High-performance pure blue phosphorescent OLED using a novel bis-heteroleptic iridium(iii) complex with fluorinated bipyridyl ligands

Abstract

A novel pure blue phosphorescent emitter FK306 with fluorinated bipyridyl ligands was developed. The Ip level was determined to be 6.3 eV by photoelectron yield spectroscopy (PYS) in the solid state. The photophysical properties of a FK306/mCP film were evaluated. An 11 wt% doped film showed a peak photoluminescence at 454 nm and a high photoluminescent quantum yield (ηPL) of 78 ± 1%. A transient PL decay curve exhibited almost single-exponential decay (98%) with the phosphorescence lifetime (τp) of 1.51 μs at room temperature. A blue OLED with a structure of [ITO (130 nm)/TAPC (40 nm)/FK306 11–20 wt% doped mCP (10 nm)/B3PyPB (50 nm)/LiF (0.5 nm)/Al (100 nm)] was fabricated and evaluated. A high power efficiency of over 30 lm W−1 and an external quantum efficiency of over 17% were observed. The CIE chromaticity diagram (x, y) was evaluated to be (0.16, 0.25), clearly indicating blue emission. These are the first decent performances using a blue emitter with bipyridyl ligands so far.