摘要
采用碳酸锂(Li2CO3)为n型掺杂剂,苝四甲酸二酐(3,4,9,10 perylenetetracarboxylic dianhydride,PTC-DA)为母体材料,通过真空热蒸发方式制备了n型掺杂的PTCDA复合材料,将其作为电子注入材料应用到NPB/Alq3异质结有机电致发光器件中。研究发现,同Li2CO3∶BCP(1∶4)/Al结构和LiF/Al结构相比,Li2CO3∶PTCDA(1∶1)/Al结构能显著提高发光器件的亮度,器件功率效率也有所增加。发光器件性能的提高可以归因于两点:一是Li2CO3∶PTCDA(1∶1)的电导率显著高于Li2CO3∶BCP(1∶4)和本征Alq3,能够有效降低电流传导过程中的欧姆损失;二是阴极Al原子的渗透使Alq3/Li2CO3∶PTCDA界面变成欧姆接触。
Lithium carbonate doped 3,4,9,10-perylenetetracarboxylic dianhydride（Li2CO3∶PTCDA） was fabricated as electron injection layer in NPB/Alq3 heterojunction based organic light emitting diodes（OLEDs）.It was found that the current of OLED using Li2CO3∶PTCDA was strongly dependent on the Li2CO3 doping concentration.The OLED using Li2CO3∶PTCDA（1∶1） with Al as the cathode exhibits an improved power efficiency and significantly increased luminance,comparing with the one using Li2CO3∶BCP（1∶4） with Al as the cathode and the one using the regular LiF/Al cathode.It is because the electron conductivity for Li2CO3∶PTCDA/（1∶1） is much higher than that Li2CO3∶BCP（1∶4） and neat Alq3.In addition,it is found that there exist a Schottky barrier at the intrinsic interface of Alq3 and Li2CO3∶PTCDA（1∶1）,which suppress the electron transfer from Li2CO3∶PTCDA（1∶1） into Alq3.However,the release of Li atoms upon the Al deposition onto 1∶1 Li2CO3∶PTCDA could turn the interface into an ohmic contact,thereby delivering efficient electron injection from Li2CO3∶PTCDA（1∶1） into Alq3.We provided a class of high-function,low-cost,and easily fabricated n-doped material for the performance enhancement of OLEDs.
出处
《发光学报》
EI
CAS
CSCD
北大核心
2011年第4期387-392,共6页
Chinese Journal of Luminescence
基金
国家自然科学基金(50803014)资助项目
