Highly efficient single-layer white polymer light-emitting devices employing triphenylamine-based iridium dendritic complexes as orange emissive component

Abstract

New triphenylamine-based iridium(III) dendritic complexes are demonstrated as active components for white polymer light-emitting diodes (WPLEDs). Initially the orange PLEDs are fabricated through dispersing the dendrimers into PVK in the presence of an electron-transport material 2-tert-butylphenyl-5-biphenyl-1,3,4-oxadiazole (PBD). High performance of orange PLEDs is acquired by use of the low-conductivity anode buffer layer P8000, with the maximum current/power/external quantum efficiencies of 52.4 cd A⁻¹/21.6 lm W⁻¹/21.0%. Based on the excellent performance of the orange PLEDs, single-layer white polymer light-emitting devices (WPLEDs) are fabricated by double-doping sky-blue emitter iridium(III) bis(2-(4,6-difluorophenyl)-pyridinato-N,C²)picolinate (FIrpic) and the orange iridium dendrimers. These WPLEDs achieve the maximum current/power/external quantum efficiencies of 37.0 cd A⁻¹/19.4 lm W⁻¹/18.5%, which are among the highest efficiencies for dual-color WPLEDs ever reported. This work presents a premiere attempt on applying dendritic phosphor in highly efficient all-phosphor WPLEDs and a step forward to panchromatic application of Ir(III) dendrimers.