Improved photoluminescence performance from polymer nanofibers doped with phosphorescent Ir(III) complex

Abstract In the present paper, an Ir(III) complex of Ir(PD)(PBT)2 was synthesized, where PD and PBT stand for pentane-2,4-dione and 2-phenylbenzo[d]thiazole, respectively. The molecular identity of Ir(PD)(PBT)2 was confirmed by its single crystal. It was found that Ir(PD)(PBT)2 belonged to monoclinic system with two molecules in each unit cell. Theoretical calculation on Ir(PD)(PBT)2 suggested that the onset electronic transitions owned a mixed character of metal-to-ligand-charge-transfer and ligand-to-ligand-charge-transfer. By doping this complex into a polymer matrix of poly(vinylpyrrolidone) (PVP), the photophysical features of the resulting composite fibers were discussed and compared with those of Ir(PD)(PBT)2 solution. It was found that the immobilization in PVP host could improve the photoluminescence performance by restraining the excited state geometric relaxation, showing higher emission energy, longer excited state lifetime and better photostability.