Perovskite cell interface passivation method

Abstract

The invention belongs to the technical field of batteries, and relates to a perovskite battery interface passivation method. The preparation method comprises the following steps: dropwise adding a nickel oxide solution on an ITO substrate, uniformly spin-coating, and then drying, so that a nickel oxide nano-particle layer is cured; dropwise adding an ammonium polyphosphate solution on the cured nickel oxide nano-particle layer, and drying after uniformly spin-coating; coating the perovskite precursor solution on the surface of the ammonium polyphosphate layer of the substrate by adopting a two-step spin coating method, and annealing to complete the preparation of the perovskite layer; preparing an electron transport layer on the perovskite layer; and preparing a gold electrode on the electron transport layer. Ammonium polyphosphate is adopted for passivation of the upper interface and the lower interface of perovskite, phosphate groups of the lower interface and Ni < 2 + > / Ni < 3 + > form a strong coordination structure, a stable buried interface is formed, iodine vacancy forming energy is enhanced, defect states of the lower interface of the film are reduced, phosphate groups of the upper interface can be bonded with uncoordinated Pb < 2 + >, and therefore the defect states of the upper interface of the film are reduced, and the performance of the film is improved. The upper interface and the lower interface of the perovskite solar cell are good in dispersity.

Description

Technical Field

[0001] The invention belongs to the technical field of batteries and relates to a perovskite battery interface passivation method. Background Art

[0002] As a new photovoltaic technology with great potential, the optimization of perovskite solar cells has always been a hot topic in the research field. However, various defects often exist at the upper and lower interfaces of perovskite materials. These defects become the center of non-radiative recombination, which greatly affects the photoelectric conversion efficiency of the cell. Non-radiative recombination refers to the recombination of photogenerated carriers through defects before they are effectively utilized, thereby releasing heat energy instead of electrical energy, which not only reduces the generation of effective current, but also may lead to a significant decrease in battery performance.

[0003] Interface passivation technology can effectively inhibit or passivate defects. This technology effectively inhibits or passivates defects on the perovskite interface by introducing specific passivation materials, reducing the non-radiative recombination rate, thereby improving battery efficiency. However, most of the widely used passivation materials are organic materials. These materials have poor dispersibility in practical applications, which is not conducive to battery efficiency.

[0004] In summary, the existing interface passivation technology of perovskite solar cells is mainly based on organic materials, which has the problem of poor dispersion and has an adverse effect on cell efficiency. Summary of the invention

[0005] The purpose of the present invention is to provide a method for passivating the interface of a perovskite cell, so as to solve the technical problem that the interface passivation technology of the existing perovskite solar cell is mainly based on organic materials and has poor dispersibility. The present invention adopts ammonium polyphosphate to passivate the upper and lower interfaces of the perovskite, and the upper and lower interfaces of the perovskite solar cell have good dispersibility.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention discloses a perovskite battery interface passivation method, comprising the following steps: The nickel oxide solution is dropped onto the ITO substrate, and after being spin-coated evenly, it is dried to solidify the nickel oxide nanoparticle layer; Add the ammonium polyphosphate solution dropwise onto the solidified nickel oxide nanoparticle layer, spin-coat evenly, and then dry; The perovskite precursor solution is coated on the surface of the ammonium polyphosphate layer of the substrate by a two-step spin coating method, and annealed to complete the preparation of the perovskite layer; preparing an electron transport layer on the perovskite layer; A gold electrode was prepared on the electron transport layer.

[0007] Furthermore, the nickel oxide solution is dripped onto the ITO substrate, spin-coated evenly, and then dried to solidify the nickel oxide nanoparticle layer, as follows: The nickel oxide solution was dropped onto the cleaned ITO substrate and spin-coated at a speed of 2000 rpm to 6000 rpm for 15 s to 25 s; The spin-coated ITO substrate is placed in an environment of 100° C. to 150° C. and dried for 5 min to 20 min to solidify the nickel oxide nanoparticle layer and remove the solvent.

[0008] Furthermore, the concentration of the nickel oxide solution is 3 mg / ml to 15 mg / ml.

[0009] Furthermore, the ammonium polyphosphate solution is dripped onto the solidified nickel oxide nanoparticle layer, and the layer is evenly spin-coated and then dried, as follows: The ammonium polyphosphate solution was dropped onto the solidified nickel oxide nanoparticle layer and spin-coated at a speed of 3000 rpm to 8000 rpm for 20 s to 40 s; The ITO substrate after spin coating with ammonium polyphosphate is placed in an environment of 100° C. to 150° C. and dried for 5 min to 20 min to remove the solvent.

