Design of stable platinum(II) complexes exhibited various colors via auxiliary ligand and electron-donating/withdrawing groups: A theoretical investigation

The short operation lifetime is a major factor which hinders the large-scale commercialization of phosphorescent organic light-emitting diodes (OLEDs). Unveiling the intrinsic degradation mechanism of phosphorescent material may be a feasible method for exploring the determined factors of operation lifetime. In this article, the ligand dissociation reactions and phosphorescent quantum yields of various bidentate Pt (II) complexes were investigated by means of the density functional theory (DFT) and time-dependent (TD)-DFT. The calculated results indicate for phosphorescent quantum yields, sulphur heterocycle can facilitate the radiative decay process and suppress the temperature-dependent nonradiative channel. In the aspect of ligand dissociation reactions, the corresponding dissociations of Pt (II) complexes can be effectively avoided via changing the coordinate forms of ligands. In addition, the relationship between geometric tailor and stability, emission color was also taken into account. An analysis of computed results can conclude that the electron-withdrawing and electron-dominating substituents can tune the emissive wavelengths from 477 to 624 nm and cause minor effect on the stability. This investigation could some meaningful information for designing stable Pt (II) complexes.