利用级联式能量传递的有机电致发光器件

为了提高掺杂型有机电致发光器件(OLED)中主体发光材料与客体荧光染料间能量传递的效率,2-对联苯-8-羟基喹啉锌(Zn ₂)作为NPB : DCJTB掺杂体系的能量助传递剂,制备了结构如:ITO/NPB/NPB : DCJTB/Zn ₂/BCP/Al的有机电致发光器件。助传递剂Zn ₂的加入,能够两次利用Frster能量转移,实现NPB向DCJTB级联式的能量传递过程,提高低浓度时掺杂染料DCJTB红光发射的纯度;此外,还探讨了三者间能量传递的有效距离,即当助传递剂与掺杂体系的距离在小于10 nm的范围内,其参与能量传递的效率随着距离的增加而逐渐下降。

Organic Light-emitting Diodes Using Cascade Energy Transfer Process

In order to increase the energy transfer from host to guest in doping organic light-emitting diodes (OLEDs), bis(2-biphenyl-4'-yl-8-quinolinolato)zinc Zn 2 was synthesized and used to assist the energy transfer from N,N'-bis-(3-naphthyl)-N,N'-biphenyl-(1,1'-biphenyl)-4,4'-diamine (NPB) to red fluorescent dye 4-(dicyanomethylene)-2-t-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB). OLED with the structure of ITO/NPB/NPB:DCJTB/Zn 2/BCP/Al were fabricated. Without the Zn 2 layer, incomplete energy transfer from NPB to DCJTB led to both emission from host and guest. After Zn 2 was added in to the device, only red emission of DCJTB material was detected in electroluminescence spectra. The efficient emission of DCJTB is achieved via energy transfer with a cascade process from NPB to Zn 2 and then to DCJTB, which results in a complete energy transfer from host to guest. In particular, as the concentration of DCJTB is only 0.5%, red-light-emitting OLED is successfully fabricated using Frster transfer theory at twice. Traditionally, the fabrication of OLED using the assistance material needs thermal evaporation with three sources. However the red OLED only needs two sources, which is very useful in application in the future. In addition, by varying the distance between Zn 2 and the doping system, the efficiency of energy transfer is changed. When the distance is below 10 nm, Zn 2 has an influence on the energy transfer of the doping system. And the longer the distance is, the lower the efficiency is.