Perovskite solar cell and preparation method thereof

Abstract

This invention discloses a perovskite solar cell and its fabrication method. The method includes: spin-coating a mixed solution of lead iodide and HIAM-4024 or HIAM-4025 onto the surface of an electron transport layer, followed by annealing to obtain a lead iodide layer; and spin-coating an organic halide solution onto the surface of the lead iodide layer, followed by annealing to obtain a perovskite layer. This invention introduces HIAM-4024 or HIAM-4025 into the lead iodide layer, allowing high-energy photons to be filtered through HIAM-4024 or HIAM-4025. Through down-conversion, it emits photons in the visible light range, which are further utilized by the underlying perovskite absorber, thereby improving the light energy utilization of the perovskite solar cell. Furthermore, both HIAM-4024 and HIAM-4025 can effectively filter ultraviolet radiation that could damage the device, further enhancing the light energy utilization of the perovskite device.

Description

Technical Field

[0001] This invention relates to the field of solar photovoltaic technology, and in particular to a perovskite solar cell and its preparation method. Background Technology

[0002] Perovskite solar cells are a potentially disruptive technology in the photovoltaic field due to their excellent power conversion efficiency (currently the highest certified efficiency is 25.7%) and the promise of reduced costs due to their ease of solution handling. Currently, the instability of perovskite devices is a major challenge severely hindering their commercialization. Perovskite materials, with their ionic crystal structure, are unstable and rapidly degrade under high humidity, light, ultraviolet light, high temperature, and stress. First, perovskite crystals readily react with water and oxygen, initiating device decomposition; second, perovskite thin films evolve rapidly under continuous light or heating, including halogen separation and ion migration. Notably, I... - Pb 2+ The flexibility of the ions, coupled with the fragile Pb-I bonds, controls the intrinsic degradation process of materials. - and Pb 2+ It readily undergoes redox reactions, further generating iodine and metallic lead, initiating a chemical chain reaction and accelerating the degradation of perovskite. Furthermore, most researchers consider ultraviolet (UV) radiation to be the most destructive region of the solar spectrum. Various attempts to improve intrinsic materials and reduce deep defect states have been reported, such as doping, optimizing thin film processing, and grain boundary modification. However, these additives are mostly sacrificial agents for a single defect, with complex preparation processes, high costs, and unsuitability for industrial production.

[0003] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a perovskite solar cell and its preparation method, which aims to solve the problem that existing perovskite thin films have defects and ultraviolet radiation, resulting in low photoelectric conversion efficiency of the device.

[0005] The technical solution of the present invention is as follows:

[0006] A first aspect of the present invention provides a method for preparing a perovskite solar cell, comprising the steps of:

[0007] Provide a conductive substrate;

[0008] An electron transport layer is prepared on the surface of the conductive substrate;

[0009] A perovskite layer is prepared on the surface of the electron transport layer, the perovskite layer comprising a perovskite body and HIAM-4024 or HIAM-4025;

[0010] A hole transport layer is prepared on the surface of the perovskite layer;

[0011] An electrode is fabricated on the surface of the hole transport layer;

[0012] The step of preparing a perovskite layer on the surface of the electron transport layer specifically includes:

[0013] A mixed solution of lead iodide with HIAM-4024 or HIAM-4025 is provided; an organic halide solution is also provided.

[0014] A mixed solution of lead iodide and HIAM-4024 or HIAM-4025 is spin-coated onto the surface of the electron transport layer, and a first annealing treatment is performed to obtain a lead iodide layer.

[0015] The organic halide solution was spin-coated onto the surface of the lead iodide layer, and then subjected to a second annealing treatment to obtain the perovskite layer.

[0016] It is well known that ultraviolet radiation can cause oxygen vacancies and defects in perovskite crystals, thereby damaging perovskite devices. This invention introduces an organometallic framework material (MOF) HIAM-4024 or HIAM-4025 into the lead iodide layer. Both MOFs, based on their ligand structures, contain two amino groups (-NH2). HIAM-4024 contains sulfur (S), while HIAM-4025 contains selenium (Se). The amino groups effectively passivate vacancy defects on the perovskite surface and introduce higher divalent anion charges, significantly increasing electrostatic interactions. 2- and Se 2- Both are related to Pb 2+ Highly covalent chemical bonds are formed, resulting in a more stable perovskite structure. From the excitation and emission spectra, the excitation peak of HIAM-4024 is at 550 nm, and the emission peak is at 640 nm, while the excitation and emission peaks of HIAM-4025 are completely different, both shifting towards the near-infrared region, with values ​​of 610 nm and 788 nm. Perovskite materials exhibit strong absorption around 400 nm, and the photoluminescence wavelength is around 790 nm. Based on this, it was found that the excitation peaks of HIAM-4024 or HIAM-4025 overlap well with the absorption of perovskite, which satisfies the requirements for effective Förster resonance energy transfer from HIAM-4024 or HIAM-4025 to adjacent perovskite layers. The results indicate that high-energy photons may be filtered through the HIAM-4024 and HIAM-4025 layers. Through downconversion, it emits photons in the visible light range, which are then further utilized by the underlying perovskite absorber to improve the light energy utilization of the corresponding perovskite solar cell. The current density J is increased based on the spectral enhancement of the external quantum efficiency (EQE). scThe value reflects the occurrence of Förster resonance energy transfer. Furthermore, the modified perovskite device exhibits excellent photoelectric conversion efficiency.

