The photoluminescence properties of one europium complex Eu(TENB)(3)Phen (TFNB = 4,4,4-trifluoro-1-(naphthyl)-1,3-butanedione, Phen = 1,10-phenanthroline) doped in a hole-transporting material CBP (4,4'-N,N'-dicarbazole-biphenyl) films were studied. A series of organic light-emitting devices (OLEDs) using Eu (TENB)(3)Phen as the emitter were fabricated with a multilayer structure of indium tin oxide, 250 Omega/square)/TPD (N,N'-diphenyl-N,N'-bis(3-methyllphenyl)-(1,1'-biphenyl)-4,4'-cliamine, 50 nm)/Eu(TENB)(3)phen (x): CBP (4,4'-N,N'-dicarbazole-biphenyl, 45 nm)/BCP (2,9-dimethyl-4,7-diphenyl-1,10 phenanthroline. 20 nm)/AIQ (tris(8-hydroxy-quinoline) aluminium, 30 nm)/LiF (1 nm)/Al (100 nm), where x is the weight percentage of Eu(TENB)(3)phen doped in the CBP matrix (1-6%). A red emission at 612 nm with a half bandwidth of 3 nm, characteristic of Eu(III) ion, was observed with all devices. The device with a 3% dopant concentration shows the maximum luminance up to 1169 cd/m(2) (18 V) and the device with a 5% dopant concentration exhibits a current efficiency of 4.46 cd/A and power efficiency of 2.03 lm/W. The mechanism of the electroluminescence was also discussed. (C) 2010 Elsevier B.V. All rights reserved.