Luminescent properties of novel bis-cyclometalated iridium(III) complexes bearing methoxy-substituted dibenzoylmethanate ligands

ABSTRACT

Novel phosphorescent bis-cyclometalated iridium(III) complexes bearing methoxy-substituted dibenzoylmethanate ligands were synthesi-zed, and the effect of the methoxy groups on their luminescent properties was investigated. The developed complexes exhibited yellow emission in dichloromethane, whereas they showed rigidochromic behavior of photoluminescence (PL) in PMMA films to afford green emission. The PL quantum yields in both solutions and films decreased according to the increase in the number of the methoxy groups. Theoretical calculations indicated that the radiative relaxation is attributed to metal-ligand-to-ligand charge transfer transition. A white OLED employing one of the complexes as a green component exhibited an excellent color rendering index of 79.

KEYWORDS:

• Organic light-emitting diode
• Iridium(III) complex
• Aromatic diketonate ligand
• Phosphorescence
• White OLED
• Color rendering index

Acknowledgement

This work was partially supported by a Grant-in-Aid for Scientific Research on Innovative Areas “New Polymeric Materials Based on Element-Blocks (No. 2401)” (JSPS KAKENHI Grant Number JP15H00759)