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Lookup NU author(s): Professor Thomas Penfold
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
A novel dinuclear platinum(II) complex featuring a ditopic, bis-tetradentate ligand has been prepared. The ligand offers each metal ion a planar O^N^C^N coordination environment, with the two metal ions bound to the nitrogen atoms of a bridging pyrimidine unit. The complex is brightly luminescent in the red region of the spectrum with a photoluminescence quantum yield of 83% in deoxygenated methylcyclohexane solution at ambient temperature, and shows a remarkably short excited state lifetime of 2.1 μs. These properties are the result of an unusually high radiative rate constant of around 4 Å~ 105 s–1, a value which is comparable to that of the very best performing Ir(III) complexes. This unusual behaviour is the result of efficient thermally activated reverse intersystem crossing, promoted by a small singlet–triplet energy difference of only 69 ± 3 meV. The complex was incorporated into solution-processed OLEDs achieving EQEmax = 7.4 %. We believe this to be the first fully evidenced report of a Pt(II) complex showing thermally activated delayed fluorescence (TADF) at room temperature, and indeed of a Pt(II)-based delayed fluorescence emitter to be incorporated into an OLED.
Author(s): Pander P, Daniel R, Zaytsev AV, Horn A, Sil A, Penfold TJ, Williams JAG, Kozhenvbikov VN, Dias FB
Publication type: Article
Publication status: Published
Journal: Chemical Science
Online publication date: 22/03/2021
Acceptance date: 19/03/2021
Date deposited: 23/03/2021
ISSN (print): 2041-6520
ISSN (electronic): 2041-6539
Publisher: Royal Society of Chemistry
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