Research On The Interface And Light-absorbing Layer Of MAPbI₃ Perovskite Solar Cell

In recent years,organic metal-halogenated perovskite solar cells have attracted more and more researchers because of their low defect,excellent photoelectric properties,high extinction coefficient,long carrier diffusion distance,and bipolar transmission characteristics.its power conversion efficiency（PCE）has soared from 3.8%to 22.7%in only a few years.However,if perovskite solar cells are to be used in industry,they still need to overcome several difficulties:poor stability,high toxicity of lead material,and large-area preparation.In this dissertation,we mainly focuse on improving the potonto electicity conversion efficiency and environmental stability of the solar cell by modifying the TiO₂ electron transport of the MAPbI₃ perovskite cell and doping the perovskite absorbing layer.The study results are shown as below:1、The first part proposes the surface modification of an-TiO₂ electron transport layer using a new type low defect density polymer ITIC.The polymer’s inherently low defect density and semiconductor properties can produce synergistic effects with TiO₂,which can improve the conductivity of the TiO₂ electron transport layer,reduced contact resistance,surface,defects and a well-matched work function.This method increases the efficiency of the planar perovskite solar cell from 17.12%to 20.08%.2.In the second part,some polymers were selectively doped into MAPbI₃ perovskite films,including p-type n-type semiconductors and typical insulators（J50,J51,J61,J71,N2200 and PMMA）.The doping of the long-chain polymer at a suitable concentration helps the perovskite crystal particles form network structure,thereby effectively improves the morphology and humidity stability of the perovskite film.The efficiency of the solar cell increases from 17.43%to 19.19%,and it also has good.It does not need to have a strict energy level match with perovskite.Therefore,these polymers can be used in such photoelectric devices.3.In the third part,we proposed a new method using CsPbCl3 quantum dot solution,spin coating it between titanium dioxide and FA_0.85MA_0.15PbI_2.55Br_0.45 perovskite film,which grows in the perovskite film.This promotes the formation of PbI₂ at grain boundaries and can effectively passivate defect:at elevated temperatures,Cl-is exposed to MA+ through the formation of MACl at the grain boundaries and is easily sublimated,which is accompanied by the formation of PbI₂.This method only affects the formation of the perovskite component and has little effect on its morphology of the perovskite film.Studies have shown that moderate distribution of PbI₂ at grain boundaries reduces the density of defect states,increases the photoluminescence intensity and the carrier lifetime of the perovskite thin film.By optimizing,the high efficiency of 20.09%and stable perovskite solar cell is obtained,the cell has no hysteresis.