[0010] Furthermore, the concentration of the ammonium polyphosphate solution is 5 mg / ml.

[0011] Furthermore, the perovskite precursor solution is coated on the surface of the ammonium polyphosphate layer of the substrate by a two-step spin coating method, and annealed to complete the preparation of the perovskite layer, as follows: Spin-coat the perovskite precursor solution at 1000 rpm to 3000 rpm for 5 s to 15 s; Increase the speed to 4000 rpm~8000 rpm and spin-coat for 30s~50s, and add anti-solvent dropwise at 30s~40s; Anneal at 100°C~150°C for 20min~40min to complete the preparation of the perovskite layer.

[0012] Furthermore, the preparation process of the perovskite precursor solution is specifically as follows: FAI, MABr, CsI, PbBr2 and PbI2 powders were dissolved in a mixed solvent of DMF and DMSO, and 1%~5% PbI2 and 5%~40% MACl were added to obtain a perovskite precursor solution.

[0013] Furthermore, in the mixed solvent of DMF and DMSO, the volume ratio of DMF to DMSO is 4:0 to 4:1.

[0014] Furthermore, the electron transport layer is prepared on the perovskite layer, specifically as follows: An electron transport layer is prepared by evaporation on the perovskite layer, and the electron transport layer materials include C60 and PCBM.

[0015] Furthermore, the gold electrode is prepared on the electron transport layer, specifically as follows: Gold electrode was prepared by evaporation on the electron transport layer, and the evaporation rate of gold electrode was 1Ås -1 ~3Ås -1 , thickness is 60nm~120nm.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention drips a nickel oxide solution onto an ITO substrate, spin-coats the solution evenly, and then dries the solution to solidify the nickel oxide nanoparticle layer. The nickel oxide nanoparticle layer can provide a good electron transmission channel, which is beneficial to the improvement of battery performance. The ammonium polyphosphate solution is dripped onto the solidified nickel oxide nanoparticle layer, spin-coats the solution evenly, and then dries the solution. The ammonium polyphosphate layer may play a passivation role, reduce the interface defects between the nickel oxide layer and the perovskite layer, and improve the stability and efficiency of the battery. The perovskite precursor solution is applied to the surface of the ammonium polyphosphate layer of the substrate by a two-step spin coating method. The two-step spin coating method can avoid the aggregation and shrinkage problems of the one-step spin coating method, and obtain a very uniform and dense film. After the spin coating is completed, annealing is performed to complete the preparation of the perovskite layer. The annealing process helps the complete reaction of the perovskite precursor solution and the formation of crystals. Improving the quality of the perovskite layer is beneficial to improving the photoelectric conversion efficiency of the battery. Preparing an electron transport layer on the perovskite layer is beneficial to improving the photoelectric conversion efficiency and stability of the battery. A gold electrode is prepared on the electron transport layer. The present invention uses ammonium polyphosphate to passivate the upper and lower interfaces of perovskite. The phosphate groups on the lower interface are 2+ / Ni 3+ A strong coordination structure is formed, forming a stable buried interface. At the same time, during the annealing process of the perovskite layer, a small amount of ammonia is generated, which enhances the iodine vacancy formation energy and reduces the defect state of the lower interface of the film. The phosphate groups on the upper interface can react with the uncoordinated Pb 2+ Bonding reduces the defect states on the interface of the film, and the upper and lower interfaces of the perovskite solar cell have good dispersion.

[0017] 2. The present invention dissolves FAI, MABr, CsI, PbBr2 and PbI2 powders in a mixed solvent of DMF and DMSO. During the dissolution process, 1% to 5% of PbI2 is added as an additional iodine source, which helps to regulate the crystallization process of perovskite and improve the quality of the film. At the same time, 5% to 40% of MACl is added. The addition of MACl can inhibit the formation of undesirable phases, promote the vertical recrystallization of perovskite, and improve the crystallinity and stability of the perovskite film.

