Abstract
The relaxation dynamics of photoexcitation of poly(2,5-diethynylthiophene) copolymers (PDETs) with different repeating unit numbers (n = 12, 16, 18) were investigated by steady-state fluorescence spectroscopy and picosecond time-resolved fluorescence decay measurements. All three copolymers presented two peaks in a fluorescence spectrum; however, the position and the intensity of each peak changed, depending upon polymer size. These two peaks were assigned as radiative relaxations from a self-trapped (polaronic) exciton state and a conformational kink state, in comparison with the results of polydiacetylenes and polythiophenes. A bathochromic shift in the fluorescence spectra occurred between the PDET with n = 12 and the PDET with n = 16, but it was negligible for the PDETs with n between 16 and 18. The ratio of the populational relaxation at the conformational kink state to the relaxation at the self-trapped (polaronic) exciton state is larger in the PDET with n = 12 than in PDETs with n = 16 or n = 18. From the results of iterative least-squares fitting of time-resolved fluorescence decay data at different emission wavelengths, we obtained the relaxation lifetimes of 139 ± 5 psec and 205 ± 3 psec for each state and fluorescence build-up times of 18 ± 2 psec and 51 ± 5 psec, depending on the size of the copolymers; values which are attributed to charge carrier recombination times.
| Original language | English |
|---|---|
| Pages (from-to) | 335-339 |
| Number of pages | 5 |
| Journal | European Polymer Journal |
| Volume | 34 |
| Issue number | 3-4 |
| Publication status | Published - 1998 Mar 1 |
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All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
- Organic Chemistry
- Polymers and Plastics
- Materials Chemistry
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Excited state energy dynamics of poly(2,5-diethynylthiophene) copolymers with different effective conjugation lengths. / Hwang, In Wook; Song, Nam Woong; Park, Young Tae; Kim, Dongho; Kim, Yong Rok.
In: European Polymer Journal, Vol. 34, No. 3-4, 01.03.1998, p. 335-339.Research output: Contribution to journal › Article
TY - JOUR
T1 - Excited state energy dynamics of poly(2,5-diethynylthiophene) copolymers with different effective conjugation lengths
AU - Hwang, In Wook
AU - Song, Nam Woong
AU - Park, Young Tae
AU - Kim, Dongho
AU - Kim, Yong Rok
PY - 1998/3/1
Y1 - 1998/3/1
N2 - The relaxation dynamics of photoexcitation of poly(2,5-diethynylthiophene) copolymers (PDETs) with different repeating unit numbers (n = 12, 16, 18) were investigated by steady-state fluorescence spectroscopy and picosecond time-resolved fluorescence decay measurements. All three copolymers presented two peaks in a fluorescence spectrum; however, the position and the intensity of each peak changed, depending upon polymer size. These two peaks were assigned as radiative relaxations from a self-trapped (polaronic) exciton state and a conformational kink state, in comparison with the results of polydiacetylenes and polythiophenes. A bathochromic shift in the fluorescence spectra occurred between the PDET with n = 12 and the PDET with n = 16, but it was negligible for the PDETs with n between 16 and 18. The ratio of the populational relaxation at the conformational kink state to the relaxation at the self-trapped (polaronic) exciton state is larger in the PDET with n = 12 than in PDETs with n = 16 or n = 18. From the results of iterative least-squares fitting of time-resolved fluorescence decay data at different emission wavelengths, we obtained the relaxation lifetimes of 139 ± 5 psec and 205 ± 3 psec for each state and fluorescence build-up times of 18 ± 2 psec and 51 ± 5 psec, depending on the size of the copolymers; values which are attributed to charge carrier recombination times.
AB - The relaxation dynamics of photoexcitation of poly(2,5-diethynylthiophene) copolymers (PDETs) with different repeating unit numbers (n = 12, 16, 18) were investigated by steady-state fluorescence spectroscopy and picosecond time-resolved fluorescence decay measurements. All three copolymers presented two peaks in a fluorescence spectrum; however, the position and the intensity of each peak changed, depending upon polymer size. These two peaks were assigned as radiative relaxations from a self-trapped (polaronic) exciton state and a conformational kink state, in comparison with the results of polydiacetylenes and polythiophenes. A bathochromic shift in the fluorescence spectra occurred between the PDET with n = 12 and the PDET with n = 16, but it was negligible for the PDETs with n between 16 and 18. The ratio of the populational relaxation at the conformational kink state to the relaxation at the self-trapped (polaronic) exciton state is larger in the PDET with n = 12 than in PDETs with n = 16 or n = 18. From the results of iterative least-squares fitting of time-resolved fluorescence decay data at different emission wavelengths, we obtained the relaxation lifetimes of 139 ± 5 psec and 205 ± 3 psec for each state and fluorescence build-up times of 18 ± 2 psec and 51 ± 5 psec, depending on the size of the copolymers; values which are attributed to charge carrier recombination times.
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M3 - Article
AN - SCOPUS:0009491751
VL - 34
SP - 335
EP - 339
JO - European Polymer Journal
JF - European Polymer Journal
SN - 0014-3057
IS - 3-4
ER -