Release Time:2019-03-09  Hits:

Indexed by: Journal Article

Date of Publication: 2010-12-01

Journal: CHINESE JOURNAL OF CHEMICAL PHYSICS

Included Journals: Scopus、CSCD、SCIE

Volume: 23

Issue: 6

Page Number: 637-642

ISSN: 1674-0068

Key Words: Volume-conserved twisted state; Time-resolved photon emission; Photoisomerization

Abstract: The excited state characters of HY103 have been studied by means of time-resolved photon emission (time-correlated single photon counting) and time dependent density functional theory calculations. The experimental and theoretical results demonstrate that HY103 dyes undergo an efficient one-bond-flip motion after photoexicitation at room temperature, which leads to a very short lifetime of the normal fluorescence state, and a weak fluorescence emission around 670 rim. However, when HY103 are excited in amorphous glasses at 77 K, the normal fluorescence emission is prolonged to nanoseconds time scale about 2 us, and the fluorescence emission is enhanced. Furthermore, a new emission state is produced, which is characterized as a volume-conserved twisted (VCT) state. This is the first observation of a VCT state. The experiment indicates that the VCT motion of excited state of pi-conjugated molecules in restricted environment can form a stable emission state, and the excited state character of pi-conjugated molecules in restricted environment is complex.