Interface Modification And Properties Of The All-inorganic Perovskite CsPbX₃

The highest certified power conversion efficiency of the organic-inorganic hybrid perovskite solar cells has exceeded 25%,becoming the most promising next-generation solar cell.Unfortunately,the organic component in the perovskite material is volatile,making it decomposable at high temperature,which affects the long-time stability of perovskite solar cells.All inorganic perovskite materials can fundamentally solve this problem due to their superior stability,which have been attracted widely attention in recent years.In this thesis,inorganic CsPbI2Br and CsPbX3 perovskite cells have been optimized by the interfacial engineering,solvent engineering and hole-transport material optimization,so as to improve the photovoltaic performance of the corresponding solar cells.The main contents of this thesis are as follows:Inorganic CsPbI2Br perovskite cell with excellent performance was prepared by introducing C101 dye at the perovskite/hole transport layer interface.It is found that C101 dye modification can effectively inhibit the nonradiative recombination and reduce the defect density of the CsPbI2Br perovskite film.On the other hand,it can drive the hole transport,accelerate the hole extraction rate,and improve the photovoltaic performance of the device.Compared with the control device,the power conversion efficiency of the optimized CsPbI2Br perovskite cell can be improved to 14.96%,in which the short-circuit current density increased from 14.74 mAcm-2 to 15.84 mAcm-2,and the fill factor increased from 73.10%to 82.03%.The efficiency of the optimized perovskite cell can maintain 92%of the initial efficiency after it is placed in the environment with 30%humidity for 32 days,which indicates that the introduction of C101 is beneficial to the long-time air stability of the device due to its passivation effect.The effects of different ratio of DMF and DMSO in the precursor solution on the morphology of CsPbI3 perovskite film and the performance of the perovskite cell were investigated in detail.It was found that due to the premature volatilization of the intermediate formed by DMSO and Pb2+,the hydrolysis of DMF to(CH3)2NH2I coded as DMAI under acid atomosphere will enhance the better crystallinity of the film and the better performance of the perovskite cell.In particular,16.20%power conversion efficiency and good stability of CsPbI3 perovskite cell device were obtained by using pure DMF as solvent.Four kinds of PTAA with different polymerization degree were used as holetransport materials to prepare highly efficient CsPbI3 perovskite solar cells by optimizing the solution concentration.Finally,a power conversion efficiency of 16.40%was obtained.It was found that the surface roughness of CsPbI3 perovskite film and the conductivity of PTAA were significantly improved with the broadening of the molecular weight range and the increasing of the molecular weight of PTAA.The photovoltaic performance of CsPbI3 perovskite cell was improved as well.