Using confocal microscopy to study the dynamic process of single oxazine 1 molecules adsorbed on TiO2 nanoparticles
Date Issued
2006
Date
2006
Author(s)
Chen, Yi-Ju
DOI
en-US
Abstract
For single molecule spectroscopy (SMS), the molecules are typically studied one at a time by focusing the laser to a diffraction-limited spot and centering the molecule of interest at the laser focal volume. The fluorescence from the molecule is collected, the intensity, and spectrum can be studied for each particular molecule. Notch and band-pass filters are commonly used to prevent the excitation light from reaching the detector. The main advantage of SMS is the ability to explore of heterogeneity in complex materials (like polymer films and glasses) as well as direct observation of dynamical state changes arising from photophysics and photochemistry.
Here we describe a detailed investigation of the fluorescence intensity dynamics before photobleaching. We report on single-molecule studies of photosensitized interfacial electron transfer process in Oxazine 1 - TiO2 nanoparticles (NPs) system. We characterized the triplet-state blinking dynamics and electron transfer dynamics by analyzing the autocorrelation functions. The blinking time due to the triplet state is clearly distinguished from the fluorescence intensity fluctuation time of subseconds to seconds due to electron transfer (ET) process. We observed that the interfacial ET of single molecules on the surface of TiO2 NPs are statically inhomogeneous, varying the rate of the ET reactivity fluctuations from molecule to molecule. Furthermore, dynamic inhomogeneity is associated with the ET fluctuations from time to time for the same individual molecule. These inhomogeneities may be attributed to the difference of Franck-Condon coupling and molecule-surface vibronic coupling caused by different environment.
Subjects
單分子
螢光
電子傳遞
太陽能染料電池
single molcule
fluorescence
confocal microscopy
dye sensitized solar cell
Type
thesis
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