Efficient Approach for Improving the Performance of Nonhalogenated Green Solvent-Processed Polymer Solar Cells via Ternary-Blend Strategy

The ternary-blend approach has the potential to enhance the power conversion efficiencies (PCEs) of polymer solar cells (PSCs) by providing complementary absorption and efficient charge generation. Unfortunately, most PSCs are processed with toxic halogenated solvents, which are harmful to human health and the environment. Herein, we report the addition of a nonfullerene electron acceptor 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′]dithiophene (ITIC) to a binary blend (poly[4,8-bis(2-(4-(2-ethylhexyloxy)3-fluorophenyl)-5-thienyl)benzo[1,2-b:4,5-b′]dithiophene-alt-1,3-bis(4-octylthien-2-yl)-5-(2-ethylhexyl)thieno[3,4-c]pyrrole-4,6-dione] (P1):[6,6]-phenyl-C71-butyric acid methyl ester (PC71BM), PCE = 8.07%) to produce an efficient nonhalogenated green solvent-processed ternary PSC system with a high PCE of 10.11%. The estimated wetting coefficient value (0.086) for the ternary blend suggests that ITIC could be l...