Size-dependent fluorescence emission spectra and lifetimes of microcrystals of the dye N,N'-bis(2,5-di-tert-butylphenyl)-3,4:9,10-perylenebis(dicarboximide) (DBPI) studied by confocal fluorescence microscopy
[2] INDIAN INST TECHNOL,DEPT PHYS,MADRAS 600036,TAMIL NADU,INDIA
来源:
JOURNAL OF PHYSICAL CHEMISTRY B
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1997年
/
101卷
/
41期
关键词:
D O I:
10.1021/jp9710087
中图分类号:
O64 [物理化学(理论化学)、化学物理学];
学科分类号:
070304 ;
081704 ;
摘要:
The time-correlated single-photon counting (TCSPC) technique combined with confocal fluorescence microscopy has revealed the nonexponential character of the fluorescence decay (0.1-10 ns) for highly fluorescent single microcrystals of the dye N,N'-bis(2,5-di-tert-butylphenyl)-3,4:9 (DBPI) of a size as small as a few micrometers. Steady-state and time-resolved emission spectra of the microcrystals have also been measured with a fluorescence microscope. A size dependence is observed for both fluorescence emission spectra and lifetimes. The fluorescence decay profiles of the microcrystals, when observed with confocal optics, exhibit a dominant contribution of a short-lived (0.11-0.14 ns) component. From these results it has been concluded that the self-absorption effect is playing a major role in characterizing the fluorescence of microcrystals of DBPI with no contribution from any new emitting species.