Miscibility Matching and Bimolecular Crystallization Affording High-performance Ternary Nonfullerene Solar Cells

How the interaction between a third component and a donor/acceptor affects the crystallization and phase separation of the active layer remains to be explored from the perspective of miscibility. To demonstrate the miscibility matching in nonfullerene-based ternary organic solar cells, the poly[(4,4′-bis(2-butyloctoxycarbonyl-[2,2′-bithiophene]-5,5-diyl)-alt-(2,2′-bithiophene-5,5′-diyl)] (PDCBT) and poly(3-hexylthiophene) (P3HT), showing similar chemical structures despite their dissimilar side chains, were selected as third components to incorporate into the poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)-benzo[1,2-b:4,5-b′]dithiophene))-alt-(5,5-(1′,3′-di-2-thienyl-5′,7′-bis(2-ethylhexyl)benzo[1′,2′-c:4′,5′-c′]dithiophene-4,8-dione))]: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 (PBDB-T:ITIC) system. On the basis of the melting point depression method, the Flory–Huggins interaction parameters for ...