Mixed Halide CH3 NH3 PbI3 x Xx (X=Cl, Br, I) Perovskites: Vapor Assisted Solution Deposition and Application as Solar Cell Absorbers.
There have been recent reports on the formation of single halide perovskites, CH3 NH3 PbX3 (X=Cl, Br, I) by means of vapor assisted solution processing. Herein, the successful formation of mixed halide perovskites (CH3 NH3 PbI3 x Xx by means of a vapor assisted solution method at ambient atmosphere is reported. The perovskite films are synthesized by exposing PbI2 film to CH3 NH3 X (X=I, Br, or Cl) vapor. The prepared perovskite films have uniform surfaces with good coverage, as confirmed by SEM images. The inclusion of chlorine and bromine into the structure leads to a lower temperature and shorter reaction time for optimum perovskite film formation. In the case of CH3 NH3 PbI3 x Clx the optimum reaction temperature is reduced to 100 degC, and the resulting phases are CH3 NH3 PbI3 (with trace Cl) and CH3 NH3 PbCl3 with a ratio of about 2:1. In the case of CH3 NH3 PbI3 x Brx single phase CH3 NH3 PbI2 Br is formed in a considerably shorter reaction time than that of CH3 NH3 PbI3 The mesostructured perovskite solar cells based on CH3 NH3 PbI3 films show the best optimal power conversion efficiency of 13.5 whereas for CH3 NH3 PbI3 x Clx and CH3 NH3 PbI3 x Brx the best recorded efficiencies are 11.6 and 10.5 respectively.
Chemphyschem a European journal of chemical physics and physical chemistry