[0018] 3. The present invention prepares a gold electrode by evaporation on the electron transport layer, and the evaporation rate of the gold electrode is 1Ås -1~3Ås -1 , which helps to ensure the uniformity and density of the gold electrode and avoid film quality problems caused by too fast or too slow evaporation rates. The thickness is 60nm~120nm, which is convenient for providing good conductivity and mechanical stability while ensuring good contact between the gold electrode and the electron transport layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a flow chart of the method of the present invention; DETAILED DESCRIPTION In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0020] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0021] The present invention is further described in detail below in conjunction with the accompanying drawings: See also Figure 1 The present invention discloses a method for interface passivation of a perovskite battery, comprising the following steps: S1, drop the nickel oxide solution on the ITO substrate, spin-coat it evenly and then dry it to solidify the nickel oxide nanoparticle layer; the nickel oxide layer serves as a transition layer between the substrate and the subsequent layers, which helps to improve the interface properties between the substrate and the perovskite layer. The nickel oxide nanoparticle layer can provide a good electron transmission channel, which is beneficial to the improvement of battery performance.

[0022] S2, dropping the ammonium polyphosphate solution onto the solidified nickel oxide nanoparticle layer, spin coating it evenly and then drying it; the ammonium polyphosphate layer may play a passivation role, reduce the interface defects between the nickel oxide layer and the perovskite layer, and improve the stability and efficiency of the battery.

[0023] S3, the perovskite precursor solution is coated on the surface of the ammonium polyphosphate layer of the substrate by a two-step spin coating method. The two-step spin coating method can avoid the aggregation and shrinkage problems of the one-step spin coating method and obtain a very uniform and dense film. After the spin coating is completed, annealing is performed to complete the preparation of the perovskite layer. The annealing process helps the complete reaction of the perovskite precursor solution and the formation of crystals. Improving the quality of the perovskite layer is beneficial to improving the photoelectric conversion efficiency of the battery.

[0024] S4, preparing an electron transport layer on the perovskite layer, the electron transport layer helps to transfer electrons from the perovskite layer to the external circuit, reduces the recombination and loss of electrons at the interface, and improves the photoelectric conversion efficiency and stability of the battery.

[0025] S5, prepare a gold electrode on the electron transport layer. The gold electrode, as the negative electrode of the battery, provides a channel for collecting and transmitting electrons. The high conductivity and stability of gold help improve battery performance and long-term stable operation.

[0026] The present invention uses ammonium polyphosphate to passivate the upper and lower interfaces of perovskite. The phosphate groups on the lower interface are 2+ / Ni 3+ A strong coordination structure is formed, forming a stable buried interface. At the same time, during the annealing process of the perovskite layer, a small amount of ammonia is generated, which enhances the iodine vacancy formation energy and reduces the defect state of the lower interface of the film. The phosphate groups on the upper interface can react with the uncoordinated Pb 2+ Bonding reduces the defect states on the interface of the film, and the upper and lower interfaces of the perovskite solar cell have good dispersion.

[0027] Embodiment 1: See also Figure 1 The present invention discloses a method for interface passivation of a perovskite battery, comprising the following steps: S1, dropping the nickel oxide solution onto the ITO substrate, spin coating evenly and then drying to solidify the nickel oxide nanoparticle layer, as follows: The nickel oxide solution was dropped onto the cleaned ITO substrate and spin-coated at 2000 rpm for 15 s; The spin-coated ITO substrate was placed in an environment of 100° C. and dried for 5 minutes to solidify the nickel oxide nanoparticle layer and remove the solvent.

[0028] Preferably, the concentration of the nickel oxide solution is 3 mg / ml.

[0029] S2, dropping the ammonium polyphosphate solution onto the solidified nickel oxide nanoparticle layer, spin coating evenly and then drying, as follows: The ammonium polyphosphate solution was dropped onto the solidified nickel oxide nanoparticle layer and spin-coated at a speed of 3000 rpm for 20 seconds.

[0030] The ITO substrate after spin coating with ammonium polyphosphate was placed in a 100° C. environment and dried for 5 minutes to remove the solvent.

[0031] Preferably, the concentration of the ammonium polyphosphate solution is 5 mg / ml.

[0032] S3, coating the perovskite precursor solution on the surface of the ammonium polyphosphate layer of the substrate by a two-step spin coating method, annealing, and completing the preparation of the perovskite layer, as follows: The perovskite precursor solution was spin coated at 1000 rpm for 5 s; Increase the speed to 4000 rpm and spin-coat for 30 seconds, then add the anti-solvent dropwise at the 30th second; Annealing at 100 °C for 20 min completed the preparation of the perovskite layer.