[0017] This invention employs a two-step spin-coating technique to prepare a perovskite layer. In the first step, HIAM-4024 or HIAM-4025 is used to modify the lead iodide layer, which effectively forms a porous lead iodide layer. This facilitates the penetration of the organic halide solution in the second step, improves the conversion efficiency of the perovskite, and effectively reduces the defect states of the perovskite layer. It also promotes the carrier mobility and crystallinity of the perovskite layer, and enhances the stability and water resistance of the perovskite device, thereby improving the photoelectric conversion efficiency of the device.

[0018] Furthermore, this invention employs a two-step spin-coating process to prepare the perovskite layer, allowing for step-by-step control of the defect states within the perovskite layer. It also eliminates anti-solvents such as chlorobenzene, enabling rapid, large-area device production. Moreover, this spin-coating process is technically mature, simple to implement, and highly reproducible.

[0019] Optionally, the mass percentage of HIAM-4024 or HIAM-4025 in the perovskite layer is 0.1% to 10%.

[0020] Optionally, the perovskite matrix is ​​ABX3, wherein A includes methylamine cation, formamidinium cation, and cesium cation; B includes lead cation; and X includes chloride anion, bromide anion, and iodide anion.

[0021] Optionally, the method for preparing the mixed solution of lead iodide with HIAM-4024 or HIAM-4025 includes the following steps:

[0022] Lead iodide is dissolved in a solvent to obtain a lead iodide solution;

[0023] HIAM-4024 or HIAM-4025 is added to the lead iodide solution to obtain a mixed solution of lead iodide and HIAM-4024 or HIAM-4025.

[0024] The solvent is one or more of N,N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, and γ-butyrolactone.

[0025] Optionally, in the mixed solution of lead iodide and HIAM-4024 or HIAM-4025, the amount of lead iodide and HIAM-4024 or HIAM-4025 added is 1-3 mol and 0.1-8 mg, respectively.

[0026] Optionally, in the step of spin-coating the mixed solution of lead iodide and HIAM-4024 or HIAM-4025 onto the surface of the electron transport layer, the spin-coating parameters include: a rotation speed of 1000-5000 r / s and a time of 20-100 s;

[0027] And / or, the parameters of the first annealing treatment include: a temperature of 50-120 °C and a time of 50-150 s.

[0028] Optionally, the organic halide solution is a solution containing FAI, CsI, MACl, and MABr.

[0029] Optionally, the mass ratio of FAI, CsI, MACl, and MABr is (40-80):(10-30):(3-10):(3-10).

[0030] Optionally, in the step of spin-coating the organic halide solution onto the surface of the lead iodide layer, the spin-coating parameters include: a rotation speed of 1000-3000 r / s and a time of 40-120 s;

[0031] And / or, the parameters of the second annealing treatment include: a temperature of 80-150 ℃ and a time of 600-2000 s.

[0032] Optionally, the preparation method of HIAM-4024 includes the following steps: adding 10-30 mg ZrCl4, 5-20 mg H4BTATC, 500-1000 mg benzoic acid, and 6 mL DMF to a 10 mL beaker. The mixture is then heated in an oven at 100°C for 2 days. After cooling to room temperature, pale yellow crystals of HIAM-4024 are obtained.

[0033] Optionally, the preparation method of HIAM-4025 includes the following steps: adding 10-30 mg ZrCl4, 5-20 mg H4NSATC, 500-1000 mg benzoic acid, and 6 mL DMF to a 10 mL beaker. The mixture is then heated in an oven at 100°C for 2 days. After cooling to room temperature, pale yellow crystals of HIAM-4025 are obtained.

[0034] A second aspect of the present invention provides a perovskite solar cell, wherein the perovskite solar cell is prepared using the method described in the present invention. Attached Figure Description

[0035] Figure 1 In the figures (a) and (b), the ligand structures of the MOF materials HIAM-4024 and HIAM-4025 prepared in this invention are respectively.

[0036] Figure 2It is the topology of HIAM-4024 and HIAM-4025.

[0037] Figure 3 In the middle (a) and (b), scanning electron microscope images of the MOF materials HIAM-4024 and HIAM-4025 prepared in this invention are respectively.

[0038] Figure 4 These are excitation and emission spectra of perovskite, HIAM-4024, and HIAM-4025.

[0039] Figure 5 The graphs show the external quantum efficiency (EQE) of the control group and the MOF-modified perovskite solar cell. Detailed Implementation

[0040] This invention provides a perovskite solar cell and its fabrication method. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0041] This invention provides a method for fabricating a perovskite solar cell, comprising the following steps:

[0042] (1) Provide a conductive substrate;

[0043] (2) An electron transport layer is prepared on the surface of the conductive substrate;

[0044] (3) A perovskite layer is prepared on the surface of the electron transport layer, wherein the perovskite layer comprises a perovskite body and HIAM-4024 or HIAM-4025;

[0045] (4) A hole transport layer is prepared on the surface of the perovskite layer;

[0046] (5) An electrode is fabricated on the surface of the hole transport layer;

[0047] Step (3) specifically includes:

[0048] A mixed solution of lead iodide with HIAM-4024 or HIAM-4025 is provided; an organic halide solution is also provided.

[0049] A mixed solution of lead iodide and HIAM-4024 or HIAM-4025 is spin-coated onto the surface of the electron transport layer, and a first annealing treatment is performed to obtain a lead iodide layer.

[0050] The organic halide solution was spin-coated onto the surface of the lead iodide layer, and then subjected to a second annealing treatment to obtain the perovskite layer.

