Probing single-molecule interfacial electron transfer dynamics of porphyrin on TiO2 nanoparticles

Yuanmin Wang; Xuefei Wang; Sujit Kumar Ghosh; H Peter Lu

doi:10.1021/ja806988d

Probing single-molecule interfacial electron transfer dynamics of porphyrin on TiO2 nanoparticles

J Am Chem Soc. 2009 Feb 4;131(4):1479-87. doi: 10.1021/ja806988d.

Authors

Yuanmin Wang¹, Xuefei Wang, Sujit Kumar Ghosh, H Peter Lu

Affiliation

¹ Bowling Green State University, Center for Photochemical Sciences, Department of Chemistry, Bowling Green, Ohio 43403, USA.

PMID: 19138077
DOI: 10.1021/ja806988d

Abstract

Single-molecule interfacial electron transfer (ET) dynamics has been studied by using single-molecule fluorescence spectroscopy and microscopic imaging. For a single-molecule zinc-tetra (4-carboxyphenyl) porphyrin (ZnTCPP)/TiO(2) nanoparticle system, the single-molecule fluorescence trajectories show strong fluctuation and blinking between bright and dark states. The intermittency and fluctuation of the single-molecule fluorescence are attributed to the variation of the reactivity of interfacial electron transfer. The nonexponential autocorrelation function and the power-law distribution of the probability density of dark times imply the dynamic and static inhomogeneities of the interfacial ET dynamics. On the basis of the power-law analysis, the variation of single-molecule interfacial ET reactivity is analyzed as a fluctuation according to the Levy statistics.