2D/1A ternary blend system enables non-fused ring electron acceptor based polymer solar cells with improved photovoltaic parameters

Abstract

Non-fused ring electron acceptors (NFRAs), whose central skeletons are selected from simple aromatic rings, have been developed to be the promising candidates to maintain a rational balance between cost and performance. In this work, a 2D/1A ternary blend system, with polymers PM6 and PTQ10 as the two donor components and small molecular BDDEH-4F as the NFRA, was designed for polymer solar cells (PSCs). Comparing with power conversion efficiencies (PCEs) of 12.16% and 8.28% for the PM6 and PTQ10 based binary active layers, respectively, the optimized PM6:PTQ10:BDDEH-4F = 0.85:0.15:1 ternary active layer could show improved photovoltaic parameters, giving a higher PCE of 13.04%. Based on Flory-Huggins interaction parameter estimations, PTQ10 is more miscible to the NFRA if compared with PM6, and thus the addition of PTQ10 in the ternary active layer would tune the morphology. Enhanced exciton dissociation, suppressed trap-assisted recombination, higher and more balanced charge mobilities, and optimized morphology were achieved for the ternary blend system, finally contributing to the improved photocurrent and fill factor. Polymer PTQ10 is a notable low cost donor. Therefore, the 2D/1A ternary strategy should provide a ternary active layer with cost saving advantage. • 2D/1A ternary active layer for non-fused ring electron acceptor. • The ternary solar cells showing PCE of 13.04%, higher than 8.28–12.16% for binary solar cells. • The ternary active layer provides cost saving advantage.