[0051] This embodiment introduces an organometallic framework material (MOF material) HIAM-4024 or HIAM-4025 into the lead iodide layer. These two MOFs, from their ligand structures, are as follows: Figure 1 As shown, all contain two amino groups (-NH2). HIAM-4024 contains sulfur (S), while HIAM-4025 contains selenium (Se). The amino groups effectively passivate vacancy defects on the perovskite surface and introduce higher divalent anion charges, significantly increasing electrostatic interactions. 2- and Se 2- Both are related to Pb 2+ Highly covalent chemical bonds are formed, resulting in a more stable perovskite structure. From the excitation and emission spectra, the excitation peak of HIAM-4024 is at 550 nm, and the emission peak is at 640 nm, while the excitation and emission peaks of HIAM-4025 are completely different, both shifting towards the near-infrared region, with values ​​of 610 nm and 788 nm. Perovskite materials exhibit strong absorption around 400 nm, and the photoluminescence wavelength is around 790 nm. Based on this, it was found that the excitation peaks of HIAM-4024 or HIAM-4025 overlap well with the absorption of perovskite, thus satisfying the requirements for effective Förster resonance energy transfer from HIAM-4024 or HIAM-4025 to adjacent perovskite layers. The results indicate that high-energy photons may be filtered through the HIAM-4024 and HIAM-4025 layers. Through downconversion, it emits photons in the visible light range, which are then further utilized by the underlying perovskite absorber to improve the light energy utilization of the corresponding perovskite solar cell. The current density J is increased based on the spectral enhancement of the external quantum efficiency (EQE). sc The value reflects the occurrence of Förster resonance energy transfer. Furthermore, the modified perovskite device exhibits excellent photoelectric conversion efficiency.

[0052] This invention employs a two-step spin-coating technique to prepare a perovskite layer. In the first step, HIAM-4024 or HIAM-4025 is used to modify the lead iodide layer, which effectively forms a porous lead iodide layer. This facilitates the penetration of the organic halide solution in the second step, improves the conversion efficiency of the perovskite, and effectively reduces the defect states of the perovskite layer. It also promotes the carrier mobility and crystallinity of the perovskite layer, and enhances the stability and water resistance of the perovskite device, thereby improving the photoelectric conversion efficiency of the device.

[0053] Furthermore, this invention employs a two-step spin-coating process to prepare the perovskite layer, allowing for step-by-step control of the defect states within the perovskite layer. It also eliminates anti-solvents such as chlorobenzene, enabling rapid, large-area device production. Moreover, this spin-coating process is technically mature, simple to implement, and highly reproducible.

[0054] In one embodiment, the preparation method of HIAM-4024 includes the following steps: adding 10-30 mg ZrCl4 and 5-20 mg H4BTATC (structural formula see below) to a 10 mL beaker. Figure 1 A mixture of 500-1000 mg benzoic acid and 6 mL DMF was obtained. The mixture was heated in an oven at 100 °C for 2 days. After cooling to room temperature, pale yellow crystals HIAM-4024 were obtained. The preparation route of HIAM-4024 is basically similar to that of HIAM-4001 (see Ren D, et al. Angewandte Chemie, 2021, 133(47): 25252-25258.), the main difference being the different ligands used.

[0055] In one embodiment, the preparation method of HIAM-4025 includes the following steps: adding 10-30 mg ZrCl4 and 5-20 mg H4NSATC (structural formula see below) to a 10 mL beaker. Figure 1 (b) 500-1000 mg of benzoic acid and 6 mL of DMF were added to obtain a mixture. The mixture was heated in an oven at 100 °C for 2 days. After cooling to room temperature, pale yellow crystals HIAM-4025 were obtained. The preparation route of HIAM-4025 is basically similar to that of HIAM-4001 (Ren D, et al. AngewandteChemie, 2021, 133(47): 25252-25258.), the main difference being the different ligands used.

[0056] Where HIAM = Hoffmann Institute of Advanced Materials; 40 = zirconium; 25 = ligand 1 (H4BTATC), 26 = ligand 2 (H4NSATC)

[0057] In one embodiment, the mass percentage of HIAM-4024 or HIAM-4025 in the perovskite layer is 0.1% to 10%. This is because a small amount of HIAM-4024 or HIAM-4025 material can not only passivate the perovskite layer and reduce defect states, but also improve the light energy utilization of the corresponding perovskite solar cell.

[0058] In one embodiment, the perovskite body is ABX3, wherein A includes methylamine cation, cesium cation, and formamidinium cation; B includes lead cation; and X includes chloride anion, bromide anion, and iodide anion.

[0059] In step (1), in one embodiment, the conductive substrate is a transparent rigid conductive substrate or a transparent flexible conductive substrate. Further, the transparent rigid conductive substrate can be, but is not limited to, an ITO substrate, an FTO substrate, etc. Further, the transparent flexible conductive substrate can be, but is not limited to, a PET substrate, a PEN substrate, etc.

[0060] In one embodiment, the conductive substrate is a conductive substrate that has undergone cleaning and UV treatment. Specifically, the conductive substrate is first cleaned; then, the cleaned conductive substrate is UV treated to improve its hydrophilicity. The cleaning steps may include: sequentially ultrasonically cleaning the conductive substrate with a mixture of deionized water and detergent, and then with deionized water and isopropanol, followed by drying with nitrogen gas.

