Novel thiophene[3,4-b]thiophene-based polymer acceptors for high-performance all-polymer solar cells

This work developed three thiophene[3,4-b]thiophene-based polymer acceptors using a polymerized small-molecule acceptor strategy. The thiophene π-bridge integration and optimized side-chains enhanced the device performance. The PM6:PYF-EF binary devices achieved 17.07% PCE, which further reached 18.62% in the PM6:PY-IT:PYF-EF ternary blends.