Definitive assignment and mechanistic study of interfacial charge-transfer transitions between ZnO and benzenethiol

Highlights: • Interfacial charge-transfer transitions between ZnO and aromatic thiols. • Definitive assignment of interfacial charge-transfer transitions. • Elucidation of the mechanism of interfacial charge-transfer transitions. Interfacial charge-transfer transitions (ICTTs) between organic compounds and inorganic semiconductors have recently attracted increasing interest for their potential applications in solar energy conversions and biosensing due to the key features of visible-light absorption with colourless organic molecules and direct photoinduced charge separation. Recently, we first reported ICTT between ZnO nanoparticles and aromatic thiols such as benzene thiol (BT). Here, we computationally examine ICTT between ZnO and BT with density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. Our research provides the definitive assignment of ICTT in the ZnO-BT surface coordination complex and clarifies the mechanism of the ICTT.