Ce^(3+)-冠醚配合物的紫外有机电致发光

Ultraviolet Organic Electroluminescence from Ce^(3+)-Crown Ether Complex

采用5d-4f跃迁的稀土Ce3+-冠醚配合物(Ce-二环己基并-18-冠-6,Ce-DC18C6)作为发光掺杂剂,4,4′-二(9-咔唑基)联苯(CBP)为基质,设计制备了紫外发光器件:ITO/CuPc/Ce-DC18C6∶CBP/Bu-PBD/LiF/Al,首次观测到峰位于376nm的Ce3+离子的紫外电致发光。通过对比器件的EL谱与Ce3+-冠醚配合物薄膜的PL谱发现,EL光谱中有部分来自Ce3+配合物中的Ce3+离子的。这种5d-4f电子跃迁的掺杂质量分数为3%时,该UV-发光器件的最大辐射功率为13μW/cm2。

Ultraviolet （UV） electroluminescence （EL） from organic light-emitting diode （OLED） with the emitter consisting of Ce^3＋-complex, Ce-dicyclohexano-18-crown-6 （Ce-DC18C6）, as dopant, and a holetransporting layer, 4,4＇-bis （9-carbazolyl） biphenyl （CBP） as the host have been investigated. The Ce^3＋- complex was prepared by reacting cerium chloride with dicyclohexano-18-crown-6 in a methanol. The EL devices with the structure of indium tin oxide （ITO）/copperphthalocyanine （CuPc）/Ce-DC18C6 ： CBP/2-（4-biphenylyl）-5-（4-tert-butylphenyl）-1 ,3,4-oxadiazole （Bu-PBD）/LiF/Al were employed to study the UV EL emission properties of the Ce^3＋ ion, and UV EL radiation peaked at about 376 nm from the Ce^3＋ ion was firstly observed. Comparing the EL with photoluminescent （PL） excitation and emission spectra, it is speculated that the UV EL emission was proved to be resulted from the 5d-4f transition of the Ce^3＋ ion in the Ce^3＋ -complex. And we have also found that the UV radiation with shorter wavelength is more valuable for using as excitation source of organic or inorganic phosphors, which will be expected to become solid state illumination with panel feature. A maximum radiance power of our UV-diodes is 13μW/cm^2 for 3% （mass fraction） Ce^3＋-complex doped CBP device.