its initial efficiency after 850 hours of continuous light aging.

[0019] A method for fabricating an inverted perovskite solar cell, the method comprising the following steps:

[0020] (1) Disperse the hole transport layer material in isopropanol or deionized water, and then spin coat it onto the surface of the pretreated transparent conductive substrate at a speed of 3000~4000 rpm. After spin coating for 20~40 s, anneal at 100~150℃ for 10~30 min to form a hole transport layer on the surface of the transparent conductive substrate.

[0021] (2) After diluting the oxide nanoscale dispersion, spin-coat it onto the hole transport layer at a speed of 2000~3000 rpm. After spin-coating for 30~40 s, anneal at 100~150℃ for 10~30 min, and then anneal at 100~120℃ for 10~30 min to form a modification layer on the surface of the hole transport layer.

[0022] (3) Add the halogen-substituted aromatic amine organic ammonium salt additive to the perovskite precursor solution containing the perovskite light-absorbing layer, and drop it onto the surface of the modified layer. First spin coat at a speed of 1000~2000 rpm for 5~10 s, then spin coat at a speed of 3000~5000 rpm for 40~50 s. Add the antisolvent in the last 5~10 s of the spin coating, and then anneal at 100~120℃ for 20~30 min to prepare the perovskite light-absorbing layer film.

[0023] (4) In 10 -5 Under high vacuum conditions of Pa, organic C with a thickness of 18~25 nm was deposited on the surface of the perovskite film by thermal evaporation. 60 , as an electron transport layer;

[0024] (5) By depositing a metal electrode material with a thickness of 80~150 nm on the electron transport layer, an inverted perovskite solar cell can be prepared.

[0025] In the above method, the transparent conductive substrate is made of either ITO or FTO.

[0026] In the above method, in step (1), the material of the hole transport layer is ((4-(7H-dibenzo[c,g]carbazol-7-yl)butyl)phosphonic acid (CbzNaph), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], poly(3-hexylthiophene-2,5-diyl), (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid (Me-4PACz) or NiO. x Any one or more of the following; the material concentration of the hole transport layer is 0.5~30 mg / mL.

[0027] In the above method, in step (2), the oxide is aluminum oxide, silicon oxide or magnesium oxide.

[0028] In the above method, in step (3), the antisolvent is chlorobenzene (CB), ethyl acetate (EA), toluene, diethyl ether, or anisole.

[0029] In the above method, in step (5), the metal electrode material is any one of Au, Ag or Cu.

[0030] The beneficial effects of this invention are as follows:

[0031] 1. This invention discloses a method for synergistically regulating the crystallization kinetics, defect states, and lattice strain of perovskite based on multifunctional organic molecules. By introducing organic functional molecules with polar functional groups and multi-site interaction capabilities into the perovskite precursor solution, these functional molecules can form coordination interactions and hydrogen bond networks with metal ions, organic cations, and halide ions in the perovskite, thereby effectively regulating the local coordination environment in the precursor solution, promoting uniform grain growth and preferred crystal plane orientation, and improving the crystallinity and morphological uniformity of the perovskite film. Furthermore, the functional molecules in this invention can effectively reduce uncoordinated defects and grain boundary defects in the perovskite film, while alleviating the residual tensile strain formed during crystallization, which is beneficial for forming a denser, flatter perovskite film with lower defect density, thereby improving carrier lifetime and charge transport efficiency. In addition, this regulation strategy can optimize the interfacial contact and energy level matching between the perovskite layer and the carrier transport layer, promote the extraction and transport of photogenerated carriers, and reduce charge recombination at the interface.

[0032] 2. This invention also discloses a perovskite solar cell, wherein the device uses a high-quality perovskite thin film prepared by the above-described synergistic control method as the light-absorbing layer in the solar cell. Furthermore, the perovskite thin film modified with additives exhibits higher crystallinity, larger grain size, lower defect density, and a superior interfacial energy level structure, which helps to improve the open-circuit voltage, fill factor, and carrier extraction efficiency of the device. Simultaneously, the reduced lattice strain and ion migration behavior significantly improve the device's operational stability. Experimental results show that the perovskite solar cell prepared by this invention can achieve high photoelectric conversion efficiency and maintains a high initial efficiency retention rate even after long-term maximum power point tracking tests. Attached Figure Description

[0033] Figure 1 The X-ray photoelectron spectra of the perovskite light-absorbing layers in Example 1 and Comparative Example 1 are shown.