[0061] In step (2), in one embodiment, the step of preparing an electron transport layer on the surface of the conductive substrate specifically includes:

[0062] Preparation of electron transport material solution;

[0063] The electron transport material solution is coated onto the surface of a conductive substrate using a solution method (such as spin coating), and then annealed to obtain the electron transport layer.

[0064] In one embodiment, the electron transport material solution can be an organic electron transport material solution, such as a PCBM solution or C 60 solution etc.

[0065] In one embodiment, the electron transport material solution may also be an inorganic electron transport material solution, such as a titanium dioxide solution or a tin dioxide solution.

[0066] In step (3), the perovskite layer solution is prepared in two parts: a mixed solution of lead iodide and HIAM-4024 or HIAM-4025, and an organic halide solution. After weighing the reagents, solvents are added to each solution and dissolved evenly to obtain the mixed solution of lead iodide and HIAM-4024 or HIAM-4025 and the organic halide solution, respectively. After spin coating and annealing, the perovskite layer is obtained. That is, this embodiment uses a two-step spin coating method to prepare the perovskite layer.

[0067] In one embodiment, the method for preparing the mixed solution of lead iodide with HIAM-4024 or HIAM-4025 includes the following steps:

[0068] Lead iodide is dissolved in a solvent to obtain a lead iodide solution;

[0069] HIAM-4024 or HIAM-4025 is added to the lead iodide solution to obtain a mixed solution of lead iodide and HIAM-4024 or HIAM-4025; wherein the solvent can be one or more of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), γ-butyrolactone, etc.

[0070] In one embodiment, in the mixed solution of lead iodide and HIAM-4024 or HIAM-4025, the amount of lead iodide and HIAM-4024 or HIAM-4025 added is 1-3 mol and 0.1-8 mg, respectively.

[0071] In one embodiment, in the step of spin-coating the mixed solution of lead iodide and HIAM-4024 or HIAM-4025 onto the surface of the electron transport layer, the spin-coating parameters include: a rotation speed of 1000-5000 r / s and a time of 20-100s.

[0072] In one embodiment, the parameters of the first annealing treatment (performed in an inert atmosphere in a glove box) include: a temperature of 50-120 °C and a time of 50-150 s.

[0073] In one embodiment, the organic halide solution can be a solution containing FAI, CsI, MACl, or MABr, wherein the solvent can be IPA (isopropanol), etc., but is not limited thereto. Using mixed cations and halogens is more conducive to the transformation of the perovskite phase and inhibits the formation of non-perovskite phases.

[0074] Furthermore, the mass ratio of FAI, CsI, MACl, and MABr is (40-80):(10-30):(3-10):(3-10). Using mixed cations and halogens within this mass ratio range is more conducive to the transformation of the perovskite phase and inhibits the formation of non-perovskite phases.

[0075] In one embodiment, in the step of spin-coating the organic halide solution onto the surface of the lead iodide layer, the spin-coating parameters include: a rotation speed of 1000-3000 r / s and a time of 40-120 s.

[0076] In one embodiment, the parameters of the second annealing treatment (performed in a drying oven environment) include: a temperature of 80-150 °C and a time of 600-2000 s.

[0077] In step (4), a hole transport layer is prepared. In one embodiment, the step of preparing the hole transport layer on the surface of the perovskite layer specifically includes:

[0078] Provide hole transport material solution;

[0079] The hole transport material solution is coated onto the surface of the perovskite layer using a solution method (such as spin coating), and then annealed to form the hole transport layer.

[0080] In one embodiment, the hole transport material solution can be an organic hole transport material solution, such as Spiro-OMeTAD solution, PTAA solution, etc.

[0081] In one embodiment, the hole transport material solution may also be an inorganic hole transport material solution, such as nickel oxide or copper oxide.

[0082] In step (5), electrodes are prepared. Metal electrodes can be prepared on the surface of the hole transport layer by vapor deposition, and finally a perovskite solar cell is obtained.

[0083] This invention provides a perovskite solar cell, which is prepared using the method described in this invention.

[0084] The present invention will be further described below through specific embodiments.

[0085] In the following examples, the materials ITO, PET, tin oxide, nickel oxide, lead iodide, formamidinium iodide, methylamine chloride, N,N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, Sprio-OMeTAD, and PCBM are all commercially available products. The MOF materials HIAM-4024 and HIAM-4025 were synthesized in-house.

[0086] 1. The preparation steps of HIAM-4024 are as follows: Add 20 mg ZrCl4, 10 mg H4BTATC, 800 mg benzoic acid, and 6 mL DMF to a 10 mL beaker to obtain a mixture. Heat the mixture in an oven at 100℃ for 2 days. After cooling to room temperature, pale yellow crystals of HIAM-4024 are obtained.

[0087] 2. The preparation steps of HIAM-4025 are as follows: Add 20 mg ZrCl4, 10 mg H4NSATC, 800 mg benzoic acid, and 6 mL DMF to a 10 mL beaker to obtain a mixture. Heat the mixture in a 100℃ oven for 2 days. After cooling to room temperature, pale yellow crystals of HIAM-4025 are obtained.

[0088] 3. Fabrication of HIAM-4024 modified perovskite solar cells:

[0089] First, the ITO substrate was placed in a beaker and ultrasonically cleaned for 30 min in a solution of deionized water and detergent, followed by ultrasonic cleaning in deionized water for 30 min, and finally ultrasonic cleaning in isopropanol for 30 min. After completion, it was dried with nitrogen gas. The cleaned ITO substrate was then placed in a UV instrument and treated with ozone for 30 min.

