Zn(BTZ)2白色有机电致发光材料的合成及其器件制备

以PCl₃为脱水剂,将邻氨基硫酚与水杨酸脱水环化合成出2-(2-羟基苯基)苯并噻唑,并进一步将所得产物与乙酸锌反应合成出2-(2-羟基苯基)苯并噻唑螯合锌(Zn(BTZ)₂)材料。以该配合物作为发光层制备出结构为ITO/PVK:TPD/Zn(BTZ)₂/Al近白色电致发光器件,其色坐标位于白场之内(x=0.242,y=0.359),在驱动电压为16V时,亮度达3200cdm²,对应的量子效率为0.32%。进一步在Zn(BTZ)₂中掺入橙红色染料Rubrene,制成ITO/PVK:TPD/Zn(BTZ)₂:Rubrene/Al结构器件,实现了纯白色发光(色坐标值:x=0.324,y=0.343),非常接近于白色等能点,且量子效率达0.47%。最后对上述器件的发光和电学性能进行了深入的研究和探讨。

Synthesis of Zn(BTZ)2 and Fabrication of White Organic Light-emitting Devices

Bis-2-(2-hydroxyphenyl)benzothiazolate)zinc (Zn(BTZ)₂) is one of the best white electroluminescent materials used in organic light emitting diodes (OLEDs). White light, which is composed of three discrete peaks in R/G/B regions, is very important and particularly useful for full color display. However, most of white OLEDs, so far, are fabricated with multilayer structures, which results in the complication of fabrication process and decline of quantum efficiency. So these devices are not suitable for the purpose of large scale industrial manufacture. In this paper, firstly, Zn(BTZ)₂ had been synthesized from the complex reaction between zinc acetate dihydrate and 2-(2-hydroxyphenyl) benzothiazolate. Then we used Zn(BTZ)₂ as main light emitting material and fabricated two types of organic white light emitting devices. The configurations of the devices are as follows: ITO/PVK: TPD/Zn(BTZ)₂/Al and ITO/PVK:TPD/Zn(BTZ)₂:Rubrene/Al. The bright and steady light emitting had been obtained, and the brightness of the devices came to 3200cd/m² and 2900cd/m² (at a driving voltage of 16V), respectively. We also measured the CIE coordinates of the above devices, they were (x=0.242, y=0.359) and (x=0.324, y=0.343), respectively. The latter CIE coordinate is very close to the equi energy point (x=0.33, y=0.33), and the corresponding quantum efficiency value is 0.47%. This value is higher than the former one, which is 0.32%. Details on the white light emitting characteristics of the devices were explained by the curves of current den sity voltage, optical current voltage and quantum efficiency current density, they were measured using a quantum efficiency measure system including the Keithley 485 Picoammeter and 2400 SourceMeter. We also discussed the emitting mechanisms of the material and the devices at last.