Are Triphenylamine‐Functionalized or Carbazole‐Functionalized Iridium Complexes the More Effective Phosphorescent Materials? A Theoretical Perspective

The ground and excited states, charge injection/transport, and phosphorescence properties of eleven carbazole‐ and triphenylamine‐functionalized Ir III complexes were investigated by using the DFT method. By analyzing the spin–orbit coupling (SOC) matrix elements, radiative decay rate constants k r , and the electronic structures and energies at the ${{\rm{S}}_{\rm{0}}^{{\rm{opt}}} }$ and ${{\rm{T}}_{\rm{1}}^{{\rm{opt}}} }$ states, it was possible to rationalize the order of the experimental phosphorescence quantum yields of a series of Ir III complexes and to predict that [Ir(Nph‐2‐Cz‐tz) 3 ] has a higher phosphorescence quantum yield than [Ir(TPA‐tz) 3 ] (TPA=triphenylamine, tz=thiazolyl, Cz=carbazole, Nph= N ‐phenyl). Carbazole‐functionalized Ir III complexes were shown to be efficient phosphorescent materials that have not only fast but also balanced electron/hole‐transport performance as well as high phosphorescence quantum yields. The phosphorescence emission spectra can be modulated by modifying or replacing a pyridyl substituent.