Functionalized Interface For The Growth Of Perovskite CsPbI₃ And The Performance Of Solar Cell

All-inorganic perovskite CsPbI₃has become a research hotspot in perovskite solar cells due to its intrinsic chemical stability and prominent optoelectronic property.In recent years,CsPbI₃-based PSCs have achieved tremendous progress in power-conversion Efficiencies up to over 21%.However,most efficient devices are prepared in a humidity controlled and inert environment,limiting its industrialization development.Preparation of perovskite CsPbI₃solar cells in air and interface modification are important factors to improve device performance,and are also key to achieving industrialization.Therefore,this paper takes planar n-i-p structure CsPbI₃perovskite solar cells as the research object,uses functional interfaces to modify and regulate the growth of perovskite CsPbI₃crystals,and elaborates the microscopic mechanism in detail to solve the preparation conditions for high-quality and stable perovskite solar devices,which is expected to improve the PCE of solar photovoltaic devices.This paper is mainly concerned with the following:（1）The bottom interface of the device structure was designed.Nanoparticles with different concentrations of Mo doped Sn O₂were prepared by hydrothermal synthesis and dispersed into ethanol solvent to prepare the required colloidal solution for the bottom interface electron transport layer.The experimental results show that the bottom interface conical structure of doped Mo in Sn O₂nanocrystals provides a large number of nucleation sites for the growth of perovskite crystals,prepares CsPbI₃films with good crystallinity,strong charge extraction ability and high conductivity.For solar photovoltaic devices with short circuit current of 19.69 m A cm^-2and open circuit voltage of 1.11 V,PCE increased from 15.02%to 17.41%.（2）Top interface of the device layered structure was designed.We developed an effective curing-anti-solvent strategy combining green Me OAc anti-solvent and inorganic polymer perhydropolysilazane（PHPS）to prepare high-quality and stable black-phase CsPbI₃films in high-humidity air.Experimental and theoretical calculations show that PHPS will quickly hydrolyze in reaction with moisture in the air,forming a strong Lewis acid-based interaction toward the CsPbI₃precursor molecule（generated by hydrolyzed-Si（OH）₄-andPbI₂precursor molecule）,which can robustly shield the intrusion of ambient moisture and control grains growth.After annealing,the pyrolysis-generated Si-O-Si/Si-O-Pb bonding to CsPbI₃film further passivated surface defects,resulting in improved film quality.Under the ultra-wide processing window offered by PHPS curing,an extremely uniform and dense perovskite film enables the fabrication of PSCs with a remarkably improved PCE up to 19.17%in RH 60%,exhibiting excellent operational stability with 90%of the initial PCE retained after exposed in RH 30%for 1000 hours.