Lead‐free Perovskite Materials (NH4)3Sb2IxBr9−x

A family of perovskite light absorbers (NH4)3Sb2IxBr9−x (0≤x≤9) was prepared. These materials show good solubility in ethanol, a low‐cost, hypotoxic, and environmentally friendly solvent. The light absorption of (NH4)3Sb2IxBr9−x films can be tuned by adjusting I and Br content. The absorption onset for (NH4)3Sb2IxBr9−x films changes from 558 nm to 453 nm as x changes from 9 to 0. (NH4)3Sb2I9 single crystals were prepared, exhibiting a hole mobility of 4.8 cm2 V−1 s−1 and an electron mobility of 12.3 cm2 V−1 s−1. (NH4)3Sb2I9 solar cells gave an open‐circuit voltage of 1.03 V and a power conversion efficiency of 0.51 %. Unleaded: Lead‐free perovskite materials (NH4)3Sb2IxBr9−x (0≤x≤9) were developed by using ethanol as the solvent. (NH4)3Sb2I9 single crystals were prepared and the crystal structure was analyzed. Solar cells were made by using (NH4)3Sb2IxBr9−x as the light absorbers. (NH4)3Sb2I9 solar cells gave a high open‐circuit voltage of 1.03 V and a power conversion efficiency of 0.51 %.