[0090] Next, the perovskite layer solution was prepared. 1 mol of lead iodide was dissolved in 1 mL of DMF solution, followed by the addition of 5 mg of HIAM-4024 powder, resulting in a mixed solution of lead iodide and HIAM-4024. FAI, CsI, MACl, and MABr were dissolved in IPA and stirred until homogeneous, yielding an organohalide solution; the mass concentrations of FAI, CsI, MACl, and MABr were 80 mg / mL, 20 mg / mL, 7 mg / mL, and 7 mg / mL, respectively.

[0091] The preparation of perovskite thin films involves two steps. The spin coater parameters are set as follows: 2000 r / s for 30 s. Step 1: A mixed solution of lead iodide and HIAM-4024 is dropped onto the ITO substrate surface, and the spin coater is turned on. After spin coating, the sample is annealed at 70℃ for 80 s and then cooled for later use. Step 2: An organic halide solution is added dropwise to the sample from Step 1, using the same spin coater parameters. After spin coating, the sample is placed on a heating stage and annealed at 150℃ for 2000 min. After cooling to room temperature, the preparation is complete.

[0092] Next, a spin-coating process was performed using Spiro-OMeTAD solution. The Spiro-OMeTAD solution was prepared as follows: 78 mg Spiro-OMeTAD, 40 μL TBP (tributyl phosphate), and 40 μL LiTFSI solution (acetonitrile as the solvent, 460 mg LiTFSI, 1 mL acetonitrile) were mixed in 1 mL of chlorobenzene. The spin-coating parameters were set to 4000 r / s for 20 s. The Spiro-OMeTAD solution was dropped onto the perovskite layer surface, the spin-coator was turned on, and the layer was left to oxidize overnight to obtain the hole transport layer.

[0093] Finally, a gold electrode with a thickness of about 100 nm was deposited on the surface of the hole transport layer to obtain a perovskite solar cell.

[0094] 4. Preparation of HIAM-4025 modified perovskite solar cells: The preparation is the same as that of HIAM-4024 modified perovskite solar cells, except that HIAM-4025 powder is added instead of HIAM-4024 powder in the perovskite layer.

[0095] 5. Preparation of perovskite solar cells in the control example: The preparation is the same as that of HIAM-4024 modified perovskite solar cells, except that HIAM-4024 powder is not added to the perovskite layer.

[0096] Figure 1 (a) and (b) are the ligand structures of the MOF materials HIAM-4024 and HIAM-4025 prepared in this embodiment, respectively. Both MOF materials contain two amino molecules, which can effectively passivate vacancy defects on the perovskite surface. HIAM-4024 contains an S atom, and HIAM-4025 contains a Se atom; the divalent S... 2- and Se 2- Both are related to Pb 2+ This forms highly covalent chemical bonds, resulting in a more stable perovskite structure. Figure 2 These are the topologies of HIAM-4024 and HIAM-4025. They have similar three-dimensional topologies. Figure 3 These are scanning electron microscope images of HIAM-4024 and HIAM-4025. A rice-grain-like structure can be observed, with a particle size of approximately less than 100 nm. Figure 4 These are the excitation and emission spectra of perovskite, HIAM-4024, and HIAM-4025. The spectra show that HIAM-4024 has an excitation peak at 550 nm and an emission peak at 640 nm, while HIAM-4025 exhibits completely different excitation and emission peaks, both located near the near-infrared region, with values ​​of 610 nm and 788 nm, respectively. Perovskite materials show strong absorption around 400 nm, and the photoluminescence (PL) wavelength is around 790 nm. The excitation peaks of HIAM-4024 or HIAM-4025 overlap well with the absorption of perovskite, which would satisfy the requirements for effective Förster resonance energy transfer from HIAM-4024 or HIAM-4025 to adjacent perovskite layers. The results indicate that high-energy photons may be filtered through the HIAM-4024 and HIAM-4025 layers. Through downconversion, it emits photons in the visible light range. These photons are further utilized by the perovskite absorber below to improve the light energy utilization of the corresponding perovskite solar cell. The result is reflected in the external quantum efficiency (EQE) spectrum, such as... Figure 5 As shown. Figure 5The graphs show the external quantum efficiency (EQE) of the control group and the MOF-modified perovskite devices. It was found that in the wavelength range of 300-700 nm, the EQE of the perovskite solar cells modified with HIAM-4024 or HIAM-4025 was significantly improved, with this improvement attributed to the Förster resonance energy transfer effect. The improvement in the wavelength range of 700-900 nm is attributed to the higher crystal quality of the perovskite film. This indicates that both HIAM-4024 and HIAM-4025 MOF materials can effectively filter ultraviolet radiation that could damage the device, thus improving the light energy utilization of perovskite solar cells.

[0097] Example 1

[0098] The fabrication method of the perovskite solar cell in this embodiment includes the following steps:

[0099] (1) Cleaning and UV treatment of ITO substrate. First, the ITO substrate was placed in a beaker and ultrasonically cleaned in deionized water and detergent solution for 30 min, then ultrasonically cleaned in deionized water for 30 min, and finally ultrasonically cleaned in isopropanol for 30 min. After completion, it was dried with nitrogen. The cleaned ITO substrate was placed in a UV instrument and treated with ozone for 30 min.

