Theoretical study of electronic structures and opto-electronic properties of iridium(III) complexes containing benzoxazole derivatives and different ancillary β-diketonate ligands

Quantum-chemical method is used to study the electronic structures and opto-electronic properties of six cyclometalated iridium(III) complexes having a general formula (C^N)2Ir(LL′) [where C^N is a cyclometalating ligand (namely 2-phenyl benzoxazolato (pbo), 2-(4-chlorophenyl) benzoxazolato (cpbo), 2-phenyl-5-chlorobenzoxazolato (pcbo), 2-(3,5-difluorophenyl) benzoxazole (dfpbo)] and LL′ is an ancillary β-diketonate ligand (namely acetylacetonate (acac), dibenzoylmethanate (dbm) and 1,1,1,5,5,5-hexafluoroacetyl acetonate (hfacac). These complexes (pbo)2Ir(acac) (1), (cpbo)2Ir(acac) (2), (pcbo)2Ir(acac) (3), (dfpbo)2Ir(acac) (4), (dfpbo)2Ir(dbm) (5) and (dfpbo)2Ir(hfacac) (6) are based on benzoxazole derivatives and different β-diketonate ligands. The mobility of hole and electron are studied computationally based on the Marcus theory. Calculations of ionization potentials (IPs) and electron affinities (EAs) are used to evaluate the injection abilities of holes and electrons into these complexes. The results indicate that these complexes can be used as an electroluminescent materials.