Modulation of Charge Recombination in CsPbBr_3 Perovskite Films with Electrochemical Bias

摘要

The charging of a mesoscopic TiO_(2) layer in a metal halide perovskite solar cell can influence the overall power conversion efficiency. By employing CsPbBr_(3) films deposited on a mesoscopic TiO_(2) film, we have succeeded in probing the influence of electrochemical bias on the charge carrier recombination process. The transient absorption spectroscopy experiments conducted at different applied potentials indicate a decrease in the charge carrier lifetimes of CsPbBr_(3) as we increase the potential from −0.6 to +0.6 V vs Ag/AgCl. The charge carrier lifetime increased upon reversing the applied bias, thus indicating the reversibility of the photoresponse to charging effects. The ultrafast spectroelectrochemical experiments described here offer a convenient approach to probe the charging effects in perovskite solar cells.