A theory study based on DFT/TD-DFT for a series of Ir(III) complexes with the low-efficiency roll-off and the high-inter-system crossover rate properties

This study employs density functional theory (DFT) and time-dependent density functional theory (TD-DFT) to investigate a series of cyclometallated Ir(III) complexes for their application as OLED light-emitting materials, including (dtp)(2)Ir(dpm), (mmpyp)(2)Ir(dpm), (dtp)(2)Ir(tpip), (mmpyp)(2)Ir(tpip), (dtp)(2)Ir(pic), and (mmpyp)(2)Ir(pic). Their geometries, frontier molecular orbital properties, ionization potential, electron affinity, absorption and emission spectra, and spin-orbit coupling properties have been analyzed respectively. Through comparison, we have identified complexes with reduced efficiency roll-off and enhanced k(ISC).