Electron-Rich Anthracene Semiconductors Containing Triarylamine for Solution-Processed Small-Molecule Organic Solar Cells

Abstract

New electron-rich anthracene derivatives containing triarylamine hole stabilizers, 2,6-bis[5,5'-bis(N,N'-diphenylaniline)-2,2'-bithiophen-5-yl]-9,10-bis-[(triisopropylsilyl)ethynyl]anthracene (TIPSAntBTTPA) and 2,6-bis(5,5'-bis{4-[bis(9,9-dimethyl-9H-fluoren-2-yl)amino]phenyl}-2,2'-bithiophen-5-yl)-9,10-bis-[(triisopropylsilyl)ethynyl]anthracene (TIPSAntBTbisDMFA), linked with p-conjugated bithiophene bridges, were synthesized and their photovoltaic characteristics were investigated in solution-processed small-molecule organic solar cells (SMOSCs). These new materials exhibited superior intramolecular charge transfer from triarylamine to anthracene, leading to a more electron-rich anthracene core that facilitated electron transfer into phenyl-C61-butyric acid methyl ester. Compared with TIPSAntBT and triarylamine, these materials show a threefold improvement in hole-transporting properties and better photovoltaic performance in solution-processed SMOSCs, with the best power conversion efficiency being 2.96?% at a high open-circuit voltage of 0.85 V.