Poly(3-hexylthiophene)-based non-fullerene solar cells achieve high photovoltaic performance with small energy loss

Abstract

Regioregular poly(3-hexylthiophene) (P3HT) as one of the most commonly used and thoroughly studied homopolymers has been demonstrated to be a promising commercial candidate for large-area, roll-to-roll printed solar cells. In this work, we designed a new low-bandgap electron acceptor material ATT-3 by combining rhodanine and octyl thieno[3,4-b]thiophene-2-carboxylate as the electron-deficient part. ATT-3 shows a planar backbone configuration facilitating charge transport and exhibits strong and broad absorption ranging from 300 to 770 nm with an optical bandgap of 1.61 eV. ATT-3 shows a complementary absorption and well-matched HOMO and LUMO energy levels with P3HT. P3HT:ATT-3-based PSCs show a high PCE of 6.26% with a high V_oc of 0.927 V and a small energy loss of 0.68 eV, which is comparable to the best value obtained by using an O-IDTBR acceptor.