A new rare earth complex Tb（p-CIBA）3phen was synthesized and introduced into organic tight emitting devices （OLEDs） as emitting material. The Tb（p-CIBA）3phen was doped into PVK to improve the filmforming and hole-transporting property. Two kinds of devices were fabricated. The device structure is as the following. Single-layer device： ITO/PVK： Tb （p-CIBA） 3 phen /LiF/Al; double-layer device： ITO/PVK： Tb（p-CIBA）3phen/AIQ/LiF/AI. The performances of both devices were investigated carefully. We found that the emission of PVK was completely restrained,and only the green emission was observed from the electroluminescence. The full width at half maximum （FWHM） was less than 10 nm. The highest EL brighthess of the single-layer device is 25.4 cd/cm^2 at a fixed bias of 18 V,and the highest EL brightness of the double-layer device reaches 234.8 cd/cm^2 at a voltage of 20 V.
A novel rare earth complex Eu0 5La0.5 （TRA）3phen, displaying electroluminescent property, was synthesized, and monolayer and double-layer devices were fabricated by doping it into poly N-vinylcarbazole. The characteristics of these optimized devices were investigated, and the emitting mechanism was explained through the energy band diagram. Optimized double-layer devices with a turn-on voltage of 6.5 V were achieved. At the current density of 68.48 mA·cm^- 2, the maximum brightness and the current efficiency of the device reached 238.4 cd·m^-2 and 0.35 cd·A^-1, respectively.
A rare earth complex TbY （o-MBA）6（phen）2 was synthesized, which was first used as an emitting material in electroluminescence. By doping it into the conjugated polymer PVK, single-layer and double-layer devices were fabricated with structures： device A ： ITO/PVK ： rpDY （o-MBA）6（phen）2/LiF/Al; B ： ITO/PVK ： rpDY （o-MBA）6（phen）2/AIQ/LiF/Al; C： ITO/PVK： TbY（o-MBA）6（phen）2/BCP/AlQ/LiF/Al. The characteristics of these devices were investigated. For single-layer and double-layer devices, the emission of PVK was completely restrained, and only the green emission from rpD^3＋ was observed in electroluminescence. The above mentioned observation is attributed to the different mechanism of electroluminescence and photoluminescence. In photoluminescence process, the energy of Tb complex may come from PVK through Forster energy transfer process, while in electroluminescence process direct sequential charge trapping appeares to be the main operating mechanism. From the optimized device B, brightly green emission can be obtained, and the highest EL brightness of the device reaches 213 cd·m^-2 at 14 V.
