Relaxation dynamics of photoexcitations in polydiacetylene films

Author

Yoshizawa, Masayuki ; Taiji, M. ; Kobayashi, Takayoshi

Author_Institution

Dept. of Phys., Tokyo Univ., Japan

Volume

25

Issue

12

fYear

1989

fDate

12/1/1989 12:00:00 AM

Firstpage

2532

Lastpage

2539

Abstract

The relaxation dynamics of photoexcitations in a polydiacetylene (poly-3BCMU) film was investigated by femtosecond time-resolved absorption spectroscopy. Spectral change due to several nonlinear optical processes, i.e. hole burning, Raman gain, and dynamic Stark effect, was observed. The difference absorption spectra of singlet and triplet excitons minus ground state were measured. The photoexcited singlet excitons relaxed to the self-trapped state with the time constant of 150±50 fs. The lifetime of the self-trapped excitons was 2.0±0.1 ps at 10 K and 1.5±0.2 ps at 290 K. The lifetime of the triplet excitons was much longer than several tens of picoseconds and was consistent with the lifetime of 18 μs obtained by nanosecond spectroscopy

Keywords

Stark effect; excitons; high-speed optical techniques; optical hole burning; polymer films; time resolved spectra; visible spectra of organic molecules and substances; 1.5 ps; 10 K; 150 fs; 18 mus; 2 ps; 290 K; Raman gain; difference absorption spectra; dynamic Stark effect; exciton lifetime; exciton relaxation; femtosecond time-resolved absorption spectroscopy; ground state; hole burning; nanosecond spectroscopy; nonlinear optical processes; photoexcitations; photoexcited singlet excitons; poly-3BCMU film; polydiacetylene films; relaxation dynamics; self-trapped excitons; self-trapped state; singlet excitons; spectral changes; time constant; triplet excitons; Absorption; Excitons; Kinetic theory; Optical films; Optical polymers; Optical solitons; Polymer films; Spectroscopy; Stationary state; Ultrafast optics;

fLanguage

English

Journal_Title

Quantum Electronics, IEEE Journal of

Publisher

ieee

ISSN

0018-9197

Type

jour

DOI

10.1109/3.40639

Filename

40639