联苯乙烯类蓝色发光材料DPVBi的合成及发光性质研究

Synthesis and Luminescent Properties of Distyrylarylene Derivative Blue Emitting Material DPVBi

合成了联苯乙烯类蓝色有机发光材料DPVBi[4,4′ 二(2,2 二苯乙烯基) 1,1′ 联苯],用1H NMR,IR,元素分析等方法对其结构进行了表征。以DPVBi作发光层制备了电致发光器件,其结构为:ITO/CuPc/NPB/DPVBi/Alq3/LiF/Al,研究了器件的电致发光性质。器件最高亮度达4373cd/cm2,最大流明效率为1 24lm/W,在20mA/cm2电流密度驱动下的亮度为434cd/cm2,CIE色坐标为x=0 15,y=0 16,器件的蓝色发光具有较好的色纯度。重点对器件发光色度的稳定性进行了研究,结果表明,随电流密度(4～4000mA/cm2)的变化,器件色度具有很好的稳定性。

Organic electroluminescent (OEL) materials have recently attracted much interest due to their intriguing physical properties and potential applications to flat panel display. Blue EL emitter is essential for the development of a fullcolor display based either on the 'color changing medium' technology or the RGB filtered white emission. Many blue organic EL materials have been investigated by a number of researchers. Among them, the most promising ones are DSA derivatives. These classes of compounds generally offer many attractive properties such as high thermal stability and good film forming ability, etc.In this paper, the DSA derivative blue emitting material 4,4′bis(2, 2diphenylvinyl)1,1′biphenyl, i.e., DPVBi is synthesized via the WittigHorner reaction, and determined by IR, 1HNMR and elementary analysis. The photoluminescence(PL) of this compound in solid film and EL have been studied. DPVBi is intense blue fluorescent material and have a good film forming ability. The excitation and emission spectra of the vacuum deposited film of DPVBi have been studied. The emission spectrum shows the emission lies in the blue region with a peak at 460nm under the excitation of 360nm light.A blue organic light emitting diode(OLED) with the structure ITO/CuPc/NPB/DPVBi/Alq3/LiF/Al is studied. The EL spectrum of the device is similar to the PL spectrum of single layer DPVBi, indicating that the emission from the device resulted from the same excited state of the DSA derivative. The CIE chromaticity coordinates of the device are x=015, y=016, showing a very good blue purity. For the blue device, maximum luminance, the luminance under current density of 20mA/cm2 and luminous efficiency are 4 373cd/m2, 434cd/m2 and 124 lm/W, respectively. Particularly, it can be found that the CIE chromaticity coordinates of the device can keep better stability all the time with increasing current density as well as showing a very good blue purity. Because the stability of chromaticity is one of the most important factors to practical application of OLEDs, and DPVBi is a stable blue light emitter, it is suitable for applications to flat panel display.