[0034] Figure 2 The X-ray diffraction patterns of the perovskite light-absorbing layers in Example 1 and Comparative Example 1 are shown below.

[0035] Figure 3 These are scanning electron microscope images of the perovskite film surfaces formed in Example 1 and Comparative Example 1;

[0036] Figure 4 Atomic force microscope images and surface roughness curves corresponding to the perovskite light-absorbing layers formed in Example 1 and Comparative Example 1;

[0037] Figure 5 The results of grazing incidence X-ray diffraction strain analysis are shown for the perovskite light-absorbing layers formed in Example 1 and Comparative Example 1.

[0038] Figure 6 The steady-state fluorescence spectra are those corresponding to the perovskite light-absorbing layers formed in Example 1 and Comparative Example 1.

[0039] Figure 7 The time-resolved fluorescence spectra are those corresponding to the perovskite light-absorbing layers formed in Example 1 and Comparative Example 1.

[0040] Figure 8 Energy level diagrams of the perovskite light-absorbing layer, hole transport layer, and electron transport layer formed in Example 1 and Comparative Example 1;

[0041] Figure 9 Current density-voltage curves obtained by reverse scanning of the perovskite solar cells prepared in Example 1 and Comparative Example 1 in their fresh state;

[0042] Figure 10 The results show the stability test results of the unencapsulated perovskite solar cells prepared in Example 1 and Comparative Example 1 under continuous maximum power point tracking conditions. Detailed Implementation

[0043] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto. For process parameters not specifically noted, conventional techniques can be referred to.

[0044] Example 1

[0045] An inverted perovskite solar cell comprises, from bottom to top, an ITO transparent conductive substrate, a CbzNaph hole transport layer, an alumina modification layer, a perovskite light-absorbing layer, an electron transport layer, and a metal electrode. The perovskite light-absorbing layer is synergistically regulated by functional organic molecules to achieve optimized crystallization kinetics, defect passivation, and lattice strain release. The specific fabrication method is as follows:

[0046] (1) The ITO transparent conductive substrate was ultrasonically cleaned with detergent, deionized water and isopropanol in sequence, dried under nitrogen, and then treated with ultraviolet ozone for 15 min to obtain the pretreated ITO transparent conductive substrate, which was then cooled for later use.

[0047] (2) Dissolve ((4-(7H-dibenzo[c,g]carbazol-7-yl)butyl)phosphonic acid (CbzNaph) hole transport material in isopropanol solvent to prepare a CbzNaph solution with a concentration of 1.5 mg / mL. Add 30 μL of the solution to the surface of the ITO transparent conductive substrate pretreated in step (1), spin coat at 3000 rpm for 30 s, and then anneal at 100℃ for 10 min to form a CbzNaph hole transport layer on the surface of the ITO transparent conductive substrate.

[0048] (3) After diluting the alumina nano-scale dispersion, spin-coat it onto the hole transport layer at a speed of 2000 rpm. After spin-coating for 30 s, anneal at 100 ℃ for 15 min, and then anneal at 100 ℃ for 10~30 min to form a modification layer on the surface of the hole transport layer.

[0049] (4) Cs 0.05 FA 0.95 A modified perovskite precursor solution was formed by mixing a PbI3 perovskite precursor solution with the additive 4-fluorobenzylamine hydrobromide (pF-PMABr) (CAS No.: 2270172-94-4), with a pF-PMABr concentration of 6 × 10⁻⁶. -3 mmol / mL. Then, 40 μL of modified perovskite precursor solution was dropped onto the surface of the modified layer in step (3). First, it was spin-coated at 1000 rpm for 10 s, then at 4000 rpm for 50 s. 5 s before the end of the spin coating, 170 μL of anti-solvent chlorobenzene was dropped. Then, it was annealed at 100 ℃ for 30 min to form a high-quality perovskite light-absorbing layer on the surface of the modified layer.

[0050] (5) In 10 -5 Under high vacuum conditions of Pa, organic C with a thickness of 20 nm was deposited on the surface of the electron transport layer thin film by thermal evaporation. 60 , as an electron transport layer;

[0051] (6) In 10 -5 An inverted perovskite solar cell can be fabricated by depositing a 100 nm thick Cu metal electrode on the surface of the electron transport layer thin film under high vacuum conditions of Pa through thermal evaporation.

