Synthesis and characterization of ortho-twisted asymmetric anthracene derivatives for blue organic light emitting diodes (OLEDs)

New ortho-twisted asymmetric anthracene derivatives have been synthesized and characterized. The anthracene derivatives show good thermal stability with high glass transition temperatures and a pure blue emission with a narrow full width at half maximum in a film state (lambda(max) = 454 11 m with 71 nm for 2-(2-methylnaphtathalene-1-yl)-9,10-di(naphthalene-2-yl)anthracene and lambda(max) = 445 nm with 60 nm for 2-(biphenyl-2-yl)-9,10-di(naphthalene-2-yl)anthracene). A multi-layered device using 2-(2-methylnaphtathalene-1-yl)-9,10-di(naphthalene-2-yl)anthracene as an emitting material exhibits a maximum quantum efficiency of 3.61% (power efficiency of 2.15 lm/W, current efficiency of 3.55 cd/A) and blue Commission Internationale de l'Eclairage chromaticity coordinates (x = 0.15, y = 0.13). A fabricated device using 2-(biphenyl-2-yl)-9,10-di(naphthalene-2-yl)anthracene as an emitting material exhibits a maximum quantum efficiency of 3.7% (power efficiency of 2.11 lm/W, current effciency of 3.55 cd/A) and a blue Commission Internationale de l'Eclairage chromaticity coordinates (x = 0.15, y = 0.12). (C) 2011 Elsevier Ltd. All rights reserved.