Stable lead-free Te-based double perovskites with tunable band gaps: a first-principles study

Lead-free hybrid perovskites have attracted great attention as environmentally friendly light absorber layers. In this work, we report on Te-based double perovskites A2TeI6 (A = Tl, K, NH4, Rb, Cs, CH3NH3, and CH(NH2)2) as potential candidates for optoelectronic applications. The structural stability and electronic and optical properties of these Te-based double perovskite materials are investigated by using first-principles calculations. These Te-based double perovskites exhibit good structural stability, tunable band gap, and strong optical absorption. These Te-based double perovskites show promising optoelectronic properties, and may be potential candidates for photovoltaic applications. Our calculated results can provide a deep insight into developing lead-free perovskite solar cells.