Solvent-controlled growth of inorganic perovskite films in dry environment for efficient and stable solar cells

TLDR

Inorganic halide perovskites such as CsPbI₃ offer excellent thermal stability and a 1.73‑eV bandgap suitable for tandem cells, yet their phase instability limits device optimization. Solvent‑controlled growth in a dry environment yields high‑quality, stable α‑phase CsPbI₃ films, enabling 15.7 % efficient solar cells that remain stable for over 500 h of continuous light soaking.

Abstract

Abstract Inorganic halide perovskites such as cesium lead halide are promising due to their excellent thermal stability. Cesium lead iodide (CsPbI 3 ) has a bandgap of 1.73 eV and is very suitable for making efficient tandem solar cells, either with low-bandgap perovskite or silicon. However, the phase instability of CsPbI 3 is hindering the further optimization of device performance. Here, we show that high quality and stable α-phase CsPbI 3 film is obtained via solvent-controlled growth of the precursor film in a dry environment. A 15.7% power conversion efficiency of CsPbI 3 solar cells is achieved, which is the highest efficiency reported for inorganic perovskite solar cells up to now. And more importantly, the devices can tolerate continuous light soaking for more than 500 h without efficiency drop.