New small-molecule acceptors based on hexacyclic naphthalene(cyclopentadithiophene) for efficient non-fullerene organic solar cells

Abstract

A series of new non-fullerene small molecule acceptors (NTIC, NTIC-Me, NTIC-OMe and NTIC-F) based on the acceptor–donor–acceptor (A–D–A) architecture, using hexacyclic naphthalene-(cyclopentadithiophene) as the central unit, were designed and synthesized. The non-fullerene OSC device based on PBDB-T:NTIC showed a highest PCE of 8.63%. With a relatively high-lying LUMO level of NTIC-OMe, the PBDB-T:NTIC-OMe based device obtained a comparatively high V_oc of 0.965 V and a PCE of 8.61% simultaneously. The results demonstrate that the naphthalene core is a promising building block for constructing highly efficient non-fullerene acceptors and further boosting the photovoltaic performance of the devices.