Electroluminescence of Tb(o-BBA)3(phen) based on an organic–inorganic heterostructure

An organic–inorganic heterostructure device was designed to improve the electroluminescence intensity of terbium ion. In this heterostructure, a mixed solution of (Tb(o-BBA)3(phen)) and poly(N-vinylcarbazole) (PVK) was prepared with a weight ratio of 3:1 which was acted as a hole transporting and emitting layer. A wide band semiconductor zinc sulfide (ZnS) layer was used as an electron transporting and hole blocking layer. Characteristic emissions of terbium ion from the organic–inorganic heterostructure device were observed and the electroluminescence intensity of terbium ion increased abruptly when the driving voltage went beyond 20.5 V. This may be due to a directly impact excitation of terbium ion by hot electrons, accelerated in ZnS layer, and then a recombination with the injected holes. The electroluminescence mechanism of Tb(o-BBA)3(phen)-doped PVK was the charge-carrier trapping process by the dopant molecule according to the emission spectra of PVK and the excitation spectra of Tb(o-BBA)3(phen).