Organic‐free indium‐doped cesium lead iodide perovskite for solar cell application

Herein, organic‐free all‐solid‐state based perovskite solar cells (PSCs) are successfully fabricated by one‐step method. The absorption position of the non‐perovskite cesium lead iodide (δ‐CsPbI ₃ ) was significantly shifted towards longer wavelength side by substituting indium (In) ion with different stoichiometric ratio. The authors demonstrated a facile route to achieve high efficiency by the fabrication of room temperature stable mixed‐phase CsPbI ₃ perovskite. Photovoltaic efficiency of doped perovskite is four times increased compared to pure yellow phase CsPbI ₃ . To the best of the authors’ knowledge, this is the first demonstration of In‐doped‐CsPbI ₃ based PSCs, which was fabricated under completely open‐air atmosphere.