柔性衬底白色有机电致发光器件的制备及其性能

Fabrication and Study of Flexible Organic White-light-emitting Devices

采用以ITO为导电层的柔性透明PET基片作为衬底,以2(2羟基苯基)苯并噻唑螯合锌(Zn(BTZ)2)作为发光层制备出结构为PET/ITO/PVK∶TPD/Zn(BTZ)2/Al明亮的近白色柔性有机小分子电致发光器件。发光的色坐标值为x=0.242,y=0.359,在25V的直流电压驱动下,亮度为1000cd/m2,量子效率达到了0.30%。并进一步在Zn(BTZ)2中掺入橙红色染料Rubrene,制成PET/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=0.339,y=0.339),非常接近于白色等能点,驱动电压为25V时器件的亮度达1200cd/m2,且量子效率达0.35%。最后对器件的发光性能及机理进行了深入的研究和探讨。

Organic light emitting devices (OLED) has gained a rapid development recently. It is technically crucial in the field of plate panel displays in the future. The most important superiority of OLED is that it can realize flexible displays-flexible organic light emitting devices(FOLED). 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.Bis-2-(2-hydroxyphenyl)benzothiazolate zinc (Zn(BTZ)_2) is one of the best organic electroluminescent materials used for white light-emitting devices (OLED). PET slice with ITO is used as substrate of FOLED. We use Zn(BTZ)_2 as main light-emitting material and fabricate a new type of flexible organic white-light-emitting devices. The configurations of the devices are as follows:PET/ITO/PVK∶TPD/Zn(BTZ)_2/Al. The bright and steady light emitting has been obtained, and the brightness of the devices comes to 1 000 cd/m^2 (at a driving (voltage) of 25 V). We also measure the CIE coordinates of the above devices, which are (x = 0.242, y = (0.359)), and corresponding quantum efficiency value is 0.30%. Then the Rubrene is doped in Zn(BTZ)_2, and the configurations of this devices are as follows:PET/ITO/PVK∶TPD(/Zn(BTZ))_2/Al and ITO/PVK∶TPD /Zn(BTZ)_2∶Rubrene /Al. The brightness of the devices comes to 1 200 (cd/m^2) (at a driving voltage of 25 V), and the CIE coordinates of the above devices are (x = 0.339, y = (0.339)), and corresponding quantum efficiency value is 0.35%. Details on the white-light-emitting characteristics of the devices are explained by the diagram of current density-voltage, optical current-voltage and quantum efficiency-current density, which are measured using Keithley 485 Picoammeter and 2400 SourceMeter. Last, we also discuss the emitting mechanism of the material and the devices.