Polymer-Based Blue Electrophosphorescent Light-Emitting Diodes Using a Bisorthometalated Ir(III) Complex as the Triplet Emitter

Polymer-based blue electrophosphorescent light-emitting diodes are reported by doping bisorthometalated (phosphine)cyanoiridium(III) complex Ir(ppy) 2 P( n -Bu) 3 CN (ppy = 2-phenylpyridine, P( n -Bu) 3 = tri- n -butylphosphine) in poly(vinylcarbazole) (PVK) as the source of emission. The (phosphine)cyanoiridium(III) complex shows sky blue emission with two peaks at 467 and 496 nm originating from an admixture of triplet metal-to-ligand charge-transfer and ligand-centered states. The PL and EL spectra of an Ir(ppy) 2 P( n -Bu) 3 CN-doped PVK film and device exhibited no emission from PVK, indicating that the energy transfer from PVK to Ir(ppy) 2 P( n -Bu) 3 CN is efficient. A maximum external quantum efficiency (η ex ) of 1.45% and power efficiency (η p ) of 0.99 lm/W were achieved at 13 and 6 mA/cm 2 at a 10 wt % doping concentration, respectively.