Schinabeck, Alexander and Rau, Nicholas and Klein, Marius and Sundermeyer, Joerg and Yersin, Hartmut (2018) Deep blue emitting Cu(i) tripod complexes. Design of high quantum yield materials showing TADF-assisted phosphorescence. DALTON TRANSACTIONS, 47 (47). pp. 17067-17076. ISSN 1477-9226, 1477-9234
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In a previous investigation, it was shown that [Cu(tpym)(PPh3)]PF(6)1 with tpym = tris(2-pyridyl)methane represents a deep blue emitter ((max) = 466 nm) though with a low emission quantum yield phi(PL) if doped in a polymer (7%) or dissolved in a fluid solvent (<<1%). In this study, we present new tripod compounds with sterically demanding ligands: [Cu(tpym)(P(o-tol)(3))]PF(6)2 and [Cu(tpym)(P(o-butyl-ph)(3))]PF(6)3 with P(o-tol)(3) = tris(ortho-tolyl)phosphine and P(o-butyl-ph)(3) = tris(ortho-n-butylphenyl)phosphine. These compounds show high emission quantum yields even in a fluid solution (dichloromethane) reaching a benchmark value for 3 of phi(PL) = 76%. This becomes possible due to the specific design of rigidifying the complexes. Importantly, the deep blue emission color is maintained or even further blue shifted to (max) = 452 nm (compound 3 powder). Compound 2 is characterized photophysically in detail. In particular, it is shown that the lowest excited triplet state T-1 experiences very efficient spin-orbit coupling (SOC). Accordingly, the phosphorescence decay rate is as large as 5 x 10(4) s(-1) (20 s) belonging to the fastest T-1 S-0 transition values (shortest decay times) reported so far. Investigations down to T = 1.5 K reveal a large total zero-field splitting (ZFS) of 7 cm(-1) (0.9 meV). Although thermally activated delayed fluorescence (TADF) grows in at T 160 K, the phosphorescence of 2 still dominates (60%) over TADF (40%) at ambient temperature. Thus, the compound represents a singlet harvesting-plus-triplet harvesting material, if applied in an OLED.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | ACTIVATED DELAYED FLUORESCENCE; COPPER(I) COMPLEXES; IRIDIUM COMPLEXES; TRIPLET EMITTERS; BASIS-SETS; EMISSION; STATE; SINGLET; DIODES; EFFICIENCY; |
| 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: | 02 Oct 2019 12:17 |
| Last Modified: | 02 Oct 2019 12:17 |
| URI: | https://pred.uni-regensburg.de/id/eprint/13339 |
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