Exciplex electroluminescence of indium-tin-oxide glass (ITO)/poly(N-vinylcarbazole)(PVK):N,N'-diphenyl-N,N'-bis(3-methylphenyl) -[1,1'-biphenyl]-4,4'-diamine(TPD): 2,5-bis (5-tert-butyl-2-benzoxazolyl) thiophene (BBOT)/Al devices have been investigated in comparison with ITO/PVK:BBOT/Al device. While the ITO/PVK:BBOT/Al device shows emission dominated by exciplex interaction of PVK with BBOT, the ITO/PVK:TPD:BBOT/Al devices show emission color adjustable by the hybrid exciplex interaction of TPD with BBOT, and this exciplex becomes the primary recombination center at a critical TPD doping concentration. The device efficiency can be improved markedly by incorporating hole transporting poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS) and electron transporting 2.9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP)/tris-(8-hydroxyquinoline) aluminum (Alq(3)) layers in a structure of ITO/PEDOT:PSS/PVK:TPD:BBOT/BCP/Alq(3)/Al. (C) 2003 Elsevier Science B.V. All rights reserved.