Solution-processable iridium phosphors for efficient red and white organic light-emitting diodes with low roll-off

Abstract

A new red phosphorescent material Ir(dmppm)₂(dmd), which is a pyrimidine-based iridium(III) complex, has been synthesized and successfully used to fabricate solution-processed red and white organic light-emitting diodes (OLEDs). Due to its excellent solubility in common organic solvents and its good compatibility with the host material, a record current efficiency of 27.2 cd A⁻¹ so far with satisfactory Commission International de l'Eclairage (CIE) coordinates of (0.60, 0.40) has been achieved for partially solution-processed red OLEDs by using Ir(dmppm)₂(dmd) as a dopant. Furthermore, the fabricated two-component “warm-white” OLEDs based on the Ir(dmppm)₂(dmd) red emitter demonstrate a maximum current efficiency of 28.9 cd A⁻¹, which can meet the call for physiologically-friendly indoor illumination.