We compared the electrical characteristics of polymer, poly(N-vinylcarbazole) (PVK) and small molecule, 4,4'-N,N'-dicarbazole-biphenyl (CBP), N,N'-dicarbazolyl-3,5-benzene (mCP), as host material in white organic light-emitting diodes (OLEDs) fabricated by solution process. In order to obtain the white emission, iridium(III) bis(4,6-difluorophenylpyridinato)-picolinate) (Firpic) and iridium(III) bis(2-phenylquinoline)(acetylaceton) [Ir(pq)(2)acac] were used as blue and red emitting dopant, respectively. As a result, devices with PVK, CBP, and mCP have the max. luminous efficiencies of 10.5 cd/A, 9.8 cd/A, and 4.2 cd/A, respectively.