[0052] Example 2

[0053] An inverted perovskite solar cell comprises, from bottom to top, an FTO transparent conductive substrate, a Me-4PACz hole transport layer, an alumina modification layer, a perovskite light-absorbing layer, an electron transport layer, and a metal electrode. The perovskite light-absorbing layer is synergistically regulated by functional organic molecules to achieve optimized crystallization kinetics, defect passivation, and lattice strain release. The specific fabrication method is as follows:

[0054] (1) The ITO transparent conductive substrate was ultrasonically cleaned with detergent, deionized water and isopropanol in sequence, dried under nitrogen, and treated with ultraviolet ozone for 15 min to obtain the pretreated ITO transparent conductive substrate, which was then cooled for later use.

[0055] (2) Dissolve (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid (Me-4PACz) hole transport material in isopropanol solvent to prepare a Me-4PACz solution with a concentration of 0.5 mg / mL. Add 30 μL of the solution to the surface of the ITO transparent conductive substrate pretreated in step (1), spin coat at 3000 rpm for 30 s, and then anneal at 100 ℃ for 10 min to form a Me-4PACz hole transport layer on the surface of the ITO transparent conductive substrate.

[0056] (3) After diluting the alumina nano-scale dispersion, spin-coat it onto the hole transport layer at a speed of 2000 rpm. After spin-coating for 30 s, anneal at 100 ℃ for 15 min, and then anneal at 100 ℃ for 10 min to form a modification layer on the surface of the hole transport layer.

[0057] (4) Cs 0.05 FA 0.95 A modified perovskite precursor solution is formed by mixing a PbI3 perovskite precursor solution with an additive pF-PMABr, wherein the concentration of pF-PMABr is 6 × 10⁻⁶. -3 mmol / mL. Then, 40 μL of modified perovskite precursor solution was dropped onto the surface of the modified layer in step (3). First, it was spin-coated at 1000 rpm for 10 s, then at 4000 rpm for 50 s. 170 μL of antisolvent was dropped 5 s before the end of spin-coating. Then, it was annealed at 100℃ for 30 min to form a high-quality perovskite light-absorbing layer on the surface of the modified layer.

[0058] (5) In 10 -5 Under high vacuum conditions of Pa, organic C with a thickness of 20 nm was deposited on the surface of the electron transport layer thin film by thermal evaporation. 60 , as an electron transport layer;

[0059] (6) In 10 -5 An inverted perovskite solar cell can be fabricated by depositing a 100 nm thick Ag metal electrode on the surface of the electron transport layer thin film under high vacuum conditions (Pa).

[0060] Example 3

[0061] An inverted perovskite solar cell comprises, from bottom to top, an ITO transparent conductive substrate, a CbzNaph hole transport layer, a silicon oxide modification layer, a perovskite light-absorbing layer, an electron transport layer, and a metal electrode. The perovskite light-absorbing layer is synergistically regulated by functional organic molecules to achieve optimized crystallization kinetics, defect passivation, and lattice strain release. The specific fabrication method is as follows:

[0062] (1) The ITO transparent conductive substrate was ultrasonically cleaned with detergent, deionized water and isopropanol in sequence, dried under nitrogen, and treated with ultraviolet ozone for 15 min to obtain the pretreated ITO transparent conductive substrate, which was then cooled for later use.

[0063] (2) Dissolve ((4-(7H-dibenzo[c,g]carbazol-7-yl)butyl)phosphonic acid (CbzNaph) hole transport material in isopropanol solvent to prepare a CbzNaph solution with a concentration of 1.5 mg / mL. Add 30 μL of the solution to the surface of the ITO transparent conductive substrate pretreated in step (1), spin coat at 3000 rpm for 30 s, and then anneal at 100 ℃ for 10 min to form a CbzNaph hole transport layer on the surface of the ITO transparent conductive substrate.

[0064] (3) After diluting the silica nanoscale dispersion, spin-coat it onto the hole transport layer at a speed of 3000 rpm. After spin-coating for 40 s, anneal at 100 ℃ for 10 min, and then anneal at 100~120 ℃ for 10~30 min to form a modification layer on the surface of the hole transport layer.

