An oxygen heterocycle-fused fluorene based non-fullerene acceptor for high efficiency organic solar cells

Abstract

A new acceptor–donor–acceptor (A–D–A) small molecule acceptor, named FCO-2F, is designed and synthesized based on the previous acceptor F-H. By inserting an oxygen atom into the backbone of F-H and fluorination on the end group, FCO-2F shows a much red-shifted absorption compared with F-H, and also a wider absorption up to 830 nm. Using polymer PM6 as the donor, the organic solar cell (OSC) devices based on FCO-2F offer a power conversion efficiency (PCE) of 13.36%, with a much improved short circuit current (J_sc) of 20.90 mA cm⁻².