Femtosecond Differential Transmission Spectroscopy of α-Sexithienyl Single Crystals at Low Temperature
Spectral relaxation of photogenerated excitations and stimulated emission is investigated in an α-sexithienyl single crystal. We have performed femtosecond differential transmission spectroscopy, probing the spectral region from 1.85 to 2.6 eV, and time-resolved photoluminescence measurements at low...
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| Published in: | The journal of physical chemistry. B Vol. 104; no. 51; pp. 12210 - 12214 |
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| Main Authors: | , , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
American Chemical Society
28-12-2000
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| Online Access: | Get full text |
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| Summary: | Spectral relaxation of photogenerated excitations and stimulated emission is investigated in an α-sexithienyl single crystal. We have performed femtosecond differential transmission spectroscopy, probing the spectral region from 1.85 to 2.6 eV, and time-resolved photoluminescence measurements at low temperature. Stimulated emission with amplification of the probe light which results in a positive differential transmission signal is observed at two spectral positions for polarization parallel to the molecular c-axis. The observed stimulated emission decays with a time constant of 85 ps. Different kinetics of the rise of the stimulated emission and the superimposed excited-state absorption has been observed for excitation with 3.1 eV. This difference vanishes for excitation with 2.3 eV. Stimulated emission proceeds also via trap luminescence. |
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| Bibliography: | ark:/67375/TPS-1SK09PC2-T istex:0EFB0FDA70AE8DC64B1EF8F1E261CA6A336DE819 |
| ISSN: | 1520-6106 1520-5207 |
| DOI: | 10.1021/jp002838e |