Theoretical studies of electronic structures, absorption and emission spectra in cyclometalated phenylpyridine Ir(III) complex and its derivatives using density functional theory

The ground-state and electronic spectra in the Ir(III) complex Ir(ppy)3 [where ppy = 2-phenylpyridine], an important phosphorescent material, and its derivatives are studied using density functional theory (DFT) B3LYP/LanL2dz in programme Gaussian 98. The effects of substituted groups on energies, gaps of HOMO–LUMO, absorption and emission spectra are discussed. It is found that electron-withdrawing substituent (–CN) makes both orbital energies and gaps of HOMO–LUMO decrease, leads to both absorption and emission spectra red-shift whereas electron-releasing substituent (–OCH3) makes orbital energies increase and gaps of HOMO–LUMO, absorption and emission spectra relatively unvaried.