This paper reported an effective synthesis of novel copolymers containing terbium complexes by free radical copolymerization of 9-vinylcarbazole, methyl methacrylate and terbium-methacrylate complex in DMF with AIBN as initiator. The resulting copolymers are soluble and can be cast into transparent films with good mechanical flexibility. The structure and composition of the copolymers were confirmed by FT-IR, gel permeation chromatography, NMR and elemental analysis. These copolymers have the M_w value of 20000～50000 and exhibit relatively broad polydispersity index as determined by GPC. The photoluminescent and electroluminescent properties of the copolymers containing terbium complex were studied in solid state as a thin film and a single layer polymer light-emitting diode (PLED). The device exhibited characteristic sharp green electroluminescence when forward bias was applied. The turn-on voltage is about 15 V. A maximum brightness of 16 cd/m² with a luminous efficiency of about 0.024 lm/W was achieved from this single-layer PLED based on the multi-functional copolymer P1. EL spectra of the devices showed that the emissions were mainly from the corresponding lanthanide-complex units, instead of carbazole groups of the copolymers. It is suggested that the carbazole groups in P1 serve as hole-transport material while electron transfer may occur through the lanthanide-containing moieties of the same copolymer.

Key words: terbium, complex, copolymer, photoluminescence, electroluminescence