[0065] (4) Cs 0.05 FA 0.95 A modified perovskite precursor solution is formed by mixing a PbI3 perovskite precursor solution with an additive pF-PMABr, wherein the concentration of pF-PMABr is 6 × 10⁻⁶. -3 mmol / mL. Then, 40 μL of modified perovskite precursor solution was added to the surface of the modified layer in step (3). First, it was spin-coated at 1000 rpm for 10 s, then at 4000 rpm for 50 s. 5 s before the end of the spin coating, 170 μL of antisolvent ethyl acetate was added. Then, it was annealed at 100℃ for 30 min to form a high-quality perovskite light-absorbing layer on the surface of the modified layer.

[0066] (5) In 10 -5 Under high vacuum conditions of Pa, organic C with a thickness of 20 nm was deposited on the surface of the electron transport layer thin film by thermal evaporation. 60 , as an electron transport layer;

[0067] (6) In 10 -5 An inverted perovskite solar cell can be fabricated by depositing a 100 nm thick Ag metal electrode on the surface of the electron transport layer thin film under high vacuum conditions (Pa).

[0068] Comparative Example 1

[0069] An inverted perovskite solar cell, the preparation method of which differs from that of Example 1, is as follows: In step (4) of Example 1, "Cs..." 0.05 FA 0.95 A modified perovskite precursor solution is formed by mixing a PbI3 perovskite precursor solution with an additive pF-PMABr, wherein the concentration of pF-PMABr is 5 × 10⁻⁶. -3 mmol / mL. Then, 40 μL of modified perovskite precursor solution was added dropwise to the surface of the alumina-modified layer in step (3), and spin-coated at 4000 rpm for 30 s. 5 s before the end of spin-coating, 170 μL of antisolvent was added dropwise, followed by annealing at 100℃ for 30 min to form a high-quality perovskite light-absorbing layer on the surface of the CbzNaph hole transport layer;” was modified to “take 40 μL of Cs 0.05 FA 0.95 The PbI3 perovskite precursor solution was dropped onto the surface of the modified layer in step (3). First, it was spin-coated at 1000 rpm for 10 s, then at 4000 rpm for 50 s. 170 μL of antisolvent was dropped 5 s before the end of spin-coating. Then, it was annealed at 100 °C for 30 min to form a high-quality perovskite light-absorbing layer on the surface of the modified layer. The remaining steps were the same as in the example, and an inverted perovskite solar cell was prepared.

[0070] Performance testing

[0071] 1. The perovskite light-absorbing layers formed in Example 1 and Comparative Example 1 were subjected to X-ray diffraction, scanning electron microscopy, atomic force microscopy, and grazing incidence X-ray diffraction strain analysis, respectively.

[0072] Figure 1 The X-ray photoelectron spectra corresponding to the perovskite light-absorbing layers formed in Example 1 and Comparative Example 1 are shown. The shift of the spectral lines illustrates the interaction between the additive and the metal ions in the perovskite and the defect passivation effect.

[0073] Figure 2 X-ray diffraction tests were performed on the perovskite light-absorbing layers formed in Example 1 and Comparative Example 1. Compared with Comparative Example 1, the (100) peak of Example 1 was significantly higher, indicating that the additives optimized the crystallinity of the perovskite film and improved the crystal quality.

[0074] Figure 3 These are scanning electron microscope images of the perovskite light-absorbing layer surfaces formed in Example 1 and Comparative Example 1. Figure 5 As can be seen, the perovskite film surface in Example 1 is more dense and uniform, and the grain size is significantly increased. This indicates that the introduction of additives helps improve the surface morphology of the perovskite film and reduce grain boundary defects.

[0075] Figure 4 Atomic force microscopy images and surface roughness curves corresponding to the perovskite light-absorbing layers formed in Example 1 and Comparative Example 1. From Figure 7 As can be seen from the results, the root mean square roughness of the perovskite film in Example 1 is significantly reduced, indicating that the additive can effectively inhibit local rapid crystallization, thereby obtaining a smoother and more uniform film surface, which is beneficial to the uniform deposition of subsequent functional layers and interface contact.

[0076] Figure 5 The results are from grazing incidence X-ray diffraction strain analysis of the perovskite absorbing layers formed in Example 1 and Comparative Example 1. Figure 9 As can be seen, compared with Comparative Example 1, the residual tensile strain of the perovskite film in Example 1 is significantly reduced, indicating that the additive can effectively alleviate the internal lattice distortion and residual stress generated during the rapid crystallization of perovskite, thereby improving the stability of the crystal structure.

[0077] 2. The energy level structure and carrier dynamics of the perovskite light-absorbing layers formed in Example 1 and Comparative Example 1 were tested respectively.

