Inverted Ternary Organic Photovoltaics with Alloyed Acceptor Exhibiting 12.29% Efficiency

Abstract

A series of inverted organic photovoltaics (OPVs) are fabricated with PBDB‐T as donor and nonfullerene materials (ITCC and IT‐M) as acceptors, respectively. Power conversion efficiencies (PCEs) of IT‐M‐ and ITCC‐based OPVs are 11.20% and 8.70%, respectively. A 12.29% PCE is achieved from the optimized ternary OPVs with active layers containing 20 wt% ITCC in acceptors, resulting from the simultaneous improvement of the fill factor (FF) of 74.31%, short‐circuit current density (JSC) of 17.41 mA cm−2, as well as open‐circuit voltage (VOC) of 0.952 V. Over 9% PCE improvement is obtained by using the ternary strategy, which is attributed to the complementary absorption spectra, excellent compatibility, as well as well‐matched energy levels of used materials. This work indicates the ternary strategy as an efficient method to achieve efficient OPVs while keeping the simplicity of the fabrication process.