Characterization of electronic structures and spectral properties of the emitting material molecule Cu(I) complexes containing fluorene moiety: a DFT/TDDFT study

摘要

Copper (I) complexes comprise an important class of luminescent materials in organic light emitting diodes (OLED). A Cu(I) complexes, [Cu(POP)(fluPy-Imidazole)]~+ (1), where fluPy-imidazole = 2-(4, 5-dihydro-1H-imidazol-2-yl)-5-(9H-fluoren-2-yl)pyridine, POP= bis[2-diphenylphosphino]-phenyl]ether, was investigated using density functional theory (DFT) and time-dependent density functional theory (TDDFT). The optimized ground structures show that the fluorene ring is not coplanar with the imidazole ring. The HOMO is π character, while the LUMO is π~* orbitals of the Py-imidazole ligands. The lowest lying absorption band of the complexes has the HOMO-1 → LUMO transition configurations resulting in the MLCT/LLCT characters.