The Study Of OLEDs Based On Europium Complexes

Organic light-emitting diodes (OLEDs) are of great interest, since they efficiently emit light in the visible region and give promising applications in flat display technology. Full color displays require pure red, green and blue emission. However, the broad nature of the luminescent spectra of these organic molecules leads to the poor luminescent purity, which is dull and, thus, not suited for actual display applications.Rare earth complexes are very suitable for full color displays because of their sharp emission bands. In addition, EL efficiency based on rare earth complex is not limited by spin ruling, since their photoluminescence results from the formation of both singlets and triplets of the ligands, and then transferring energy to lanthanide cores. For OLEDs, the development of high-performance red emission is still much in demand compared with both green and blue emission. Eu complexes, which exhibit strong photoluminescence corresponding to the ⁵D₀–⁷F₂ transition of Eu³⁺ ions, appear most attractive in view of red emission ability. In this paper, we have studied the performance of Eu complexes including:Organic electroluminescent devices using Eu(DBM)₃phen as an emitter were fabricated. By doping the Eu complex with PBD and BCP, the EL performance was significantly improved. Different doping ratio and thickness of emitting layer of these devices were studied in detail. The sharp emission at 612 nm, which is a typical luminescence spectrum of Eu3+ ion was measured.Different organic light emitting devices were fabricated by doping a kind of new Eu complex in different host, such as PBD, BCP or CBP. The efficiency of device using CBP as host was better than that of devices using PBD and BCP. Eu complexes with different ligands were used as emitting material in OLEDs. There was great effect by different ligands.The multilayer devices using a kind of new soluble Eu complex as emission material with the structure of ITO/PVK:PBD:Eu complex/PBD/Zn(BTZ)2/Mg:Ag/Ag were fabricated, red light from PLED was achieved and energy transfer from polymer to Eu complex was analyzed.OLEDs using SWNTs in PPV and Eu complex as hole transporting material were fabricated and studied.