摘要
研究了PVK∶DCJTB体系的发光特性。实验结果表明,PVK∶DCJTB薄膜光激发时,PVK和DCJTB之间存在能量传递,DCJTB的浓度从1%增加到2%,能量传递效率明显增强,但仍然不充分。引入Alq3层后的PVK∶DCJTB/Alq3双层薄膜,PVK的发光被有效地抑制了,Alq3明显促进了PVK向DCJTB的能量传递效率,说明Alq3起到了能量传递的"桥梁"作用。而结构为ITO/PVK∶DCJTB/Alq3/LiF(1nm)/Al的器件的电致发光光谱与光致发光光谱明显不同。电致发光时,Alq3层的发光的相对强度比光致发光时大许多,而且发光强度随着驱动电压的增加而增强,说明随电压的增加,有更多的空穴注入到Alq3层,致使载流子在Alq3层的复合几率随电场的增强而增大。
It is effective method to enhance brightness and to change emission color by doping fluorescent dye in active layer of organic light-emitting diodes （OLEDs）. The energy transfer in the blend films is significant information of the devices to understand the excited state process. In this paper, the luminescence properties of the PVK： DCJTB blend film was studied. The results show that the efficiency of energy transfer from PVK to DCJTB is increased as the concentration of DCJTB changed from 1% to 2%, but it is not complete yet. The emission of PVK was obviously reduced by the introduction of Alq3 layer to form double-layer film PVK： DCJTB/Alq3. The layer of Alq3 plays a energy transfer ＂bridge＂ role in the double-layer film. It is obviously different between EL and PL spectra of the device with the structure of ITO/PVK： DCJTB/Alq3/LiF/Al. The emission of Alq3 is relative strong in EL than that in PL, and the intensity of Alq3 emission is enhanced with the increase of drive voltage. It is because that the recombination probability of electrons and holes is increased in the Alq3 layer by increase of the number of injected holes as the increase of electric field in the device. The result of this paper is meaningful for the understanding of energy transfer in the blend films as well as the recombination zone in the double-layer devices.
出处
《发光学报》
EI
CAS
CSCD
北大核心
2008年第6期957-961,共5页
Chinese Journal of Luminescence
基金
国家重点基础研究发展计划(2003CB314707)
国家自然科学基金(10434030
90401006)
北京交通大学博士生创新基金(48023)资助项目
关键词
能量传递
有机电致发光
光致发光
掺杂
energy transfer
organic electroluminescence
photoluminescence
doping