[0100] (2) A tin dioxide electron transport layer was prepared using a spin coating process. A tin dioxide solution was prepared (the tin dioxide solution was diluted with deionized water at a volume ratio of 1:8). The spin coater parameters were set as follows: 2000 r / s, running for 60 s. The tin dioxide solution was dropped onto the UV-treated ITO substrate surface, and the spin coater was turned on. After spin coating was completed, the sample was placed on a heating stage and annealed at 120 ℃ for 20 min.

[0101] (3) The perovskite layer was prepared by a two-step spin-coating method. The specific preparation steps are as follows:

[0102] Prepare a solution for the perovskite layer. Dissolve 1.2 mol of lead iodide in 1 mL of DMF solution, then add 8 mg of HIAM-4024 powder to obtain a mixed solution of lead iodide and HIAM-4024. Dissolve FAI, CsI, MACl, and MABr in IPA and stir until homogeneous to obtain an organohalide solution; wherein the mass concentrations of FAI, CsI, MACl, and MABr are 80 mg / mL, 10 mg / mL, 6 mg / mL, and 6 mg / mL, respectively.

[0103] The preparation of the perovskite layer consists of two steps. Step 1: The ITO substrate with the electron transport layer is UV-treated for 30 min. The spin coater parameters are set to 1800 r / s for 20 s. A mixed solution of lead iodide and HIAM-4024 is dropped onto the electron transport layer surface, and the spin coater is turned on. After spin coating, the sample is annealed at 60℃ for 50 s and then cooled for later use. Step 2: An organic halide solution is added dropwise to the sample from Step 1, using the same spin coater parameters. After spin coating, the sample is placed on a heating stage and annealed at 110℃ for 30 min, then cooled for later use.

[0104] (4) The Spiro-OMeTAD hole transport layer was prepared by spin coating. The Spiro-OMeTAD solution was prepared as follows: 78 mg Spiro-OMeTAD, 40 μL TBP (tributyl phosphate), and 40 μL LiTFSI solution (acetonitrile as the solvent, 460 mg LiTFSI, 1 mL acetonitrile) were mixed in 1 mL of chlorobenzene. The spin coater parameters were set to 4000 r / s for 20 s. The Spiro-OMeTAD solution was dropped onto the perovskite layer surface, the spin coater was turned on, and the layer was left to oxidize overnight to obtain the hole transport layer.

[0105] (5) A gold electrode with a thickness of about 100 nm is deposited on the surface of the hole transport layer to obtain a perovskite solar cell.

[0106] Example 2

[0107] The fabrication method of the perovskite solar cell in this embodiment includes the following steps:

[0108] (1) Cleaning and UV treatment of FTO substrate. First, the FTO substrate was placed in a beaker and ultrasonically cleaned for 30 min in deionized water and detergent solution, then ultrasonically cleaned for 30 min in deionized water, and finally ultrasonically cleaned for 30 min in isopropanol. After completion, it was dried with nitrogen gas. The cleaned FTO substrate was placed in a UV instrument and treated with ozone for 30 min.

[0109] (2) A tin dioxide electron transport layer was prepared using a spin coating process. A tin dioxide solution was prepared (the volume ratio of tin dioxide solution to deionized water was 1:7). The parameters of the spin coater were set as follows: rotation speed of 2500 r / s, running for 50 s. The tin dioxide solution was dropped onto the UV-treated FTO substrate surface, the spin coater was turned on, and after spin coating was completed, the sample was placed on a heating stage and annealed at 150℃ for 40 min.

[0110] (3) The perovskite layer was prepared by a two-step spin-coating method. The specific preparation steps are as follows:

[0111] A solution for preparing the perovskite layer was prepared. 1.8 mol of lead iodide was dissolved in a mixed solution of 940 μL DMF and 60 μL DMSO, followed by the addition of 2 mg of HIAM-4025 powder to obtain a mixed solution of lead iodide and HIAM-4025. FAI, CsI, MACl, and MABr were dissolved in IPA and stirred until homogeneous to obtain an organohalide solution; the mass concentrations of FAI, CsI, MACl, and MABr were 50 mg / mL, 20 mg / mL, 7 mg / mL, and 7 mg / mL, respectively.

[0112] The preparation of the perovskite active layer consists of two steps. Step 1: The FTO substrate with an electron transport layer is UV-treated for 30 min. The spin coater parameters are set to 3100 r / s for 50 s. A mixed solution of lead iodide and HIAM-4025 is dropped onto the electron transport layer surface, and the spin coater is turned on. After spin coating, the sample is annealed at 80℃ for 50 s and then cooled for later use. Step 2: An organic halide solution is added dropwise to the sample from Step 1, with the same spin coater parameters. After spin coating, the sample is placed on a heating stage and annealed at 130℃ for 40 min, then cooled for later use.

[0113] (4) The Spiro-OMeTAD hole transport layer was prepared by spin coating. The Spiro-OMeTAD solution was prepared as follows: 78 mg Spiro-OMeTAD, 40 μL TBP (tributyl phosphate), and 40 μL LiTFSI solution (acetonitrile as the solvent, 460 mg LiTFSI, 1 mL acetonitrile) were mixed in 1 mL of chlorobenzene. The spin coater parameters were set to 4000 r / s for 20 s. The Spiro-OMeTAD solution was dropped onto the perovskite layer surface, the spin coater was turned on, and the layer was left to oxidize overnight to obtain the hole transport layer.

[0114] (5) A gold electrode with a thickness of about 100 nm is deposited on the surface of the hole transport layer to obtain a perovskite solar cell.

