Efficient and Stable Inverted Wide‐Bandgap Perovskite Solar Cells and Modules Enabled by Hybrid Evaporation‐Solution Method

Abstract

AbstractWide‐bandgap perovskite solar cells (WBG‐PSCs), when partnered with Si bottom cells in tandem configuration, can provide efficiencies up to 44%; yet, the development of stable, efficient, and scalable WBG‐PSCs is required. Here, the utility of the hybrid evaporation‐solution method (HESM) is investigated to meet these demanding requirements via its unique advantages including ease of control and reproducibility. A PbI2/CsBr layer is co‐evaporated followed by coating of organic‐halide solutions in a green solvent. Bandgaps between 1.55–1.67 eV are systematically screened by varying CsBr and MABr content. Champion efficiencies of 21.06% and 20.35% in cells and 19.83% and 18.73% in mini‐modules (16 cm2) for perovskites with 1.64 and 1.67 eV bandgaps are achieved, respectively. Additionally, 18.51%‐efficient semi‐transparent WBG‐PSCs are implemented in 4T perovskite/bifacial silicon configuration, reaching a projected power output of 30.61 mW cm−2 based on PD IEC TS 60904‐1‐2 (BiFi200) protocol. Despite similar bandgaps achieved by incorporating Br via MABr solution and/or CsBr evaporation, PSCs having a perovskite layer without MABr addition show significantly higher thermal and moisture stability. This study proves scalable, high‐performance, and stable WBG‐PSCs are enabled by HESM, hence their use in tandems and in emerging applications such as indoor photovoltaics are now within reach.