[0033] Preferably, the preparation process of the perovskite precursor solution is as follows: The powders of FAI, MABr, CsI, PbBr2 and PbI2 were dissolved in a mixed solvent of DMF and DMSO, and 1% PbI2 and 5% MACl were added to obtain a perovskite precursor solution. The addition of 1% PbI2 as an additional iodine source was helpful to regulate the crystallization process of the perovskite and improve the film quality. At the same time, 5% MACl was added. The addition of MACl can inhibit the formation of undesirable phases, promote the vertical recrystallization of perovskite, and improve the crystallinity and stability of the perovskite film. Preferably, in the mixed solvent of DMF and DMSO, the volume ratio of DMF to DMSO is 4:0.

[0034] S4, preparing an electron transport layer on the perovskite layer, as follows: An electron transport layer is prepared by evaporation on the perovskite layer, and the electron transport layer materials include C60 (footballene) and PCBM.

[0035] S5, preparing a gold electrode on the electron transport layer, as follows: Gold electrode was prepared by evaporation on the electron transport layer, and the evaporation rate of gold electrode was 1Ås -1 , which helps ensure the uniformity and density of the gold electrode and avoid film quality problems caused by too fast or too slow evaporation rates. The thickness is 60nm, which is convenient for providing good conductivity and mechanical stability while ensuring good contact between the gold electrode and the electron transport layer.

[0036] Embodiment 2: See also Figure 1 The present invention discloses a method for interface passivation of a perovskite battery, comprising the following steps: S1, dropping the nickel oxide solution onto the ITO substrate, spin coating evenly and then drying to solidify the nickel oxide nanoparticle layer, as follows: The nickel oxide solution was dropped onto the cleaned ITO substrate and spin-coated at 4000 rpm for 20 s; The spin-coated ITO substrate was placed in an environment of 125° C. and dried for 12.5 min to solidify the nickel oxide nanoparticle layer and remove the solvent.

[0037] Preferably, the concentration of the nickel oxide solution is 9 mg / ml.

[0038] S2, dropping the ammonium polyphosphate solution onto the solidified nickel oxide nanoparticle layer, spin coating evenly and then drying, as follows: The ammonium polyphosphate solution was dropped onto the solidified nickel oxide nanoparticle layer and spin-coated at a speed of 5500 rpm for 30 s.

[0039] The ITO substrate after spin coating with ammonium polyphosphate was placed in a 125° C. environment and dried for 12.5 min to remove the solvent.

[0040] Preferably, the concentration of the ammonium polyphosphate solution is 5 mg / ml.

[0041] S3, coating the perovskite precursor solution on the surface of the ammonium polyphosphate layer of the substrate by a two-step spin coating method, annealing, and completing the preparation of the perovskite layer, as follows: The perovskite precursor solution was spin coated at 2000 rpm for 10 s; The rotation speed was increased to 6000 rpm and the coating was performed for 40 s. At the 35th s, the anti-solvent was added dropwise; Annealing at 125 °C for 30 min completed the preparation of the perovskite layer.

[0042] Preferably, the preparation process of the perovskite precursor solution is as follows: FAI, MABr, CsI, PbBr2 and PbI2 powders were dissolved in a mixed solvent of DMF and DMSO, and 3% PbI2 and 22.5% MACl were added to obtain a perovskite precursor solution. Adding 3% PbI2 as an additional iodine source helped to regulate the crystallization process of perovskite and improve the quality of the film. At the same time, adding 22.5% MACl could inhibit the formation of undesirable phases, promote the vertical recrystallization of perovskite, and improve the crystallinity and stability of the perovskite film.

[0043] Preferably, in the mixed solvent of DMF and DMSO, the volume ratio of DMF to DMSO is 4:0.5.

[0044] S4, preparing an electron transport layer on the perovskite layer, as follows: An electron transport layer is prepared by evaporation on the perovskite layer, and the electron transport layer materials include C60 (footballene) and PCBM.

[0045] S5, preparing a gold electrode on the electron transport layer, as follows: Gold electrode was prepared by evaporation on the electron transport layer, and the evaporation rate of gold electrode was 2Ås -1 , which helps to ensure the uniformity and density of the gold electrode and avoid film quality problems caused by too fast or too slow evaporation rates. The thickness is 90nm, which is convenient for providing good conductivity and mechanical stability while ensuring good contact between the gold electrode and the electron transport layer.

