Theoretical insight into the electronic structures and photophysical properties of two series of iridium(III) complexes with different substitute groups or substituent position

The electronic structures and photophysical properties of two series of iridium(III) complexes have been investigated. Complexes 1b and 2b have the smallest IP values and the lowest hole injection energy barriers. The lowest energy absorptions for all studied complexes are assigned as the transition configurations of HOMO -> LUMO. The calculated phosphorescence emission wavelength of complex 1 is in good agreement with the experiment value. The conclusion can be drawn that the different substituent group and substitution positions has obvious effect on the electronic structure and photophysical properties. The theoretical investigation will be useful to design new organic light-emitting diodes (OLEDs) material.