LAUSR

Lead amine halide perovskite solar cells have been dominating photovoltaic research in this decade. The quality of the perovskite layer plays a significant role in the photovoltaic performance of planar perovskite devices, and solvent engineering is an effective method to improve the quality of the perovskite layer. Here, we introduce acetonitrile (ACN) as an effective solvent additive in the preparation of cation-anion-mixed perovskite of Cs0.05(MA0.17FA0.83)0.95Pb(I0.83Br0.17)3. The morphology observation indicates that a large grain, compact and pinhole-free perovskite layer is obtained by ACN adding. Steady-state and time-resolved photoluminescence measurements demonstrate fewer defects and less carrier recombination in the perovskite layer with ACN adding. The planar perovskite solar cell with ACN adding achieves a power conversion efficiency of 19.15% with slight hysteresis and stable output, while the device without ACN adding gets an efficiency of 17.47% under the same experiment conditions. The simple and green preparation process and the significant improvement of the device performance render this method promising.