[0046] Embodiment three: See also Figure 1 The present invention discloses a method for interface passivation of a perovskite battery, comprising the following steps: S1, dropping the nickel oxide solution onto the ITO substrate, spin coating evenly and then drying to solidify the nickel oxide nanoparticle layer, as follows: The nickel oxide solution was dropped onto the cleaned ITO substrate and spin-coated at 6000 rpm for 25 s; The spin-coated ITO substrate was placed in an environment of 150° C. and dried for 20 minutes to solidify the nickel oxide nanoparticle layer and remove the solvent.

[0047] Preferably, the concentration of the nickel oxide solution is 15 mg / ml.

[0048] S2, dropping the ammonium polyphosphate solution onto the solidified nickel oxide nanoparticle layer, spin coating evenly and then drying, as follows: The ammonium polyphosphate solution was dropped onto the solidified nickel oxide nanoparticle layer and spin-coated at a speed of 8000 rpm for 40 seconds.

[0049] The ITO substrate after spin coating with ammonium polyphosphate was placed in a 150° C. environment and dried for 20 minutes to remove the solvent.

[0050] Preferably, the concentration of the ammonium polyphosphate solution is 5 mg / ml.

[0051] S3, coating the perovskite precursor solution on the surface of the ammonium polyphosphate layer of the substrate by a two-step spin coating method, annealing, and completing the preparation of the perovskite layer, as follows: The perovskite precursor solution was spin coated at 3000 rpm for 15 s; Increase the speed to 8000 rpm and spin-coat for 30s-50s, then add the anti-solvent at 40s; Annealing at 150 °C for 40 min completed the preparation of the perovskite layer.

[0052] Preferably, the preparation process of the perovskite precursor solution is as follows: FAI, MABr, CsI, PbBr2 and PbI2 powders were dissolved in a mixed solvent of DMF and DMSO, and 5% PbI2 and 40% MACl were added to obtain a perovskite precursor solution. During the dissolution process, 5% PbI2 was added as an additional iodine source, which helped to regulate the crystallization process of perovskite and improve the quality of the film. At the same time, 40% MACl was added. The addition of MACl can inhibit the formation of undesirable phases, promote the vertical recrystallization of perovskite, and improve the crystallinity and stability of the perovskite film.

[0053] Preferably, in the mixed solvent of DMF and DMSO, the volume ratio of DMF to DMSO is 4:1.

[0054] S4, preparing an electron transport layer on the perovskite layer, as follows: An electron transport layer is prepared by evaporation on the perovskite layer, and the electron transport layer materials include C60 (footballene) and PCBM.

[0055] S5, preparing a gold electrode on the electron transport layer, as follows: Gold electrode was prepared by evaporation on the electron transport layer, and the evaporation rate of gold electrode was 3Ås -1 , which helps to ensure the uniformity and density of the gold electrode and avoid film quality problems caused by too fast or too slow evaporation rates. The thickness is 120nm, which is convenient for providing good conductivity and mechanical stability while ensuring good contact between the gold electrode and the electron transport layer.

[0056] Embodiment 4: This embodiment discloses a method for passivating the interface of a perovskite battery. The method uses ammonium polyphosphate to passivate the upper and lower interfaces of the perovskite. The specific preparation process is as follows: S1、NiO x (NiO) nanoparticle layer preparation; Solution configuration: NiO x The nanoparticles are dispersed in water to prepare a 5 mg / ml nickel oxide solution, and the particles are evenly dispersed by ultrasonic treatment or mechanical stirring.

[0057] Spin coating process: Use a spin coater to drop the prepared nickel oxide solution onto the cleaned ITO (Indium Tin Oxides) substrate and spin coat at 4000 rpm for 20 seconds to ensure that NiO x Nanoparticles are evenly covered on the surface of the substrate. ITO substrate, that is, ITO conductive glass substrate, is made by coating a layer of indium tin oxide (ITO) film on the basis of soda-lime-based or silicon-boron-based substrate glass by magnetron sputtering.

[0058] Drying treatment: The spin-coated ITO substrate was placed in an oven at 120° C. for 10 min to solidify the NiOx nanoparticle layer and remove the solvent.

[0059] S2, passivation preparation; Solution preparation: Dissolve ammonium polyphosphate in pure water to prepare a 5 mg / ml ammonium polyphosphate solution.

