The bilayer organic light-emitting diode(OLED) with a blue fluorescent lanthanum complex, tris(1-phenyl-3-methyl-4-isobutyryl-5-pyrazolone)-(2,2′-dipyridyl) lanthanum [La(PMIP) 3(Bipy)], as a light emitting material and N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine(TPD) as a hole transporting material emits bright green light instead of blue light. The data of the absorption, the photoluminescence(PL) and the photoluminescence excitation(PLE) spectra of TPD, La(PMIP) 3(Bipy) and the mixture of TPD and La(PMIP) 3(Bipy)(molar ratio 1∶1) prove that the electroluminescent emission originates from the exciplex on the interface between TPD and La(PMIP) 3(Bipy). By improving device configuration with tris(8-hydroxyquinoline) aluminum(ALQ) as an electron transporting material, a maximum luminance of 800 cd/m 2 was obtained.
The research on electroluminescence based on europium(Ⅲ) complexes has come to an important phase. This article reviewed the progresses in photoluminescence and electroluminescence of Eu(Ⅲ) complexes in recent years from the views of the design of Eu(Ⅲ) com-plexes and optimization of device structures,and discussed some important factors influencing electroluminescence performance. The prob-lems existing in the practical application such as the volatility and thermal stability of Eu(Ⅲ) complexes in this area were discussed,and the possible corresponding solutions were briefly prospected.
