摘要
有机电致发光器件(OLEDs)在使用过程中,易受到空气中水汽、氧气及其它污染物的影响从而导致其工作寿命降低。本文将具有良好光透过率和热稳定性的MgF2薄膜与在水汽和氧气中具有良好稳定性的Se薄膜通过真空蒸镀制成复合薄膜作为OLEDs的封装层,以达到提高器件使用寿命的目的。器件各功能层蒸镀完成后,保持真空度(3×10-4 Pa)不变,在阴极表面蒸镀MgF2/Se薄膜封装层。比较了绿光OLED器件(器件结构为ITO/CuPc/NPB/Alq3:C-545T/Alq3/LiF/Al)封装前后的亮度-电压-电流密度特性、电致发光光谱及寿命。研究发现,经过MgF2/Se封装后,器件的电流密度-电压特性、亮度和发光光谱几乎没有受到影响,二者的光谱峰都在528nm处,色坐标(CIE)分别为(0.355 5,0.613 1)和(0.356 0,0.610 4),只是起亮电压由3V变为4V;器件的寿命由原来的175h变为300h,提高了1.7倍。因此,MgF2/Se薄膜是一种有效的OLEDs无机薄膜封装层。
Organic light emitting devices （OLEDs） are easy to be influenced by water vapor,oxygen of air and other pollutants,which leads to the reducing of their working life. In the paper, the MgF2 thin film with a good optical transmission and thermal stability and the Se thin film with a good stability in water vapor and oxygen were made in to composite thin film by vacuum evaporation as OLED encapsulation layer,and the lifetime of the device would be improved in expectation. The MgF2/Se thin film was vaporized on the cathode surface in the same conditon of vacuum （3× 10-4 Pa） after the deposition of functional layers in OLEDs was completed. The luminance-voltage-current densities and electroluminesce spectra of green OLEDs （the device structure is ITO/CuPc/NPB/Alq3 ：C-545T/Alq3/LiF/A1. ）before and after encapsulation are compared. The research shows that the current density-voltage and electroluminesce spectrum of OLEDs are scarcely influenced by MgF2/Se encapsulation layer and both of their spectra are at 528 nm,the color coordinates are （0. 355 5,0. 613 1） and （0. 356 0,0. 610 4） ,respectively, and the turn-on voltage is only changed from 3 V to 4 V. However, the lifetime of the device with MgF2/Se thin film is increased from 175 h to 300 h,about 1.7 times of the original. So the MgF2/Se thin film is an effective inorganic thin film encapsulation layer for OLEDs.
出处
《光电子．激光》
EI
CAS
CSCD
北大核心
2013年第3期535-538,共4页
Journal of Optoelectronics·Laser
基金
陕西省专利产业化(2005ZZ-04)
陕西省教育厅产业化(06JC23)资助项目
关键词
MGF2
SE
薄膜封装
寿命
MgF2/Se
thin film encapsulatiom lifetime
