Gas‐Quenching Approach for Fabricating Cs 2 AgBiBr 6 Thin Films in Ambient Environment for Lead‐Free All‐Inorganic Perovskite Solar Cells with Carbon Electrodes

Herein, Cs 2 AgBiBr 6 double perovskite films, which is considered one of the alternative materials to organic–inorganic Pb‐based perovskites in terms of toxicity and stability, are fabricated by gas‐quenching approach in ambient environment for the first time. Moreover, the study examines the effect of gas flowing rate on the solvent evaporation rate, crystallinity, morphology, and optical properties of the perovskite. The results indicate that the duration of color change from transparent to shiny yellow during gas quenching of Cs 2 AgBiBr 6 films is influenced by the gas flowing rate, and this parameter has a notable impact on the properties of the films. In addition, incorporation of the gas‐quenched Cs 2 AgBiBr 6 thin films in perovskite solar cells leads to 1.47% power conversion efficiency with open‐circuit voltage of 1.04 V, short‐circuit current density of 2.11 mA cm −2 , and fill factor of 67.4%. Overall, this study provides a new approach to fabricate Cs 2 AgBiBr 6 thin films in ambient atmosphere for potential optoelectronic applications.