NaI Doping Effect on Photophysical Properties of Organic-Lead-Halide Perovskite Thin Films by Using Solution Process

Perovskite solar cells (PSCs) have been developed rapidly in recent years. How to modify the photophysical properties of perovskite films has become the critical issue, affecting device performance. In this paper, NaI doping into the perovskite layer is attempted to modulate the photophysical properties to improve the performance of PSCs. The perovskite layer was prepared by using the one-step solution spin coating method with doping different concentrations of NaI into the perovskite precursor solution and chlorobenzene employed as the antisolvent. Experimental results show that the absorption band edge and the peak position of the PL spectrum of the doped perovskite thin film were red shifted; thus, the band gap of the semiconductor film became narrow. Doping NaI into perovskite is an effective way, by which the photophysical properties of perovskite films are well modified, thus improving device performance.