Solution-processed organic light-emitting diodes based on yellow-emitting cationic iridium(III) complexes bearing cyclometalated carbene ligands

Abstract

Two new cationic iridium complexes bearing cyclometalated carbene ligands have been prepared, and the photophysical and electrochemical properties have been investigated. In degassed acetonitrile solutions, these complexes exhibit yellow light emission with peaks at 591 and 579 nm, respectively. Both photophysical properties and quantum chemical calculations indicate that photoluminescence of these complexes are mainly from triplet charge-transfer excited states. Solution-processed organic light-emitting diodes based on these complexes exhibit yellow electroluminescences with the maximum current efficiencies of 17.42 and 6.36 cd A−1 and Commission Internationale d’Énclairage(x, y) coordinates (CIEx,y) of (0.47, 0.51) and (0.51, 0.47), respectively.