Theoretical study on phosphorescence efficiency and color tuning from orange to blue-green of Ir(III) complexes based on substituted 2-phenylimidazo[1,2-a]pyridine ligand
Copyright © 2010 Wiley Periodicals, Inc.
| Publié dans: | Journal of computational chemistry. - 1984. - 32(2011), 6 vom: 30. Apr., Seite 1033-42 |
|---|---|
| Auteur principal: | |
| Autres auteurs: | , , , |
| Format: | Article en ligne |
| Langue: | English |
| Publié: |
2011
|
| Accès à la collection: | Journal of computational chemistry |
| Sujets: | Journal Article 2,5-dipicryl-1,3,4-oxadiazole Ligands Organometallic Compounds Oxadiazoles Trinitrobenzenes Iridium 44448S9773 |
| Résumé: | Copyright © 2010 Wiley Periodicals, Inc. The geometrical structures, phosphorescence quantum yields, and electroluminescence (EL) efficiency of six iridium(III) complexes containing 2-phenylimidazo[1,2-a]pyridine ligand are investigated by density functional theory (DFT), which show a wide color tuning of photoluminescence from orange (λ(em) = 550 nm) to blue-green (λ(em) = 490 nm). The calculated results shed some light on the reasons of the remarkably manipulated excited-state and EL properties through substitution effect. The Mulliken charge calculation reveals that attached -CF(3) groups on phenyl and imidazo[1,2-a]pyridine (impy) moieties (4) can make both of them as electron-deficient region, which will lead to the contraction of the whole coordination sphere and strengthen the metal-ligand interaction. While attaching two -CF(3) groups on phenyl ring can make it more electron-deficient, which will induce electron transferring from acac and impy fragment to phenyl ring, and also result in the contracted structure. The largest metal-to-ligand charge transfer ((3)MLCT) character and the smaller S(1)-T(1) energy gap (ΔE(S(1)-T(1))) value increase the emission quantum yields of 4 and 6 than other complexes. For EL efficiency, because of the similar highest occupied molecular orbital (HOMO) levels of 4 and 6 to that of holes injection material poly(N-vinylcarbazole) (PVK) and the larger dipole moments, majority hole will be accumulated on the HOMO of 4 and 6. Combination with the lower lowest unoccupied molecular orbital energy levels compared with PVK, the recombination zones of 4 and 6 can be well confined within emitting material layer (EML) and lead to the higher EL efficiency |
|---|---|
| Description: | Date Completed 14.06.2011 Date Revised 21.11.2013 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1096-987X |
| DOI: | 10.1002/jcc.21682 |