Unveiling the influence of the various-membered ring structures on the performance of Ir(iii) complexes: phosphorescent quantum yields and stabilities

Abstract

For the heteroleptic Ir(III) complexes, unveiling the role of ancillary ligands is significant for designing excellent phosphorescent materials. In this investigation, density functional theory (DFT) and time-dependent density functional theory were employed to unveil the influence of various ancillary ligands on the emission wavelengths, radiative/non-radiative decay processes and stabilities. The results indicate that the different various-membered ring structures originating from different ancillary ligands can result in a slight effect on the emission wavelengths, radiative decay rates and the rate-determining steps of temperature-dependent decay processes. However, the reorganization energies can be perturbed efficiently because the vibration forms could be changed by employing different coordination environments. Besides, the stabilities of Ir(III) complexes are also explored by detaching the auxiliary ligand. The stabilities of Ir(III) complexes are closely related to the various-membered ring structures. These results can provide some valuable and useful information for designing excellent heteroleptic Ir(III) complexes as phosphorescent materials in the field of organic light-emitting diodes (OLEDs).