Monolithic Two-Terminal Perovskite/CIS Tandem Solar Cells with Efficiency Approaching 25.

Monolithic two-terminal (2T) perovskite/CuInSe (CIS) tandem solar cells (TSCs) combine the promise of an efficient tandem photovoltaic (PV) technology with the simplicity of an all-thin-film device architecture that is compatible with flexible and lightweight PV. In this work, we present the first-ever 2T perovskite/CIS TSC with a power conversion efficiency (PCE) approaching 25% (23.5% certified, area 0.