Substituent effects on the photophysical and electrochemical properties of iridium(III) complexes containing an arylcarbazolyl moiety

摘要

A series of new heteroleptic cyclometalated iridium(III) complexes containing a 9-(4-(pyridin-2-yl) phenyl)-9H-carbazole molecular framework have been successfully synthesized and characterized. All of the iridium(III) complexes are thermally stable solids and highly efficient electrophosphors. Different substituents, electron-donating group (-CH3) and electron-withdrawing groups (-F, -CF3), were introduced into either the 4- or 5-position of the pyridyl ring in the ligands to verify their influence on the photophysical, electrochemical, photo- and electrophosphoresence properties of these iridium phosphors. Electrophosphorescent OLEDs with outstanding device performance can be fabricated based on the complex bearing a 5-CF3 unit which exhibited a maximum luminance efficiency of approximately 43.2 cd A(-1), corresponding to an external quantum efficiency of approximately 12.6% and a power efficiency of 27.1 lm W-1. (C) 2014 Elsevier Ltd. All rights reserved.