Preparation And Interface Passivation Of Inverted Perovskite Solar Cells Based On NiO_x Hole Transport Layer

Since the advent of perovskite solar cells,it has provided new ways for the use of clean energy.Among them,the inverted perovskite solar cells facilitate the development of laminated structure perovskite cells and flexible substrate cells,which have attracted wide attention.In inverted perovskite solar cells,the preparation of high-quality perovskite absorber films and efficient carrier transport between interfaces are critical to improving the performance of perovskite solar cells.Adjusting the preparation process of the perovskite solar cell thin film and adding additives to modify the internal defects of the crystal and the interface defects are considered to be an effective way to reduce the recombination of carriers between the interfaces and improve the efficiency of carrier transport.Therefore,this article mainly focuses on the preparation process of perovskite solar cell thin film,the interface modification of the transport layer,and the passivation of internal defects of the crystal.First,this article discusses the concentration of the precursor solution,the spin coating speed,and the PCBM concentration of the electron transport layer.The optimal preparation parameters were determined.the concentration of the precursor solution of1.3 M,the rotation speed of 5000 rpm,and the concentration of the electron transport layer of 10 mg/m L.The average conversion efficiency of the device after optimization is 16.51%.The role of chloride ions in the precursor solution is discussed,and it is found that the presence of chloride ions can induce the crystallization of perovskite crystals.And use a precursor solution without chloride ion doping to try to prepare perovskite solar cells on flexible substrate.Finally,a flexible perovskite solar cell with an energy conversion efficiency of 13.10%and a fill factor of 49.76%is obtained,which improves the application scenarios of perovskite solar cells.Secondly,different concentrations of PTAA were used to modify the surface of Ni O_X film,and the effects of PTAA modification on film transmittance,film roughness,and perovskite crystallization were studied respectively.As the concentration of PTAA increases in the visible light range of 400-800 nm wavelength,the average transmittance also gradually increases.The roughness of the perovskite film is reduced,and the perovskite crystallinity is better.The carrier transport between the interfaces has been significantly improved.Corresponding devices were prepared based on different concentrations of PTAA.When the PTAA concentration was 4 mg/m L,the best energy conversion efficiency was 18.50%,and the fill factor was 73.9%.Finally,the ionic liquid BMIMBF₄with different volume ratios is used as the additive of the precursor solution to realize the passivation of the internal defects of the crystal.The effects of different additions on the crystallization of perovskite thin films were studied,the effects on carrier transport were analyzed,and corresponding devices were fabricated.Experiments have found that when the additive volume ratio is 1%,compared with the reference device,the perovskite film has reduced pinholes and defects,and improved carrier transport between interfaces.The fill factor is increased from 72.12%to 75.61%.The energy conversion efficiency increased from 16.06%to16.91%.When the volume ratio of the ionic liquid additive is 2%,the perovskite grain size decreases,the surface roughness of the perovskite film increases,and the film surface becomes uneven again.The grain boundary inside the film increases.The energy conversion efficiency is 15.89%.The fill factor is reduced to 71.06%.