[0115] Example 3

[0116] The fabrication method of the perovskite solar cell in this embodiment includes the following steps:

[0117] (1) Cleaning and UV treatment of ITO substrate. First, the ITO substrate was placed in a beaker and ultrasonically cleaned in deionized water and detergent solution for 30 min, then ultrasonically cleaned in deionized water for 30 min, and finally ultrasonically cleaned in isopropanol for 30 min. After completion, it was dried with nitrogen. The cleaned ITO substrate was placed in a UV instrument and treated with ozone for 30 min.

[0118] (2) The nickel oxide electron transport layer was prepared by spin coating. 30 mmol of nickel nitrate was dissolved in 40 mL of deionized water, and then 5 mL of NaOH solution (5 mol·L⁻¹) was slowly added dropwise. -1 After stirring for 30 min, the precipitate was washed three times with deionized water and dried under vacuum at 50 °C overnight. The obtained nickel oxide powder was dispersed in IPA (nickel oxide concentration 20 mg·mL⁻¹). -1 Stir for 60 minutes, then spin-coat the filtered solution onto the ITO substrate surface. Set the spin coater parameters as follows: 1500 r / s, run for 40 s. Turn on the spin coater and set aside for later use after spin coating is complete.

[0119] (3) The perovskite layer was prepared by a two-step spin-coating method. The specific preparation steps are as follows:

[0120] A solution for preparing the perovskite layer was prepared. 1.5 mol of lead iodide was dissolved in a mixed solution of 920 μL DMF and 80 μL DMSO, followed by the addition of 7 mg of HIAM-4024 powder, yielding a mixed solution of lead iodide and HIAM-4024. FAI, CsI, MACl, and MABr were dissolved in IPA and stirred until homogeneous, yielding an organohalide solution; the mass concentrations of FAI, CsI, MACl, and MABr were 90 mg / mL, 30 mg / mL, 8 mg / mL, and 8 mg / mL, respectively.

[0121] The preparation of the perovskite layer consists of two steps. Step 1: The ITO substrate with the electron transport layer is UV-treated for 30 min. The spin coater parameters are set to 3000 r / s for 30 s. A mixed solution of lead iodide and HIAM-4024 is dropped onto the electron transport layer surface, and the spin coater is turned on. After spin coating, the sample is annealed at 60℃ for 70 s and then cooled for later use. Step 2: An organic halide solution is added dropwise to the sample from Step 1, using the same spin coater parameters. After spin coating, the sample is placed on a heating stage and annealed at 115℃ for 30 min, then cooled for later use.

[0122] (4) C is deposited by vacuum thermal evaporation. 60 (Thickness 28 nm) The perovskite solar cell was successfully fabricated.

[0123] Example 4

[0124] The fabrication method of the perovskite solar cell in this embodiment includes the following steps:

[0125] (1) Cleaning and UV treatment of ITO substrate. First, the ITO substrate was placed in a beaker and ultrasonically cleaned in deionized water and detergent solution for 30 min, then ultrasonically cleaned in deionized water for 30 min, and finally ultrasonically cleaned in isopropanol for 30 min. After completion, it was dried with nitrogen. The cleaned ITO substrate was placed in a UV instrument and treated with ozone for 30 min.

[0126] (2) The nickel oxide electron transport layer was prepared by spin coating. 12 mmol of nickel nitrate was dissolved in 60 mL of deionized water, and then 11 mL of NaOH solution (5 mol·L⁻¹) was slowly added dropwise. -1 After stirring for 30 min, the precipitate was washed three times with deionized water and dried under vacuum at 60 °C overnight. The obtained nickel oxide powder was dispersed in IPA (nickel oxide concentration of 18 mg·mL⁻¹). -1 Stir for 30 minutes, then spin-coat the filtered solution onto the ITO substrate surface. Set the spin coater parameters to 3300 rpm for 60 seconds. Turn on the spin coater and set aside for later use after spin coating is complete.

[0127] (3) The perovskite layer was prepared by a two-step spin-coating method. The specific preparation steps are as follows:

[0128] Prepare a solution for the perovskite layer. Dissolve 1.5 mol of lead iodide in 1 mL of NMP solution, then add 2 mg of HIAM-4025 powder to obtain a mixed solution of lead iodide and HIAM-4025. Dissolve FAI, CsI, MACl, and MABr in IPA and stir until homogeneous to obtain an organohalide solution; wherein the mass concentrations of FAI, CsI, MACl, and MABr are 65 mg / mL, 25 mg / mL, 5 mg / mL, and 5 mg / mL, respectively.

[0129] The preparation of the perovskite layer consists of two steps. Step 1: The ITO substrate with an electron transport layer is UV-treated for 20 min. The spin coater parameters are set to 2200 r / s for 40 s. A mixed solution of lead iodide and HIAM-4025 is dropped onto the substrate surface, and the spin coater is turned on. After spin coating, the sample is annealed at 80℃ for 100 s and then cooled for later use. Step 2: An organic halide solution is added dropwise to the substrate, using the same spin coater parameters as in Step 1. After spin coating, the sample is placed on a heating stage and annealed at 150℃ for 50 min, then cooled for later use.

[0130] (4) The PCBM hole transport layer was prepared by spin coating. The PCBM solution was prepared as follows: 40 mg of PCBM was dissolved in 1 mL of chlorobenzene. The spin coater parameters were set as follows: 4000 r / s, running for 40 s. The PCBM solution was dropped onto the perovskite layer surface, the spin coater was turned on, and the layer was left to oxidize overnight to obtain the hole transport layer.

