Abstract

The trade-off between efficiency and stability is a bit vague, and it is often tricky to precise control of the bulk morphology for simultaneously improving device efficiency and stability.

Herein, three fused-ring conducted polymer acceptors containing furan, thiophene, and selenophene as the electron linkers in their conjugated backbones, namely PY-O, PY-S, and PY-Se, were designed and synthesized. The electron linker engineering affects the intermolecular interactions of relative polymer acceptors and their charge transport properties.

Furthermore, excellent material compatibility was achieved when PY-Se was blended with polymer donor PBDB-T, resulting in nanoscale domains with favorable phase separation. The optimized PBDB-T: PY-Se blend not only exhibits maximum performance with a power conversion efficiency of 15.48%, which is much higher than those of PBDB-T: PY-O (9.80%) and PBDB-T: PY-Se (14.16%) devices, but also shows better storage and operational stabilities, and mechanical robustness.

This work demonstrates that the precise modification of electron linkers can be a practical way to simultaneously actualize molecular crystallinity and phase miscibility for improving the performance of all-polymer solar cells, showing practical significance.