Synthesis of Hybrid Tin Halide Perovskite Solar Cells with Less Hazardous Solvents: Methanol and 1,4‐Dioxane

Abstract

The toxicity of lead and the solvents utilized during the synthesis of hybrid halide perovskite films are potential obstacles for widespread applications of solar cell technology based on these materials. Alternatives such as those based on lead‐free Sn‐based devices often suffer from poor film morphologies, thus precluding competitive device efficiencies. Herein, we demonstrate a new one‐step route deploying mixtures of the less hazardous methanol and 1,4‐dioxane for preparing high‐quality methylammonium tin iodide films. We propose that the fast evaporation of these solvents is a key factor for film formation and show that the solvent ratio is essential to obtain phase pure, high‐quality films. This leads to devices, which outperform those prepared by conventional routes, likely due to a decreased defect density as confirmed with time‐resolved photoluminescence measurements. Our results provide a further step towards non‐hazardous synthesis routes for Sn‐based optoelectronic devices.