Effect Of Interface Modification On Perovskite Solar Cell Performance

Solar energy is the most abundant resource all around the world.With the problems of pollution and resource shortage becoming more and more acute,solar energy has been widely advocated as a kind of green energy.Perovskite solar cells have gained extensive attention for its high efficiency,low cost,simple craft and potential application in flexible devices.To enhance power conversion efficiency(PCE),some methods have been developed,including compounding new perovskite materials,controlling the morphology of perovskite film,improving the crystallinity of perovskite film and modifying electron and hole transport layer.In this work,we investigate the effect of TiOx electron transport layer modification on the microstructure of perovskite films and the device performance of solar cells with perovskite active layer fabricated via one-step method.The specific contents are as following:(1)The perovskite film fabricated by normal one-step method is fairly rough and defective.In order to reduce the defects and improve the morphology of perovskite active layer,diluted MAI solution,MABr solution and PbI2 solution are used to pretreat TiO2 film before spin-coating precursor solution,and the device performance is improved.We tested SEM images,IV curves,steady state photocurrent,steady state efficiency,EQE and stability of the solar cells with perovskite active layers on pretreated TiO2.Our results indicate that pretreated devices have better performance than control devices.MABr pretreated device show better device performance and less hysteresis among pretreated devices.(2)Ethyl acetate(EA)is a kind of solvent that has lower boiling point than chlorobenzene(CB).Besides,EA is more environmentally friendly than cholrbenzene.To investigate the effect produced by different anti-solvents on perovskite films,we used the mixture of EA and CB with different ratio as the anti-solvent to fabricate the perovskite active layer and compare the difference in the device performance for the devices based on the perovskite films treated with the mixture of EA and CB with different ratio.Our shows that the devices developed from mixed anti-solvent treated perovskite films exhibit better characteristics than that of control devices.