Recent Progress in Cesium‐Based Lead‐Free Halide Double Perovskite Materials for Photovoltaic Applications

Perovskite materials have revolutionized photovoltaic technology and become the vanguard of current research owing to their facile solution processability and exceptional enhancement in power conversion efficiency (PCE), reaching 25.2% to date. Unfortunately, lead toxicity is the major hurdle for perovskite solar cells (PSCs) for their scalability and prevalent commercialization. To tackle the toxicity issue, lead‐free perovskite and double perovskite materials are potential contenders in the photovoltaic world. Herein, a comprehensive study of lead‐free halide double perovskite materials with the formula A 2 BB’X 6 is provided. Notably, the structure and design of the lead‐free light‐harvesting layer of Cs 2 BB’X 6 is emphasized. Moreover, different organic–inorganic lead‐free halide double perovskite layers‐based solar devices are explored with their designed configurations and physical parameters. Finally, recent significant advancement in lead‐free double PSCs are reviewed, and the future outlook associated with lead‐free double perovskite devices is also deliberated to attain a promising pathway toward highly efficient and stable perovskite solar devices.