Direct formation of I3- ions in organic cation solution for efficient perovskite solar cells

This work presents an easy and controllable method for introducing I 3 - ions into organic cation dripping solution via chemical reaction of I - + I 2 → I 3 - $I^{-}+I_2\to {I_3}^{-}$ to effectively decrease the concentration of defects in organic-inorganic lead halide perovskite films. The perovskite solar cells based on additional I 3 - ions exhibited better photovoltaic performance , with a maximum power conversion efficiency of 18.7%, being about 15% higher than that of the control device. The elucidation of defects and its suppression by employing additional I 3 - ions provide an important direction for defects elimination and future enhancement of perovskite solar cells efficiency.