Highly efficient and stable binary and ternary organic solar cells using polymerized nonfused ring electron acceptors.

This study reports the successful design and synthesis of two novel polymerized nonfused ring electron acceptors, P-2BTh and P-2BTh-F, derived from the high-performance nonfused ring electron acceptor, 2BTh-2F. Prepared via Stille polymerization, these polymers feature thiophene and fluorinated thiophene as π-bridge units. Notably, P-2BTh-F, with difluorothiophene as the π-bridge, exhibits a more planar backbone and red-shifted absorption spectrum compared with P-2BTh. When employed in organic solar cells (OSCs) with PBDB-T as the donor material, P-2BTh-F-based devices demonstrate an outstanding power conversion efficiency (PCE) of over 11%, exceeding the 8.7% achieved by P-2BTh-based devices. Furthermore, all-polymer solar cells utilizing PBDB-T:P-2BTh-F exhibit superior storage stability. Additionally, P-2BTh-F was explored as a functional additive in a high-performance binary system, enhancing stability while maintaining comparable PCE (19.45%). This strategy offers a cost-effective approach for fabricating highly efficient and stable binary and ternary organic solar cells, opening new horizons for cost-effective and durable solar cell development.