Preparation And Performance Of Inverted Perovskite Solar Cell Based On Magnetron Sputtered NiO_x Hole Transport Layer

Organic-inorganic hybrid perovskite solar cells(Perovskite Solar Cells,PSCs)have received extensive attention in recent years due to their high power conversion efficiency,abundant raw materials and simple manufacturing process.NiO_x is often used as a hole transport material in the production of inverted planar PSCs due to its superior carrier transport properties,excellent chemical stability and low cost.The magnetron sputtering method is a method that can realize the large-area preparation of NiO_x films.The prepared NiO_x film has a uniform surface and high flatness,but the conductivity of the film is low and there is a significant oxidation-reduction reaction at the interface of the perovskite layer.Therefore,the performance of sputtered NiO_x-based PSCs is generally weaker than that of solution-based NiO_x-based PSCs.In this paper,to solve the low carrier mobility of NiO_x(sp-NiO_x)films prepared by sputtering method,a small amount of O₂ is added during the preparation of NiO_x by magnetron sputtering to improve the hole transport performance of the film;Aiming at the phenomenon that the redox reaction between sp-NiO_x and the perovskite layer causes the performance of the device to be weakened,the interface is adjusted by adding excessive FAI and reducing the proportion of PbI₂;finally,considering the inherent characteristics of the common electrode transparent electrode ITO Mechanical brittleness is not suitable for the problem of flexible PSCs.We applied AZO/Ag O_x/AZO multilayer electrodes prepared by magnetron sputtering instead of ITO to PSCs,and optimized NiO_x as the hole transport layer,and developed the structure as AZO/Ag O_x/AZO/NiO_x/Per/PCBM/BCP/Ag battery devices.The main content and innovative results of the paper are as follows:(1)The NiO_x film was prepared by magnetron sputtering,and the influence of O₂ gas flow ratio during the sputtering process on the performance of NiO_x film and PSCs based on it was studied.The results show that the incorporation of a proper amount of O₂ can increase the proportion of Ni³⁺in the NiO_x film,and significantly improve the hole extraction and transport performance of NiO_x,it can also increase the size of the perovskite grains grown on it and enhance the crystallization performance.By optimizing the oxygen/argon gas flow ratio,it is found that the PSCs prepared when the O₂ and Ar flow rates are 1 sccm and 50 sccm,respectively,have the best performance,and their power conversion efficiency(PCE)can reach 12.48%.(2)Aiming at the phenomenon that sp-NiO_x reacts easily with the A-site cation of the perovskite,which leads to the weakening of the battery device performance,we have studied the control of the NiO_x/perovskite interface reaction through the perovskite precursor component engineering to achieve Technology for improving the performance of PSCs.Two schemes were specifically explored:(1)appropriately increase the proportion of FAI in the perovskite precursor solution;(2)appropriately reduce the proportion of PbI₂ in the perovskite precursor solution.The test results show that both methods can effectively improve the crystalline quality and surface morphology of the perovskite layer on sp-NiO_x,and significantly enhance the photovoltaic performance of the device.After parameter optimization,it is found that the PSCs prepared with an excess of 2%FAI have the highest photoelectric conversion efficiency of 13.44%;when the PbI₂ is reduced by 2%,the highest PCE is 14.14%.In comparison,the effect of directly reducing the proportion of PbI₂ is better.(3)In order to explore the application of sp-NiO_x-based PSCs in the field of flexible batteries,an AZO/Ag O_x/AZO multilayer electrode was prepared.This electrode has transparent conductivity comparable to ITO(The average transmittance of AZO/Ag O_x/AZO deposited on the glass substrate and the PET substrate in the visible light range is 74.74%and73.36%,respectively,and the sheet resistance is 8.55?/sq and 8.37?/sq,respectively),and the flexibility is excellent.After 10,000 times of bending under a bending radius of 10 mm,it can still maintain a sheet resistance of 10.12?/sq.Using the prepared AZO/Ag O_x/AZO multilayer electrode instead of ITO,it was applied to sp-NiO_x-based PSCs,and the device on the glass substrate obtained a PCE of 10.15%,while the device efficiency on the flexible PET substrate was 8.05%.After 2500 bending tests,the flexible PSCs still maintains 85% of the initial efficiency.