Preparation Of Organic/Inorganic Perovskite Films By Rapid Annealing And Its Performance Researchrch

In recent years,organic-inorganic hybrid perovskite solar cells have drawn much attention because of its high efficiency,easy fabrication,low cost,earth abundance and others advantages.Inorganic-organic hybrid perovskite solar cells(PSCs)have reached from 3.8%in 2009 to a recently certified 22.1%.In order to further improve the efficiency of the device,on the one hand,larger particles and smooth absorption thin films are needed;on the other hand,a wide range of absorption spectra is important for perovskite films.Nanoscale tiny grains of perovskite are rapid self-assembled in the coating process.The growth direction of grain nucleation is hard to control,hence leading to defective perovskite films.The low uniform of the thin film thus result in the consequently electron-hole recombination and short carrier diffusion distance.In this work,the absorption layers of perovskite solar cells were prepared by one step solution method.By adjusting the ratio of PbI2 and CH3NH3I precursor solutions and different spin coating processes,the preparation conditions of the films with good properties were investigated,and the factors influencing the formation of perovskite films were analyzed.Combined with conventional device structure(ITO/PEDOT:PSS/CH3NH3Pbl3/PCBM/Bphen/Ag),perovskite solar cells were prepared to study the influence of different annealing processes on cell performance.After analysis of the materials by XRD,SEM,UV Vis absorption and I-V test,the main conclusions are as follows.1.Decreasing annealing pressure can accelerate the formation of MAPbI3 and lead to better orientation growth.With the increase of annealing pressure,the grain size becomes larger and the grain boundary becomes obvious.With the increase of the pressure,the performance parameters of the device increase first and then decrease.When the pressure is 4 Torr,the maximum value is reached,and the photocurrent density is the maximum.2.The absorption peak of the absorption layers were red shifted with the increase of annealing pressure,and the films under vacuum are less decomposed and more uniform and denser than those under vacuum and atmospheric pressure.3.The existence of a small amount of PbI2 and the increase of impurity and defect density will promote the crystallization of crystals,optimize the morphology of perovskite layers deposits,but also affect the efficiency of devices.4.Annealing in fast annealing furnace can shorten the preparation time of perovskite films,and the fluorescence peak of the perovskite films have a certain degree of red shift.5.The decrease of annealing pressure can reduce the exciton recombination and decrease the photoluminescence effect.The performance of the films can be improved by changing the annealing pressure and the performance of the devices can be improved.