[0131] (5) A silver electrode with a thickness of about 90 nm is deposited on the surface of the hole transport layer to obtain a perovskite solar cell.

[0132] Comparative example: Same as Example 1, except that HIAM-4024 powder is not added in step (3).

[0133] The photoelectric conversion efficiency of the perovskite solar cells prepared in Examples 1-4 and the control example was tested using a steady-state calibrated solar simulator. The test results are shown in Table 1. As can be seen from Table 1, adding a small amount of HIAM-4024 or HIAM-4025 to the perovskite film can effectively improve its photoelectric conversion efficiency.

[0134] Table 1. Performance of perovskite solar cells prepared in each embodiment

[0135]

[0136] In summary, this invention provides a perovskite solar cell and its fabrication method. This invention introduces HIAM-4024 or HIAM-4025 into the lead iodide layer, allowing high-energy photons to be filtered. Through down-conversion, it emits photons in the visible light range, which are then further utilized by the underlying perovskite absorber, thereby improving the light energy utilization of the perovskite solar cell. Furthermore, both HIAM-4024 and HIAM-4025 effectively filter ultraviolet radiation that could damage the device, further enhancing the light energy utilization of the perovskite device.

[0137] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for preparing a perovskite solar cell, characterized in that, Including the following steps: Provide a conductive substrate; An electron transport layer is prepared on the surface of the conductive substrate; A perovskite layer is prepared on the surface of the electron transport layer, the perovskite layer comprising a perovskite body and HIAM-4024 or HIAM-4025; A hole transport layer is prepared on the surface of the perovskite layer; An electrode is fabricated on the surface of the hole transport layer; The step of preparing a perovskite layer on the surface of the electron transport layer specifically includes: A mixed solution of lead iodide with HIAM-4024 or HIAM-4025 is provided; an organic halide solution is also provided. A mixed solution of lead iodide and HIAM-4024 or HIAM-4025 is spin-coated onto the surface of the electron transport layer, and a first annealing treatment is performed to obtain a lead iodide layer. The organic halide solution was spin-coated onto the surface of the lead iodide layer, and then subjected to a second annealing treatment to obtain the perovskite layer; The organometallic framework material HIAM-4024 is prepared by mixing ZrCl4, H4BTATC, benzoic acid and DMF; The organometallic framework material HIAM-4025 is prepared by mixing ZrCl4, H4NSATC, benzoic acid and DMF.

2. The method for preparing a perovskite solar cell according to claim 1, characterized in that, In the perovskite layer, the mass percentage of HIAM-4024 or HIAM-4025 is 0.1% to 10%. The perovskite matrix is ​​ABX3, wherein A includes methylamine cation, formamidinium cation, and cesium cation; B includes lead cation; and X includes chloride anion, bromide anion, and iodide anion.

3. The method for preparing a perovskite solar cell according to claim 1, characterized in that, The method for preparing the mixed solution of lead iodide with HIAM-4024 or HIAM-4025 includes the following steps: Lead iodide is dissolved in a solvent to obtain a lead iodide solution; HIAM-4024 or HIAM-4025 is added to the lead iodide solution to obtain a mixed solution of lead iodide and HIAM-4024 or HIAM-4025. The solvent is one or more of N,N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, and γ-butyrolactone.

4. The method for preparing a perovskite solar cell according to claim 1, characterized in that, In the mixed solution of lead iodide and HIAM-4024 or HIAM-4025, the amount of lead iodide and HIAM-4024 or HIAM-4025 added are 1-3 mol and 0.1-8 mg, respectively.

5. The method for preparing a perovskite solar cell according to claim 1, characterized in that, In the step of spin-coating the mixed solution of lead iodide and HIAM-4024 or HIAM-4025 onto the surface of the electron transport layer, the spin-coating parameters include: a rotation speed of 1000-5000 r / s and a time of 20-100 s. And / or, the parameters of the first annealing treatment include: a temperature of 50-120 °C and a time of 50-150 s.

6. The method for preparing a perovskite solar cell according to claim 1, characterized in that, The organic halide solution is a solution containing FAI, CsI, MACl, and MABr.

7. The method for preparing a perovskite solar cell according to claim 6, characterized in that, The mass ratio of FAI, CsI, MACl, and MABr is (40-80):(10-30):(3-10):(3-10).

8. The method for preparing a perovskite solar cell according to claim 1, characterized in that, In the step of spin-coating the organic halide solution onto the surface of the lead iodide layer, the spin-coating parameters include: a rotation speed of 1000-3000 r / s and a time of 40-120 s; And / or, the parameters of the second annealing treatment include: a temperature of 80-150 ℃ and a time of 600-2000 s.

9. The method for preparing a perovskite solar cell according to claim 1, characterized in that, The preparation method of HIAM-4024 includes the following steps: mixing 10~30 mg ZrCl4, 5~20 mg H4BTATC, 500~1000 mg benzoic acid and 6 mL DMF to obtain a mixture; heating the mixture in an oven at 100℃ for 2 days; and cooling to room temperature to obtain HIAM-4024. Alternatively, the preparation method of HIAM-4025 includes the following steps: mixing 10~30 mg ZrCl4, 5~20 mg H4NSATC, 500~1000 mg benzoic acid and 6 mL DMF to obtain a mixture; heating the mixture in an oven at 100°C for 2 days; and cooling to room temperature to obtain HIAM-4025.

10. A perovskite solar cell, characterized in that, It is prepared by the method described in any one of claims 1-9.

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