High mobility acceptor as third component enabling high-performance large area and thick active layer ternary solar cells

Organic solar cells (OSCs) adopting nonfullerene acceptors have realized over 18% power conversion efficiency (PCE). It is however challenging to achieve highly efficient devices with active layers over 200 nm thickness. Herein, we report high-performance large-area and thick-film ternary OSCs by incorporating high electron mobility IDIC into PM6:IM-4F host blend. The addition of IDIC significantly improves the crystallinity and intensifies face-on orientation in proper multi-length morphology for enhanced charge transport in active layers. As a result, the optimized ~100 nm-thick ternary OSCs with 10 wt% IDIC in the acceptors exhibit a high PCE of 15.86% for small-area (0.04 cm2) and 14.80% for large-area (0.50 cm2) devices. Importantly, the optimal ternary OSCs present excellent tolerance to the active layer thickness (≈65–353 nm). The 282 nm-thick devices contribute a PCE of 14.43% and a FF of 71.23%, among the highest values for OSCs with similar active layer thicknesses reported to date, even outperforming the remarkable 300 nm-thick PM6:Y6 system. Our work demonstrates that ternary OSCs by introducing high mobility acceptor as third component to host binary blends featuring high current and low energy loss have great potential for large-scale fabrication of highly-efficient thick-film OSCs for practical application.