Shafikov, Marsel Z. and Suleymanova, Alfiya F. and Czerwieniec, Rafal and Yersin, Hartmut (2017) Design Strategy for Ag(I)-Based Thermally Activated Delayed Fluorescence Reaching an Efficiency Breakthrough. CHEMISTRY OF MATERIALS, 29 (4). pp. 1708-1715. ISSN 0897-4756, 1520-5002
Full text not available from this repository. (Request a copy)Abstract
A design strategy for the development of Ag(I)-based materials for thermally activated delayed fluorescence (TADF) is presented. Although Ag(I) complexes usually do not show TADF, the designed material, Ag(dbp)(P-2-nCB) [dbp = 2,9-di-n-butyl-1,10-phenanthroline, and P-2-nCB = nido-carborane-bis(diphenylphosphine)], shows a TADF efficiency breakthrough exhibiting an emission decay time of tau(TADF) = 1.4 mu s at a quantum yield of = Phi(PL) = 100%. This is a consequence of three optimized parameters. (i) The strongly electron donating negatively charged P-2-nCB ligand destabilizes the 4d orbitals and leads to low-lying charge (CT) states of MLL'CT character, with L and L' being the two different ligands, thus giving a small energy separation between the lowest singlet S-1 and triplet T-1 state of Delta E(S-1-T-1) = 650 cm (-1) (80 meV). (ii) The allowedness of the S-1 -> S-0 transition is more than 1 order of magnitude higher than those found for other TADF metal complexes, as shown experimentally and by time-dependent density functional theory calculations. Both parameters favor a short TADF decay time. (iii) The high quantum efficiency is dominantly related to the rigid molecular structure of Ag(dbp)(P-2-nCB), resulting from the design strategy of introducing n-butyl substitutions at positions 2 and 9 of phenanthroline that sterically interact with the phenyl groups of the P-2-nCB ligand. In particular, the shortest TADF decay time of tau(TADF) = 1.4 mu s at a Phi(PL)value of 100%, reported so far, suggests the use of this outstanding material for organic light-emitting diodes (OLEDs). Importantly, the emission of Ag(dbp)(P-2-nCB) is not subject to concentration quenching. Therefore, it may be applied even as a 100% emission layer.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | LIGHT-EMITTING-DIODES; CYCLOMETALATED IRIDIUM COMPLEXES; RESOLUTION OPTICAL SPECTROSCOPY; COPPER(I) HALIDE-COMPLEXES; LIGAND CHARGE-TRANSFER; PHOTOPHYSICAL PROPERTIES; ELECTROCHEMICAL-CELLS; SILVER(I) COMPLEXES; CU(I) COMPLEXES; EXCITED-STATES; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie 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: | 14 Dec 2018 13:01 |
| Last Modified: | 20 Feb 2019 11:09 |
| URI: | https://pred.uni-regensburg.de/id/eprint/369 |
Actions (login required)
 |
View Item |
