Linfoot, Charlotte L. and Leitl, Markus J. and Richardson, Patricia and Rausch, Andreas F. and Chepelin, Oleg and White, Fraser J. and Yersin, Hartmut and Robertson, Neil (2014) Thermally Activated Delayed Fluorescence (TADF) and Enhancing Photoluminescence Quantum Yields of [Cu-I(diimine)(diphosphine)(+) Complexes-Photophysical, Structural, and Computational Studies. INORGANIC CHEMISTRY, 53 (20). pp. 10854-10861. ISSN 0020-1669, 1520-510X
Full text not available from this repository. (Request a copy)Abstract
The complexes [Cu(I)(POP)(dmbpy)][BF4] (1) and [Cu(I)(POP)(tmbpy)][BF4] (2) (dmbpy = 4,4'-dimethyl-2,2'-bipyridyl; tmbpy = 4,4',6,6'-tetramethyl-2,2'-bipyridyl; POP = bis[2-(diphenylphosphino)-phenyl]ether) have been studied in a wide temperature range by steady-state and time-resolved emission spectroscopy in fluid solution, frozen solution, and as solid powders. Emission quantum yields of up to 74% were observed for 2 in a rigid matrix (powder), substantially higher than for 1 of around 9% under the same conditions. Importantly, it was found that the emission of 2 at ambient temperature represents a thermally activated delayed fluorescence (TADF) which renders the compound to be a good candidate for singlet harvesting in OLEDs. The role of steric constraints within the complexes, in particular their influences on the emission quantum yields, were investigated by hybrid-DFT calculations for the excited triplet state of 1 and 2 while manipulating the torsion angle between the bipyridyl and POP ligands. Both complexes showed similar flexibility within a +/- 10 degrees range of the torsion angle; however, 2 appeared limited to this range, whereas 1 could be further twisted with little energy demand. It is concluded that a restricted flexibility leads to a reduction of nonradiative deactivation and thus an increase of emission quantum yield.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | SENSITIZED SOLAR-CELLS; LIGHT-EMITTING-DIODES; EFFECTIVE CORE POTENTIALS; CU-I COMPLEXES; TRANSFER EXCITED-STATES; COPPER(I) COMPLEXES; ELECTROCHEMICAL-CELLS; MOLECULAR CALCULATIONS; CU(I) COMPLEXES; COORDINATION-COMPOUNDS; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie > Chair of Chemistry III - Physical Chemistry (Molecular Spectroscopy and Photochemistry) > Prof. Dr. Hartmut Yersin |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 08 Aug 2019 12:12 |
| Last Modified: | 08 Aug 2019 12:27 |
| URI: | https://pred.uni-regensburg.de/id/eprint/9342 |
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