A more steric hindrance pentacene derivative, 6,13-di-(3,5-diphenyl) phenylpentacene (PDT) is synthesized in this experiment. And this manuscript presents the red emission organic light-emitting devices based on tris-(8-hydroxy- quinolinato) aluminum (Alq(3)) co-doped with 6,13-di-(3,5-diphenyl) phenylpentacene (PDT), and 5,6,11,12-tetraphenylnaphthacene (rubrene). By measuring and analyzing the intensity of red emission and Commission Internationale de l'Eclairage (CIE) coordinates of the devices with different rubrene concentrations and thicknesses of active layer, an optimized structure of [ITO/TPD (50 nm)/Alq(3): 3mol%PDT:1mol%rubrene(60 nm)/Bphen(25 nm)/LiF/Al] is obtained. The experimental results suggest that rubrene assists energy transfer from Alq(3) to PDT in composite of Alq(3):PDT:rubrene, which results in relatively pure red emission. A red emission with chromaticity coordinates (x = 0.61, y = 0.37) is also obtained with the emitting layer of [Alq(3):3 mol% PDT:1 mol% rubrene] within the driving current density range of 12-120 mA/cm(2). A maximum luminance efficiency of 2.4 cd/A is measured at current density of 120 mA/cm(2) and high brightness of 2894 cd/m(2). (c) 2010 Elsevier B.V. All rights reserved.