Perovskite Films Doped with Polyoxometalate and Ionic Liquid Assisted Crystallization for Efficient Photodetectors

Abstract

The dependence of perovskite-based photovoltaic devices on toxic solvents limits their applications. Therefore, we added polyoxometalates into ionic liquids, as the green solvent and polyoxometalates synergistically improve the performance of devices. Firstly, methylammonium formate (MAFa) as solvent delayed the crystallization process of perovskite thin films, thus obtained an extended crystal domain, and the photocurrent of the device was increased from 35.51 μA to 63.18 μA. Secondly, introducing PW 12 into this green solvent system, the matched energy level and good electron transmission rate promoted the separation of photogenerated excitons and accelerated the transmission of photogenerated electrons in perovskite. After dual adjustment of MAFa and PW 12 , the photocurrent of the champion device reached 95.99 μA (about 2.7 times of the original device), the unpacked devices can still maintain 80 % of initial value after being placed under environmental conditions for 700 h.