Efficient white organic light emitting devices with dual emitting layers

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• 作者：Yao-Shan Wu ; Shiao-Wen Hwang ; Hsian-Hung Chen ; Meng-Ting Lee ; Wen-Jian Shen and Chin H. Chen
• 关键词：Organic light emitting devices ; White ; Multi-layers
• 刊名：Thin Solid Films
• 出版年：2005
• 期刊代码：78_00406090
• 类别：ph
• 出版时间：2005
• 卷：488
• 期：1-2
• 页码：265-269
• 文件大小：174 K

摘要

In this paper, a new white organic light-emitting device (OLED) with the structure of indium tin oxide / CF_x / 1,4-bis[N-(1-naphthyl)-N′-phenylamino]-biphenyl (NPB) (30 nm)/NPB: 2,8-di(t-butyl)-5,11-di[4-(t-butyl)phenyl]-6,12-diphenylnaphthacene (20 nm; 1.6%) / 2-methyl-9,10-di(2-naphthyl) anthracene: p-bis(p-N,N-di-phenyl-aminostyryl)benzene (40 nm, 3%) / aluminum tris(8-hydroxyquinoline) (20 nm) / LiF (1 nm) / Al (200 nm) has been investigated. The device showed white emission with a high-luminous yield of 9.75 cd/A at 20 mA/cm², but its Commission Internationale de l'Eclairage chromaticity coordinates appeared to change from (0.34, 0.42) at 6 mA/cm2 to (0.27, 0.37) at 200 mA/cm² due to the shift of recombination zone. The change of color with drive current was suppressed by introduction of an electron-blocking layer of NPB along with a hole-blocking layer of aluminum (III) bis(2-methyl-8-quinolinato)4-phenylphenolato to the white OLED which successfully confined the recombination site and achieved a luminous yield of 9.9 cd/A at 20 mA/cm².