Beyond Perovskite Solar Cells: Tellurium Iodide as a Promising Light-Absorbing Material for Solution-Processed Photovoltaic Application.

Searching new light-absorbing materials to replace toxic lead halide in solar cells is very important and highly desirable. In this research, we firstly demonstrated that tellurium iodide (TeI4 ) could be used as a light-absorbing material in solar cells due to its suitable optical band gap and the active lone-pair electron orbital in Te4+ . The best power conversion efficiency (PCE=3.56%) was achieved with a concentration of 0.9 M TeI4 in DMF:DMSO (4 : 1, v,v) without any heat treatment or antisolvent dripping. Our study indicates the promising potential of TeI4 for photovoltaic and optoelectronic applications.