Synthesis, Characterization And Photoemission Performance Based On Bifunctional Rare Earth Complexes

Organic light-emitting planar displays have the advantages of low-voltage driving, high luminosity, high efficiency and large-area color display as a novel display technique, and have been investigated hotspot in today electroluminescent field. But as a result of efficiency, stability and cost, it can not meet demand in practicability cosmically.For most light-emitting materials, the method of improving the luminescence efficiency of electroluminescent materials is how to improving electron injection and transmission of its carriers, and carry out the high efficient composition of two carriers. A perfect design project is that light-emitting materials are not only luminous but also have high electron and hole injection/ balance performance, only in this way, simple device technics can meet demand in practicability. Rare earth (RE) complexes show the characteristics of sharp-band emissions, high efficiency and no influence on the emissions color of the central rare earth metal ion with the design of ligands, so they have been ideal light-emitting materials in colorized flat displays.In this paper we have designed and synthesized a novel carboxylic acid ligand (L) with carbazole group, and also synthesized four rare earth complexes (EuL3, TbL3, SmL3, DyL3). We have characterized the ligand and the four rare earth complexes by IR, Uv-vis spectra, 1HNMR spectra and elemental analysis. We figure out the triplet energy level of ligand based on phosphorescence spectra of GdL3 complex, and analyse the relation between triplet energy level of ligand and lowest excited state energy level of Eu3+,Tb3+,Sm3+,Dy3+, summarize why TbL3 and DyL3 can not luminescent and EuL3 and SmL3 only emit weak fluorescence. Because of their weak fluorescence, they are hopeful in organic photovoltaic devices.On the other hand,we have studied Re(CO)3(dppz)Cl (phosphorescence complex) in respect of electrospinning and have characterized Re(CO)3(dppz)Cl soild, pure PVP nanofiber and mixture nanofibers by IR, it is found that there is weak reciprocity between PVP and Re(CO)3(dppz)Cl .From the emission spectrum of liquid Re(CO)3(dppz)Cl, We have found that there is a emission peak at 500nm, which is assigned to the dπ(Re)→π* MLCT transition.