[0060] Spin coating process: Also using a spin coater, drop the prepared ammonium polyphosphate solution onto the cured NiOx nanoparticle layer and spin coat at a speed of 5000 rpm for 30 seconds.

[0061] Drying treatment: The ITO substrate after spin coating with ammonium polyphosphate was placed in an oven at 120°C for 10 min to remove the solvent.

[0062] S3, preparation of subsequent layers; Perovskite layer: Perovskite layer adopts (FA 0.95 MA 0.05 ) 0.95 Cs 0.05 Pb(I 0.95 Br 0.05 )3, the band gap is 1.55eV, and the configuration method of the perovskite precursor solution is: The weighed FAI (formamidinium lead iodide), MABr (methylammonium bromide), CsI (cesium iodide), PbBr2 (lead bromide) and PbI2 (lead iodide) powders were dissolved in a mixed solvent of DMF (N,N-dimethylformamide) and DMSO (dimethyl sulfoxide). The concentration after dissolution was 1.0~2.0M, and the volume ratio of DMF and DMSO was 4:1. In addition, 3% PbI2 and 30% MACl were added to passivate grain boundary defects and promote crystal growth. During the dissolution process, the addition of PbI2 as an additional iodine source helps to regulate the crystallization process of perovskite and improve the quality of the film. At the same time, MACl is added. The addition of MACl can inhibit the formation of undesirable phases, promote the vertical recrystallization of perovskite, and improve the crystallinity and stability of the perovskite film.

[0063] The perovskite precursor solution was coated on the surface of the ITO substrate by a two-step spin coating method. The spin coating speed was 2000 rpm for 10 seconds and then increased to 5000 rpm for 40 seconds. The anti-solvent was added at 35 seconds, and then annealed at 100 ° C for 30 minutes to complete the preparation of the perovskite layer. Preparation of electron transport layer: The electron transport layer is prepared by evaporation on the perovskite layer. The electron transport layer materials include C60, PCBM, etc. to improve the electron transmission efficiency. The thickness of C60 is 30nm and the rate is 0.3Å s -1 ;preparation.

[0064] Preparation of electrode layer: Finally, a gold electrode was prepared by evaporation on the electron transport layer at a rate of 2Å s -1 , thickness is 100nm.

[0065] In summary, the present invention drips the nickel oxide solution onto the ITO substrate, spin-coats evenly and then dries, so that the nickel oxide nanoparticle layer is solidified. The nickel oxide nanoparticle layer can provide a good electron transmission channel, which is beneficial to the improvement of battery performance. The ammonium polyphosphate solution is dripped onto the solidified nickel oxide nanoparticle layer, spin-coats evenly and then dries; the ammonium polyphosphate layer may play a passivation role, reduce the interface defects between the nickel oxide layer and the perovskite layer, and improve the stability and efficiency of the battery. The perovskite precursor solution is coated on the surface of the ammonium polyphosphate layer of the substrate by a two-step spin coating method. The two-step spin coating method can avoid the aggregation and shrinkage problems of the one-step spin coating method, and obtain a very uniform and dense film. After the spin coating is completed, annealing is performed to complete the preparation of the perovskite layer. The annealing process helps the complete reaction of the perovskite precursor solution and the formation of crystals. Improving the quality of the perovskite layer is beneficial to improving the photoelectric conversion efficiency of the battery. Preparing an electron transport layer on the perovskite layer is beneficial to improving the photoelectric conversion efficiency and stability of the battery. A gold electrode is prepared on the electron transport layer. The present invention uses ammonium polyphosphate to passivate the upper and lower interfaces of perovskite. The phosphate groups on the lower interface form a strong coordination structure with Ni2+ / Ni3+ to form a stable buried interface. At the same time, during the annealing process of the perovskite layer, a small amount of ammonia is generated, which enhances the iodine vacancy formation energy and reduces the defect state of the lower interface of the film. The phosphate groups on the upper interface can bond with uncoordinated Pb2+, thereby reducing the defect state of the upper interface of the film. The upper and lower interfaces of the perovskite solar cell have good dispersion. See Table 1, which is a comparison table of performance parameters of existing perovskite solar cells and the perovskite cell of the present invention. The performance of the perovskite cell made by the method of the present invention is significantly improved.

