Introducing lead acetate into stoichiometric perovskite lewis acid-base precursor for improved solar cell photovoltaic performance

Recently, numerous efforts have been reported on improving the properties of perovskite absorber, which has a direct and significant influence on the photovoltaic performance of solar cells. In this paper, lead acetate was introduced into stoichiometric lewis acid-base perovskite precursor to prepare high-quality methylammonium lead halide (MAPbI3) perovskite films. The trace lead acetate can facilitate the perovskite crystallization and induce grain size growth. After introducing lead acetate, the perovskite films show higher photoluminescence intensity and longer carrier lifetime due to less traps and defects, which is attributed to the improved film properties. The impedance spectroscopy measurements reveal that the lead acetate can decrease the series resistance and recombination resistance in the perovskite solar cells. As a result, the perovskite solar cells with lead acetate achieve an improved average efficiency of 18.06% (18.86% of best efficiency) compared with 16.87% of average efficiency of the control samples without lead acetate, while the hysteresis behavior is also significantly suppressed with the lead acetate.