Design of Bridge Molecules for High-Efficiency FAPbI3-Based Perovskite Solar Cells

Manipulation of interfacial defects and carrier extraction or transport are crucial for improving the operational stability and photovoltaic performance of perovskite solar cells (PSCs). Here, we propose a technique utilizing bridge molecules to construct a carrier viaduct between perovskite bulk and hole-transporting layers. A molecular bridge configuration combining organic functional groups from each layer was used. The designed bridge molecules not only ensure homogeneous contact and promote carrier extraction/transport but also passivate various defects and redistribute the surface potential. The developed device showed an exceptional power conversion efficiency (PCE) of 25.49% with enhanced operational stability. The treated PSCs could retain over 94% of their initial PCEs after 1000 h of continuous operation under 1 sun illumination and over 95% of their initial PCEs after 500 h of aging at approximately 85 °C in dry air with a relative humidity of 20%. This work provides a simple yet effective approach for fabricating perovskite photovoltaics with outstanding performance and operational stability.