Femtosecond transient absorption spectroscopy of nanocrystalline polydiacetylene colloids

被引:9
作者
Asahi, Tsuyoshi [1 ]
Kibisako, Kazumasa [1 ]
Masuhara, Hiroshi [1 ]
Kasai, Hitoshi [2 ]
Katagi, Hideyuki [2 ]
Oikawa, Hidetoshi [2 ]
Nakanishi, Hachiro [2 ]
机构
[1] Osaka Univ, Dept Appl Phys, Suita, Osaka 565, Japan
[2] Tohoku Univ, Inst Chem React Sci, Aoba Ku, Sendai, Miyagi 980, Japan
来源
MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY SECTION A-MOLECULAR CRYSTALS AND LIQUID CRYSTALS | 1998年 / 314卷
关键词
microcrystals; polydiacetylene; femtosecond absorption spectroscopy; cooling dynamics; size dependence;
D O I
10.1080/10587259808042462
中图分类号
O7 [晶体学];
学科分类号
0702 ; 070205 ; 0703 ; 080501 ;
摘要
Femtosecond transient absorption spectral measurements have been performed for size-controlled polydiacetylene microcrystals (30, 100, and 150 nm mean diameter) dispersed in water. Ultrafast relaxation processes within 5 ps after excitation were attributed to formation and decay of self-trapped exciton, which was independent on the size. A time-dependent spectral shift of transient bleaching, corresponding to the stationary excitonic absorption band, was observed in the time region from 10 ps to a few ns. It is explained as a thermalization of absorbed light energy within the microcrystal and the succeeding cooling by comparing transient absorption spectra with temperature difference spectra of the ground state absorption. Size-dependent cooling dynamics of a 'hot' microcrystal was successfully demonstrated; the time constant increases with the crystal size.
引用
收藏
页码:95 / 100
页数:6
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