Non‐Toxic and Stable Double Perovskite Solar Cells Based on Cs2AgSbX6 Light Harvester: First Principle Calculations‐Aided Theoretical Estimation

Abstract Owing to the low long‐term stability and high toxicity, high‐efficiency perovskite solar cells are yet to be commercialized. Therefore, it is imperative to find a reliable and environmentally benign alternative perovskite light harvester. Herein, the study presents a non‐toxic double perovskite light harvester based on Cs 2 AgSbX 6 (where X = Cl, Br, and I) as a substitute, which can render both high efficiency and long‐term durability. The optoelectronic properties of the Cs 2 AgSbX 6 double perovskite light harvesters are investigated with the Cambridge Serial Total Energy Package (CASTEP) software package that is committed to density functional theory (DFT). The bandgap (indirect) tunability of Cs 2 AgSbX 6 double perovskite light harvesters and associated changes in the density of states (DOS) are explored. The obtained results are further loaded as input to the SCAPS‐1D software package to assess the potential of Cs 2 AgSbX 6 double perovskite solar cells. With the FTO/AZnO/Cs 2 AgSbX 6 /MoO 3 /rear contact device structure, the thickness and bulk defect density of the Cs 2 AgSbX 6 light harvester have superior control over the performance of the double perovskite solar cells. The highest theoretical efficiency of ≈29.9% is estimated for the Cs 2 AgSbI 6 light harvester. Additionally, the effectiveness of several prospective back electrodes is examined.