White light-emitting polymer device based on poly(3-hexylthiophene) (P3HT) block copolymer

Abstract

White polymer light-emitting diode (WPLED) is demonstrated using block copolymer of poly(N-vinylcarbazole) (PVK) and poly(3-hexylthiophene) (P3HT) as an emitting layer, which obtains (0.348, 0.333) of the 1931 Commission Internationale de 1’Eclairage (CIE) chromaticity. The Wide band gap of PVK in the short wavelength region and the low band gap of P3HT part in the long wavelength region in this block copolymer would give a good contribution for the whole-range light emission with its ability to self-structure into regular and ordered microphases. The overlap between the absorption of P3HT and the emission of PVK superimposes well and provides a good condition for resonance energy transfer from PVK to P3HT which shows white emission. The maximum luminance is ~130 cd/m2 with maximum efficiency of ~0.006 cd/A. Even though the efficiency of this PVK-P3HT block copolymer is low, this result indicates a new possibility to realize white light emitting by block copolymer.