Energy transfer from organics to rare-earth complexes

Energy transfer from several semiconducting organic molecules and polymers to rareearth complexes in the form of spin-cast films is reported. Energy transfer is observed in poly(N-vinylcarbazole) (PVK) films doped with various europium and samarium complexes. Polystyrene films containing the hole-transporting organic molecule 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD) and the electron-transporting molecule N,N'-bis(3-methylphenyl)-N,N-diphenylbenzidine also show energy transfer to the europium complexes, but not to the samarium ones. We show that energy transfer from PBD to the europium complexes is more efficient than from PVK. These films are semiconducting and easy to process, so they are candidates for monochromatic light-emitting diodes. (C) 2002 American Institute of Physics.