Open AccessEffect of the electric field on the decay of excited states in poly-phenylenevinylene
Author(s) -
Cheng Peng,
Feng Gao,
Xiangdong Chen,
Jian Yang
Publication year - 2010
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.59.2831
Subject(s) - electric field , exciton , excitation , relaxation (psychology) , amplitude , excited state , atomic physics , time constant , physics , field (mathematics) , phonon , luminescence , materials science , condensed matter physics , molecular physics , optoelectronics , optics , mathematics , quantum mechanics , pure mathematics , psychology , social psychology , electrical engineering , engineering
To gain an insight into the effect of electric field on the electro-luminescence of organic light emission diode, the ultrafast pump-probe spectroscopy is used to investigate the transient phenomena of the excitons induced by the electric field. Under the excitation density of 230 μJ/cm2, the decay of the singlet excitons shows a fast and a slow component. The amplitude factor and the relaxation time of fast component are field-dependent. Compared with the zero biascase, the relaxation time of the fast component becomes faster at a bias of 6.4×105 V/cm, its amplitude factor is increased from 22% to 72%, about 50% initial excitons are dissociated by the electric field. The slow component is field-independent, its relaxation time-constant is about 890 ps. The longitudinal acoustic phonons with sound velocity of 17 /ps generated by excitation pulse are observed.