[0078] Figure 6 The steady-state fluorescence spectrum and time-resolved fluorescence spectrum are shown for the perovskite absorbing layers formed in Example 1 and Comparative Example 1. Compared to Comparative Example 1, the perovskite film in Example 1 has a higher fluorescence emission intensity, indicating that the introduction of additives effectively reduces the defect density in the perovskite film.

[0079] from Figure 7 The time-resolved fluorescence spectra of the perovskite absorber layers formed in Example 1 and Comparative Example 1 are shown. Compared to Comparative Example 1, the perovskite film in Example 1 exhibits higher fluorescence emission intensity and a longer carrier lifetime, indicating that the introduction of the additive effectively suppresses the nonradiative recombination process, resulting in a correspondingly shorter average carrier lifetime (…). The calculation parameters are shown in Table 1.

[0080]

[0081] Figure 8 This is an energy level diagram of the perovskite light-absorbing layer and electron transport layer formed in Example 1 and Comparative Example 1. From... Figure 10 As can be seen from the example, the perovskite light-absorbing layer and the carrier transport layer in Example 1 have a more reasonable energy level match, which is beneficial to the extraction and transport of photogenerated carriers, while reducing non-radiative recombination losses at the interface.

[0082] 3. The device performance and stability of the perovskite solar cells prepared in Example 1 and Comparative Example 1 were tested.

[0083] Figure 9The current density-voltage curves obtained by reverse scanning of the perovskite solar cells prepared in Example 1 and Comparative Example 1 are shown in Table 2. The corresponding curves are compiled into a photovoltaic performance parameter table of the cells.

[0084]

[0085] from Figure 9 As shown in Table 1, compared with Comparative Example 1, the device in Example 1 has higher short-circuit current density, open-circuit voltage and fill factor, and the device photoelectric conversion efficiency is significantly improved from 24.46% to 25.70%.

[0086] Figure 10 The results show the stability test results of the unencapsulated perovskite solar cells prepared in Example 1 and Comparative Example 1 under continuous maximum power point tracking conditions. Figure 10 As can be seen, compared to the perovskite solar cell of Comparative Example 1, which only retained 65.46% of its initial efficiency, the device in Example 1 was still able to maintain 85.71% of its initial efficiency after 850 hours of continuous light aging, indicating that the introduction of additives effectively improved the device's operational stability.

[0087] In summary, this invention discloses a method for simultaneously passivating defects and alleviating lattice strain. By introducing halogen-substituted aromatic amine organic ammonium salt additives into the perovskite precursor solution, it is possible to effectively promote the growth of high-quality perovskite crystals and passivate the defect density and residual strain in the thin film through interaction with the perovskite components.

[0088] In addition, the present invention also discloses an inverted perovskite solar cell. The inverted perovskite solar cell of the present invention can optimize the interface energy level matching between the perovskite layer and the carrier transport layer by adopting the above method, improve the carrier extraction and transport efficiency, and thus realize a high-efficiency and high-stability perovskite solar cell.

Claims

1. An additive based on halogen-substituted aromatic amine organic ammonium salts, characterized in that, The additive is an aromatic molecule containing halogen substituents and ammonium salt groups; the aromatic molecule containing halogen substituents and ammonium salt groups is 4-fluorobenzylamine hydrobromide, difluorobenzylamine hydrobromide, trifluoromethylbenzylamine hydrobromide, p-fluoroaniline hydrobromide, p-chloroaniline hydroiodide, or p-bromoaniline hydrobromide. The additive possesses both defect passivation and strain regulation functions. The organic ammonium salt molecules containing halogen substituents and amino functional groups interact with uncoordinated Pb in the perovskite film through the ammonium salt groups. 2+ Sn 2+ Or Ge 2+ Coordination is formed, and halogen substituents are used to regulate the crystallization and local electronic structure of perovskite, thereby improving the crystal quality of perovskite films and alleviating residual strain.

2. A perovskite light-absorbing layer, characterized in that, The perovskite light-absorbing layer is made of ABX3, where A is CH3NH3. + (MA) + CH(NH2)2 + (FA) + ), Cs + or Rb + One or more of them, B is Pb 2+ Sn 2+ Or Ge 2+ One or more of them, X is Cl - ,Br - or I - One or more of them; During the preparation of the perovskite light-absorbing layer, the additive described in claim 1 is directly added to the precursor solution. The functional groups in the additive passivate perovskite defects and alleviate lattice strain through their interaction with A, B, and X. The surface of the perovskite light-absorbing layer is more dense and uniform, and the grain size is significantly increased to 300~400 nm; the root mean square roughness of the perovskite light-absorbing layer is reduced to 13.8 nm, and the average carrier lifetime is increased to over 691.90 ns.

