Research On Performance Of Solar Cell Devices Based On Modified Perovskite Materials

Perovskite solar cells based on organometal halide light absorbers have been considered a promising photovoltaic technology due to their superb power conversion efficiency?PCE?along with very low material costs.Since the first report on a long-term durable solid-state perovskite solar cell with a PCE of 9.7%in 2012,a PCE as high as 19.3%was demonstrated in 2014,and a certified PCE of 17.9%was shown in 2014,and the certified efficiency of the perovskite device has more than 22%in 2016.Such a high photovoltaic performance is attributed to optically high absorption characteristics and balanced charge transport properties with long diffusion lengths.Formamidinium lead triiodide?HC?NH2?2PbI3 or FAPbI3?and MAPbX3 is gaining increasing interest in the field of perovskite solar cells?PSCs?.Because of its broader light absorption compared with the CH₃NH₃PbI3?MAPbI3?.and Cl-instead of I-ions can reduce the crystallization rate of perovskite,improve the control of the perovskite crystal,further improve the surface crystallinity.But FAPbI3 has two polymorphs?"black" perovskite ?-FAPbI3 and "yellow" non-perovskite ?-FAPbl3?at ambient temperature.It becomes particularly important to suppress the formation of the non-perovskite ?-FAPbI3 for achieving high efficiency in FAPbI3-base PSCs.In this study,we demonstrate that mixed-organic-cation can suppress the formation of?-FAPbI3 and forms "black" ?-FAPbI3 perovskite phase.Then we reduce the annealing temperature,further improve the photoelectric conversion efficiency of perovskite solar cells.This paper is divided mainly into two parts:?1?In this paper,based on ITO/PEDOT:PSS/perovskite/PCBM/Aluminum plane heterojunction structure,optimizes the influence factors,for example,annealing temperature,selection of the environment and extracting solvent,dispensing time,in the perovskite membrane preparation process,for two different modified perovskite material devices respectively.The average photoelectric conversion efficiencies of the optimized devices are 9.1%and 8.7%.Building further on this foundation,MAI and FAI are mixed to be made of perovskite devices.The average efficiency of the final optimized device is 14.0%,and the efficiency of the optimal device is 14.8%.?2?The study of the influence of annealing temperature on the mixing cationic perovskite device.Perovskite membrane is tested via a series of methods,for example,x-ray diffract meter?XRD?,scanning electron microscopy?SEM?,ultraviolet/visible light/near infrared radiation absorptive spectrometer and so on.This article demonstrates that perovskite crystal can be completely promoted for the mixing cationic perovskite at annealing temperature of 100 degrees.This article also draws a conclusion that it makes perovskite crystallization easier,preparation of perovskite membrane surface smoother and crystal particles larger than that at annealing temperature of 150 degrees in the literature.