Multiplayer White Organic Light-Emitting Diodes with Different Order and Thickness of Emission Layers
XU Wei, LU Fu-han,CAO Jin,ZHU Wen-qing,JIANG Xue-yin*,ZHANG Zhi-lin,XU Shao-hong
Key Laboratory of Advanced Display and System Application, Ministry of Education, Shanghai University, Department of Materials Science, Shanghai University, Shanghai 200072, China
Abstract：In multilayer OLED devices, the order and thickness of the emission layers have great effect on their spectrum. Based on the three basic colours of red, blue and green, a series of white organic light-emitting diodes(WOLEDS)with the structure of ITO/CuPc(12 nm)/NPB(50 nm)/EML/LiF(1 nm)/Al(100 nm) and a variety of emission layer’s orders and thicknesses were fabricated. The blue emission material：2-t-butyl-9,10-di-(2-naphthyl)anthracene(TBADN) doped with p-bis(p-N, N-diphenyl-amono-styryl)benzene(DSA-Ph), the green emission material：tris-[8-hydroxyquinoline]aluminum(Alq3) doped with C545, and the red emission material：tris-[8-hydroxyquinoline]aluminum(Alq3) doped with 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) were used. By adjusting the order and thickness of each emission layer in the RBG structure, we got a white OLED with current efficiency of 5.60 cd·A-1 and Commission Internationale De L’Eclairage (CIE) coordinates of (0.34, 0.34) at 200 mA·cm-2. Its maximum luminance reached 20 700 cd·m-2 at current density of 400 mA·cm-2. The results were analyzed on the basis of the theory of excitons’ generation and diffusion. According to the theory, an equation was set up which relates EL spectra to the luminance efficiency, the thickness of each layer and the exciton diffusion length. In addition, in RBG structure with different thickness of red layer, the ratio of the spectral intensity of red to that of blue was calculated. It was found that the experimental results are in agreement with the theoretical values.
徐维,鲁富翰,曹进,朱文清,蒋雪茵*,张志林,许少鸿. 依发光层顺序和厚度调节的多发光层白色有机发光器件[J]. 光谱学与光谱分析, 2008, 28(02): 265-268.
XU Wei, LU Fu-han,CAO Jin,ZHU Wen-qing,JIANG Xue-yin*,ZHANG Zhi-lin,XU Shao-hong. Multiplayer White Organic Light-Emitting Diodes with Different Order and Thickness of Emission Layers . SPECTROSCOPY AND SPECTRAL ANALYSIS, 2008, 28(02): 265-268.
