[Emission mechanism in the Tb complex doped PVK system].

Excitation and photoluminescence (PL) spectra of the mixture terbium complex and PVK were investigated. The excitation spectrum of Tb complex dispersed PVK film is very similar to that of the pure PVK film, indicting that energy transfer occurs from PVK to Tb complex. For the overlap between the excitation spectrum of Tb complex dispersed PVK film and the PL spectrum of PVK film is very little, the ratio of occurrence for Förester energy transfer is very little. The emission of Tb3+ mainly comes from the excited ligand, which comes from the ligand capture of electron-hole pairs. In the electroluminescence (EL) spectra, the emission of PVK is completely restrained and only emission of Tb3+ is occured, which origins from the different mechanism in comparison with photoluminescence.