Interfacial electron transfer plays a critical role in solar energy conversion, environmental redox remediation, and photocatalysis. Extensive ensemble-averaged studies have indicated inhomogeneous and complex dynamics of interfacial ET reaction. To characterize the inhomogeniety and the complex mechanism, we have applied single-molecule spectroscopy and correlated AFM/STM imaging to study the Interfacial ET dynamics of dye molecules adsorbed at the surface of TiO2 nanoparticles. The interfacial ET activity of individual dye molecules showed fluctuations and intermittency at a wide time scale. The fluctuation dynamics were found to be inhomogeneous from molecule to molecule and from time to time, showing significant static and dynamic disorders in the dynamics. Furthermore, we have applied site-specific AFM-Raman spectroscopy on analyzing ET associated mode-specific vibrational reorganization energy barriers. Our experiments revealed site-to-site variations in the vibrational reorganization energy barriers in the interfacial ET systems. Our recent experiments on single-molecule spontaneous ground-state electron transfer fluctuation will also be discussed.

Probing single-molecule interfacial electron transfer dynamics in solar energy systems

251st National Meeting (2016)

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