Enhancing performance of tin-based perovskite solar cells via fused-ring electron acceptor

The performance of tin-based perovskite solar cells has been substantially hampered by voltage loss caused by energy level mismatch, charge recombination, energetic disorder, and other issues. Here, a fused-ring electron acceptor based on indacenodithiophene (IDIC) was for the first time introduced as a transition layer between a tin-based perovskite layer and a C₆₀ electron transport layer, leading to better matched energy levels in the device. In addition, coordination interactions between IDIC and perovskite improved the latter's crystallinity. The introduction of IDIC raised the power conversion efficiency from 8.98% to 11.5% and improved the device's stability. The decomposition mechanism of tin-based perovskite was also revealed by detecting the optical properties of perovskite microdomains through innovative integration of confocal laser scanning microscopy and photoluminescence spectroscopy.