3. The method for preparing the perovskite light-absorbing layer according to claim 2, characterized in that, The steps include: (1) dissolving the perovskite precursor material in an organic solvent to form a perovskite precursor solution; (2) Add halogen-substituted aromatic amine organic ammonium salt additives to the perovskite precursor solution to form a modified precursor solution; (3) The modified precursor solution is spin-coated onto the surface of the modified layer on the hole transport layer, and anti-solvent treatment and thermal annealing are performed to form a perovskite film that takes into account both defect passivation and strain release.

4. The method for preparing the perovskite light-absorbing layer according to claim 3, characterized in that, In step (1), the concentration of the perovskite light-absorbing layer material in the perovskite precursor solution is 1.2~1.8 mol / L, and the solvent is one or more of N,N-dimethylformamide (DMF) or dimethyl sulfoxide (DMSO).

5. The method for preparing the perovskite light-absorbing layer according to claim 3, characterized in that, In step (2), the concentration of the halogen-substituted aromatic amine organic ammonium salt additive is 5 × 10⁻⁶. -3 ~7×10 -3 mmol / mL.

6. An inverted perovskite solar cell, characterized in that, The inverted perovskite solar cell uses the perovskite light-absorbing layer described in claim 2.

7. The inverted perovskite solar cell according to claim 6, characterized in that, The inverted perovskite solar cell comprises, from bottom to top, a transparent conductive substrate, a hole transport layer, a modification layer, a perovskite light-absorbing layer, an electron transport layer, and a metal electrode. The inverted perovskite solar cell has a photoelectric conversion efficiency of over 25.70%; it can still maintain an initial efficiency of 85.71% after 850 hours of continuous light aging.

8. The method for fabricating the inverted perovskite solar cell according to claim 6 or 7, characterized in that, The preparation method includes the following steps: (1) Disperse the hole transport layer material in isopropanol or deionized water, and then spin coat it onto the surface of the pretreated transparent conductive substrate at a speed of 3000~4000 rpm. After spin coating for 20~40 s, anneal at 100~150℃ for 10~30 min to form a hole transport layer on the surface of the transparent conductive substrate. (2) After diluting the oxide nanoscale dispersion, spin-coat it onto the hole transport layer at a speed of 2000~3000 rpm. After spin-coating for 30~40 s, anneal at 100~150℃ for 10~30 min, and then anneal at 100~120℃ for 10~30 min to form a modification layer on the surface of the hole transport layer. (3) Add the halogen-substituted aromatic amine organic ammonium salt additive to the perovskite precursor solution containing the perovskite light-absorbing layer, and drop it onto the surface of the modified layer. First spin coat at a speed of 1000~2000 rpm for 5~10 s, then spin coat at a speed of 3000~5000 rpm for 40~50 s. Add the antisolvent in the last 5~10 s of the spin coating, and then anneal at 100~120℃ for 20~30 min to prepare the perovskite light-absorbing layer film. (4) In 10 -5 Under high vacuum conditions of Pa, organic C with a thickness of 18~25 nm was deposited on the surface of the perovskite film by thermal evaporation. 60 , as an electron transport layer; (5) By depositing a metal electrode material with a thickness of 80~150 nm on the electron transport layer, an inverted perovskite solar cell can be prepared.

9. The method for fabricating the inverted perovskite solar cell according to claim 8, characterized in that, The transparent conductive substrate is made of either ITO or FTO. In step (1), the hole transport layer is made of ((4-(7H-dibenzo[c,g]carbazol-7-yl)butyl)phosphonic acid (CbzNaph), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], poly(3-hexylthiophene-2,5-diyl), (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid (Me-4PACz) or NiO. x Any one or more of the following; the material concentration of the hole transport layer is 0.5~30 mg / mL.

10. The method for fabricating the inverted perovskite solar cell according to claim 8, characterized in that, In step (2), the oxide is aluminum oxide, silicon oxide, or magnesium oxide; In step (3), the antisolvent is chlorobenzene (CB), ethyl acetate (EA), toluene, diethyl ether, or anisole; In step (5), the metal electrode material is any one of Au, Ag or Cu.

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