Bange, Sebastian and Scherf, Ullrich and Lupton, John M. (2012) Absence of Singlet Fission and Carrier Multiplication in a Model Conjugated Polymer: Tracking the Triplet Population through Phosphorescence. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 134 (4). pp. 1946-1949. ISSN 0002-7863,
Full text not available from this repository. (Request a copy)Abstract
Singlet fission, or multiple exciton generation, has been purported to occur in a variety of material systems. Given the current interest in exploiting this process in photovoltaics, we search for the direct signature of singlet fission, phosphorescence from the triplet state, in a model polymeric organic semiconductor for which photoinduced absorption experiments have implied a tripling of the intersystem crossing yield at the onset of fission. Fluorescence and phosphorescence are clearly discriminated using a picosecond gated photoluminescence excitation technique, at variable temperature. At low excitation densities, in a quasi-steady-state experiment, we detect no change of the relative triplet yield to within 4% for photon energies of almost three times the triplet energy of 2.1 eV. Identical results are obtained under nonlinear two-photon excitation. We conclude that assignments of singlet fission based on induced absorptions alone should be treated with caution and may substantially overestimate excited-state intersystem crossing yields, raising questions with regards to the applicability of the process in devices.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | LADDER-TYPE POLY(PARA-PHENYLENE); MULTIPLE EXCITON GENERATION; CHARGED EXCITATIONS; MAGNETIC-FIELD; QUANTUM DOTS; SOLAR-CELLS; SPECTROSCOPY; FUSION; FILMS; PHOTOGENERATION; |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Experimental and Applied Physics > Chair Professor Lupton > Group John Lupton |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 19 May 2020 11:02 |
| Last Modified: | 19 May 2020 11:02 |
| URI: | https://pred.uni-regensburg.de/id/eprint/19277 |
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