Red phosphorescent organic light-emitting diodes (PhOLEDs) based on a heteroleptic cyclometalated Iridium (III) complex

Highly efficient red-emitting Phosphorescent Organic Light-Emitting Diodes (PhOLEDs) based on a neutral vacuum-sublimatable heteroleptic iridium (III) complex have been designed and studied. Heteroleptic complex Ir(piq)2(acac) was prepared in one step with acetylacetone (acac) as the ancillary ligand. Electronic and spectroscopic properties of Ir(piq)2(acac) were investigated by UV-visible absorption, fluorescence spectroscopy and cyclic voltammetry. Electrophosphorescent devices comprising Ir(piq)2(acac) as dopant of TCTA exhibited outstanding electroluminescence performance with a current efficiency of 10.0 cd A−1, a maximum power efficiency of 7.2 lm W−1 and a maximal brightness of 3540 cd m−2 was reached at 8.0 V. CIE coordinates close to the standard red of the national television system committee were obtained (0.67, 0.33).