Benzimidazole-Branched Isomeric Dyes: Effect of Molecular Constitution on Photophysical, Electrochemical, and Photovoltaic Properties.

摘要: Three benzimidazole-based isomeric organic dyes possessing two triphenylamine donors and a cyanoacrylic acid acceptor are prepared by stoichiometrically controlled Stille or Suzuki–Miyaura coupling reaction which predominantly occurs on the N-butyl side of benzimidazole due to electronic preferences. Combined with steric effect substituent, placement segment at various nuclear positions such as C2, C4, C7 led remarkable variations in intramolecular charge transfer absorption, electron injection efficiency, recombination kinetics. The substitution C4 red-shifted while that retarded twisting structure caused butyl group. Because cross-conjugation nature poor interaction between donor acceptor, dye containing units unit C2 showed low oxidation potential. Thus, this po...