Solution-processed red organic light-emitting diodes based on phosphorescent iridium(III) complex with isoquinoline derivative as the main ligand

Abstract

Organic Light-Emitting Diodes (OLEDs) have a broad application prospect in the lighting and display fields. Currently, most OLEDs still rely on the vacuum vapor deposition method, with high cost, low productivity and cumbersome operation. In comparison, the solution method is an attractive technology because of its low cost, simple operation and wide range of material choices. The emission wavelength of iridium(III) complexes can be modulated by rationally changing the ligand structure, and a commonly used strategy is to enhance the conjugation effect of the ligand to achieve efficient red phosphorescence. In view of this, an ionic red phosphorescent iridium(III) complex based on isoquinolyl polycyclic derivatives was designed and synthesized, which exhibited red light in dichloromethane, with the maximum emission peak of 610 nm. Subsequently, the corresponding red phosphorescent OLED was prepared using the solution method to explore its photoelectronic properties, with the maximum luminance of 728 cd/m², CE of 0.34 cd/A, PE of 0.16 lm/W, and EQE of 1.92 %, respectively.