Shafikov, Marsel Z. and Daniels, Ruth and Pander, Piotr and Dias, Fernando B. and Williams, J. A. Gareth and Kozheynikov, Valery N. (2019) Dinuclear Design of a Pt(II) Complex Affording Highly Efficient Red Emission: Photophysical Properties and Application in Solution-Processible OLEDs. ACS APPLIED MATERIALS & INTERFACES, 11 (8). pp. 8182-8193. ISSN 1944-8244, 1944-8252
Full text not available from this repository. (Request a copy)Abstract
The light-emitting efficiency of luminescent materials is invariably compromised on moving to the red and near-infrared regions of the spectrum due to the transfer of electronic excited-state energy into vibrations. We describe how this undesirable "energy gap law" can be sidestepped for phosphorescent organometallic emitters through the design of a molecular emitter that incorporates two platinum(II) centers. The dinuclear cyclometallated complex of a substituted 4,6-bis(2-thienyl)pyrimidine emits very brightly in the red region of the spectrum (lambda(max) = 610 nm, Phi = 0.85 in deoxygenated CH2Cl2 at 300 K). The lowest-energy absorption band is extraordinarily intense for a cyclometallated metal complex: at lambda = 500 nm, epsilon = 53 800 M-1 cm(-1). The very high efficiency of emission achieved can be traced to an unusually high rate constant for the T-1 -> S-0 phosphorescence process, allowing it to compete effectively with nonradiative vibrational decay. The high radiative rate constant correlates with an unusually large zero-field splitting of the triplet state, which is estimated to be 40 cm(-1) by means of variable-temperature time-resolved spectroscopy over the range 1.7 < T < 120 K. The compound has been successfully tested as a red phosphor in an organic light-emitting diode prepared by solution processing. The results highlight a potentially attractive way to develop highly efficient red and NIR-emitting devices through the use of multinuclear complexes.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | CYCLOMETALATED PLATINUM COMPLEXES; EXTERNAL QUANTUM EFFICIENCY; IRIDIUM(III) COMPLEXES; PHOSPHORESCENT DOPANTS; COORDINATION-COMPOUNDS; ELECTRONIC STATES; EXCITED-STATES; TRIPLET-STATE; LIGANDS; FLUORESCENCE; electroluminescence; near-infrared emission; deep-red luminescence; triplet harvesting; dinuclear platinum complex |
| 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. Alkwin Slenczka |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 21 Apr 2020 10:33 |
| Last Modified: | 21 Apr 2020 10:33 |
| URI: | https://pred.uni-regensburg.de/id/eprint/27518 |
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