Bi3+-doped CH3NH3PbI3: Red-shifting absorption edge and longer charge carrier lifetime

Abstract Ion doping is an effective approach to improve the properties of hybrid perovskite CH 3 NH 3 PbI 3 , such as chemical stability and solar absorption. Here Bi 3+ -doped CH 3 NH 3 PbI 3 was synthesized via cooling crystallization process in aqueous solution. Along with the Bi 3+ doping, the bandgap of CH 3 NH 3 PbI 3 could be significantly narrowed, by the maximum value of 140 meV at the optimal doping level of 1.6 M %. Transient photovoltage measurement (TPV) revealed the Bi 3+ -doped CH 3 NH 3 PbI 3 could achieve a charge carrier lifetime of 280 μs, which was almost twice longer than that of pristine CH 3 NH 3 PbI 3 (157 μs). The prolonged carrier lifetime of Bi 3+ -doped CH 3 NH 3 PbI 3 was supposed to be attributed to its lower packing factor (PF), which was caused by the CH 3 NH 3 + vacancy (V MA ) after doping This work provides a new approach to tune the band gap and charge carrier lifetime of the hybrid perovskite CH 3 NH 3 PbI 3 , which should be promising to further improve the performance of perovskite-based photovoltaic devices.