[0066] Table 1 is a comparison table of performance parameters of existing perovskite solar cells and the perovskite solar cells of the present invention:

[0067] The key points of the method of the present invention using ammonium polyphosphate to passivate the upper and lower interfaces of perovskite are: The phosphate groups at the lower interface and Ni 2+ / Ni 3+ A strong coordination structure is formed, forming a stable buried interface. At the same time, during the annealing process of the perovskite layer, a small amount of ammonia is generated, which enhances the iodine vacancy formation energy and reduces the defect state of the interface under the film; The phosphate groups on the upper interface can interact with the uncoordinated Pb 2+ bonding, thereby reducing the defect states on the interface of the film.

[0068] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A perovskite battery interface passivation method, characterized in that: The following steps are involved: The nickel oxide solution is dropped onto the ITO substrate, and after being spin-coated evenly, it is dried to solidify the nickel oxide nanoparticle layer; Add the ammonium polyphosphate solution dropwise onto the solidified nickel oxide nanoparticle layer, spin-coat evenly, and then dry; The perovskite precursor solution is coated on the surface of the ammonium polyphosphate layer of the substrate by a two-step spin coating method, and annealed to complete the preparation of the perovskite layer; preparing an electron transport layer on the perovskite layer; A gold electrode was prepared on the electron transport layer.

2. A perovskite battery interface passivation method according to claim 1, characterized in that: The nickel oxide solution is dripped onto the ITO substrate, and after being evenly spin-coated, it is dried to solidify the nickel oxide nanoparticle layer, specifically as follows: The nickel oxide solution was dropped onto the cleaned ITO substrate and spin-coated at a speed of 2000 rpm to 6000 rpm for 15 s to 25 s; The spin-coated ITO substrate is placed in an environment of 100° C. to 150° C. and dried for 5 min to 20 min to solidify the nickel oxide nanoparticle layer and remove the solvent.

3. A perovskite battery interface passivation method according to claim 2, characterized in that: The concentration of the nickel oxide solution is 3 mg / ml to 15 mg / ml.

4. A perovskite battery interface passivation method according to claim 1, characterized in that: The ammonium polyphosphate solution is dropped onto the solidified nickel oxide nanoparticle layer, and the mixture is evenly spin-coated and then dried, as follows: The ammonium polyphosphate solution was dropped onto the solidified nickel oxide nanoparticle layer and spin-coated at a speed of 3000 rpm to 8000 rpm for 20 s to 40 s; The ITO substrate after spin coating with ammonium polyphosphate is placed in an environment of 100° C. to 150° C. and dried for 5 min to 20 min to remove the solvent.

5. A method for interface passivation of a perovskite battery according to claim 4, characterized in that: The concentration of the ammonium polyphosphate solution is 5 mg / ml.

6. A perovskite battery interface passivation method according to claim 1, characterized in that: The perovskite precursor solution is coated on the surface of the ammonium polyphosphate layer of the substrate by a two-step spin coating method, and annealed to complete the preparation of the perovskite layer, as follows: Spin-coat the perovskite precursor solution at 1000 rpm to 3000 rpm for 5 s to 15 s; Increase the speed to 4000 rpm~8000 rpm and spin-coat for 30s~50s, and add anti-solvent dropwise at 30s~40s; Anneal at 100°C~150°C for 20min~40min to complete the preparation of the perovskite layer.

7. A method for interface passivation of a perovskite battery according to claim 6, characterized in that: The preparation process of the perovskite precursor solution is specifically as follows: FAI, MABr, CsI, PbBr2 and PbI2 powders were dissolved in a mixed solvent of DMF and DMSO, and 1%~5% PbI2 and 5%~40% MACl were added to obtain a perovskite precursor solution.

8. A method for interface passivation of a perovskite battery according to claim 7, characterized in that: In the mixed solvent of DMF and DMSO, the volume ratio of DMF to DMSO is 4:0-4:

1.

9. A method for interface passivation of a perovskite battery according to claim 1, characterized in that: The electron transport layer is prepared on the perovskite layer, specifically as follows: An electron transport layer is prepared by evaporation on the perovskite layer, and the electron transport layer materials include C60 and PCBM.

10. A method for interface passivation of a perovskite battery according to claim 1, characterized in that: The gold electrode is prepared on the electron transport layer, specifically as follows: Gold electrode was prepared by evaporation on the electron transport layer, and the evaporation rate of gold electrode was 1Ås -1 ~3Ås -1 , thickness is 60nm~120nm.

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