Phosphorescent Ir(III) complexes bearing the unique PPh2 unit: The electronic structures, optical properties and phosphorescence mechanism from TD-DFT investigation

This paper aims to theoretically design a functionalized Ir(III) complex (bzpy)2Ir(podp) possessing two non-π-electron-conjugated 2-benzyl-pyridyl (bzpy) chromophores and an unique phenolate group substituted by PPh2 unit (podp = phenolate-diphenylphosphine, the PPh2 unit is abbreviated for diphenylphosphine ligand), on the basis of the benchmark specie (ppy)2Ir(podp) (ppy = 2-phenylpyridine). Via the theoretical results, the radiative rate constant, the spin-orbital coupling (SOC) matrix element, ΔE(S1 − T1), and the square of the SOC matrix element are all approximately measured. It is intriguing to note that new complex exhibits its emission maxima at 558 nm with quality improvement. Finally, on the information mentioned, a reformative green-PhOLED utilizing both the complexes are designed and evaluated tentatively.