Application Of Interfacial Doping Method In Perovskite Solar Cells

Perovskite solar cell is a highly efficient thin film photovoltaic device with the advantage of adjustable spectral response range and solution-processable developing in recent years.It becomes the research hotspot in the field of photovoltaic.The high quality perovskite solar cells depend on the effective modification of the light harvester layer.This paper adopts the interface modification doping method improving the light absorption performance of HC?NH₂?₂PbI₃ and CsPbI₃.The specific research contents are as follows:1,For the peroskite solar cells with formamidinium lead iodide as light harvester,univalent cation doping is usually necessary for stabilizing the perovskite crystal structure of formamidinium lead iodide.Cesium ions can be used for eliminate the tension of crystal lattice,and it substantially improves the stability and photovoltaic performance.In this work,we produce cesium doped formamidinium lead iodide by interfacial doping method,which is different from the mixed solution doping method in previous reports.Element analysis indicates that cesium dopant cannot be detected at the outer surface of perovskite layers by interfacial doping method,and the majority of cesium dopants should locate at the vicinity of TiO₂/perovskite interfaces,which is remarkably different from the cesium distribution in the perovskite layers by mixed solution doping method.The interfacial doping method can avoid the blue shift of light absorption edge by the incorporation of cesium ions,and their performance is depended on the quantity of dopants.For the optimized condition,formamidinium perovskite solar cells by interfacial doping have apower conversion efficiency of 17.1%,which is better than the power conversion efficiency of devices without cesium doping and with cesium doping by conventional mixed solution method.2,Reports have said that the two-dimensional perovskite material diethyl ammonia perovskite?EDAPbI₄?and three-dimensional perovskite material CsPbI₃ make up 2D/3D mixed perovskite material,effectively increasing the size of perovskite crystal grain,improving the conversion efficiency of solar cells as well.Interface engineering method is an accepted method that can improve the performance of perovskite solar cells.In this experiment,we introduce the EDAPb I₄ as a interfacial doping layer between electronic transport layer and light absorption layer and obtain local mixed 2D/3D perovskite layer.In addition we fabricate the planar junction perovskite solar cell based on this method.By adjusting the concentration of EDAPbI₄,device efficiency is improved clearly.