Emission studies of poly(N-vinylcarbazole)/poly(3-hexylthiophene) bilayer devices

The absorption, short circuit photocurrent, photoluminescence (PL) and electroluminescence (EL) properties of the bilayer poly(N-vinylcarbazole) (PVK)/poly(3-hexylthiophene) (P3HT) devices are investigated. The properties are compared to the single layer properties of the respective polymers. The studies reveal additive properties in the absorption and photocurrent. The photocurrent spectral response traces the charge carries transport properties across the bilayer, modulated by the absorption from each layer. The PL of the bilayer shows additional features for the excitation range corresponding to the absorption region of PVK. EL from the bilayer is observed and the possibility of exciplex formation at the interface region between the two polymers is speculated. (C) 1997 Published by Elsevier Science B.V.