混合蓝色和绿色发射的高亮度白色有机电致发光器件

使用星形六苯芴类新材料1,2,3,4,5,6-hexakis(9,9-diethyl-9H-fluoren-2-yl)benzene (HKEthFLYPh)分别制备了三种不同结构的有机电致发光器件. 在结构为indium-tin oxide (ITO)/NPB (40 nm)/HKEthFLYPh (10 nm)/Alq3(50 nm)/Mg:Ag (200 nm)的器件中, 获得了两个电致发光谱峰分别位于435 和530 nm处的明亮白光. HKEth-FLYPh是能量传输层; N,N’-bis-(1-naphthyl)-N,N’-diphenyl-(1,1’-biphenyl)-4,4’-diamine (NPB)是空穴传输层和蓝色发光层; tris(8-hydroxyquinoline)aluminum (Alq3)是电子传输层和绿色发光层. 结果表明, 当驱动电压为15 V时, 器件的最大亮度达到8523 cd·m-2; 在5.5 V时, 器件达到最大流明效率为1.0 lm·W-1. 在电压为9 V时, CIE色坐标为(0.29, 0.34). 此外, 通过改变HKEthFLYPh层的厚度, 发现蓝色发射的相对强度随着HKEthFLYPh层厚度的增加而增强.

Bright White Organic Light-Emitting Diode Mixed Blue and Green Emission

Double-layer and triple-layer organic light-emitting diodes (OLEDs) were fabricated using a novel star-shaped hexafluorenylbenzene organic material, 1,2,3,4,5,6-hexakis(9,9-diethyl-9H-fluoren-2-yl)benzene (HKEthFLYPh) as an energy transfer layer, N,N’-bis-(1-naphthyl)-N,N’-diphenyl-(1,1’-biphenyl)-4,4’-diamine (NPB) as a hole-transport layer (HTL) and blue emissive layer (EML), and tris (8-hydroxyquinoline)aluminum (Alq3) as an electron-transport layer (ETL) and green light-emitting layer. Bright white light was obtained with a triple-layer device structure of indium-tin-oxide (ITO)/NPB (40 nm)/HKEthFLYPh (10 nm)/Alq3 (50 nm)/Mg:Ag (200 nm). A maximum luminance of 8523 cd·m-2 at 15 V and a power efficiency of 1.0 lm·W-1 at 5.5 V were achieved. The Commissions Internationale de L’Eclairage (CIE) coordinates of the device were (0.29, 0.34) at 9 V, which located in white light region. With increasing filmthickness of HKEthFLYPh, light emission intensity fromNPB increased compared to that of Alq3.