Emission of white light from 2-(2′-hydroxyphenyl) benzothiazole in polymer electroluminescent devices

Single-layer polymer devices that emit bright light from dye dispersed in the polymer matrix are fabricated. The active layer consists only of one polymer layer sandwiched between two electrodes-indium tin oxide and Mg:Ag. 2-(2-hydroxyphenyl) benzothiazole (HBT), a UV absorbent, is synthesized and exhibits bright blue-green fluorescence. Bright white emission is observed when the concentration of the dye in poly(N-vinylcarbazole) (PVK) polymer matrix is adjusted appropriately. The single-layered polymer blended electroluminescent (EL) device (ITO/polymer/Mg/Ag) has a relatively low driving voltage of 8 V. The EL spectrum includes three emission peaks at 420, 530 and 600 nm, representing deep blue, green and red light, respectively. The chromaticity coordinates, as specified by the Commission Internationale de l'Eclairage are (0.34, 0.36).