Achieving unprecedented power-output in 4-terminal mirror-symmetrical printable carbon CsPbBr3 solar cells through dual-solvent engineering†

Abstract

Conventional aqueous processing of all-inorganic CsPbBr₃ perovskite solar cells has encountered significant limitations hindering performance optimization and long-term stability. To address these challenges, we introduce a novel dual-solvent engineering strategy guided by density functional theory (DFT) calculations and Tyndall effect analysis. By carefully selecting solvents with enhanced donor numbers and dielectric constants, the surface Br/Pb ratio of CsPbBr₃ was effectively modulated, inducing p-type transition, and suppressing defect formation within the perovskite film. These synergistic effects lead to extended carrier lifetimes, reduced defect densities, and improved charge transport properties. Consequently, our all-inorganic carbon-based printable mesoscopic perovskite solar cells (p-MPSCs) achieve a record power conversion efficiency (PCE) of 10.18% (with a large-area device of 17.88 cm² reaching 8.72%). Furthermore, integrating a 4-terminal mirror reflection concentrator significantly boosts power output to 29.44 mW cm⁻². Remarkably, the devices exhibit exceptional stability, retaining 93.2% of their initial PCE after 1000 hours of operation at 150 °C. Our findings establish a promising pathway towards high-performance and stable all-inorganic perovskite solar cells suitable for large-scale applications.