A Configurationally Confined Thermally Activated Delayed Fluorescent Two-Coordinate CuI Complex for Efficient Blue Electroluminescence.
Angew Chem Int Ed Engl
; 62(7): e202217195, 2023 Feb 06.
Article
em En
| MEDLINE
| ID: mdl-36542446
ABSTRACT
Thermally activated delayed fluorescence (TADF) from linear two-coordinate coinage metal complexes is sensitive to the geometric arrangement of the ligands. Herein we realize the tuning of configuration from coplanar to orthogonal gradually by variation of substituents. In a complex with confined twist configuration, its blue emission peaking at 458â
nm presents a high ΦPL of 0.74 and a short τTADF of 1.9 µs, which indicates a fast enough kr,TADF of 3.9×105 â
s-1 and a depressed knr of 1.4×105 â
s-1 . Such outstanding luminescent properties are attributed to the proper overlap of HOMO and LUMO on CuI d orbitals that guarantees not only small ΔEST but also sufficient transition oscillator strength for fast k r , S 1 ${{k}_{{\rm r},{{\rm S}}_{1}}}$ . Vacuum-deposited blue OLEDs with either doped or host-free emissive layer present external quantum efficiencies over 20 % and 10 %, respectively, demonstrating the practicality of the configurationally confined strategy for efficient linear CuI TADF emitters.
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MEDLINE
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Ano de publicação:
2023
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Article