摘要
建立了双层有机发光二极管中载流子在有机层界面复合的无序跳跃理论模型 .由于有机分子材料的空间及能带结构的无序性 ,采用刚体模型处理有机层界面问题是不恰当的 ,而采用无序跳跃模型比较合理 .复合效率及复合电流由载流子跳跃距离、有机层界面的有效势垒高度及该界面处的电场强度分布所决定 :在双层器件ITO α NPD Alq3 Al中 ,当所加电压小于 19 5V时 ,复合效率随着载流子跳跃距离的增加而增加 ,而大于 19 5V时 ,复合效率随着其距离的增加而减少 ;复合效率随着有机层界面有效势垒高度的增加而增加 ;有机层界面电场强度突变程度增大时 ,复合效率增大 ,但当界面两侧电场强度差值达到 2 4× 10 5V cm时 ,复合效率反而减少 .此理论模型与实验结果比较符合 .
A disorder hopping model for carriers recombination at organic/organic interface (OOI) in double-layer organic light emitting diodes (OLEDs) was presented. According to the structure of an OOI as well as spatial and energetic disorder of hopping states, it was more reasonable to use the disorder hopping model than to use the Fowler-Nordheim formalism. It was shown that the carriers hopping distance, the effective barrier height and the electric field contribution had heavy effects on recombination efficiency. Firstly, when the applied voltage was less than 19 5V (in double-layer OLEDs ITO/α-NPD/Alq 3/Al), recombination efficiency increased with the increase of hopping distance, while the applied voltage was larger than 19 5V, it decreased with the increase of hopping distance; secondly, it also increased with the increase of effective barrier height at OOI; Finally, it increased with the increase of differences of electric field at OOI, while it decreased when the value of differences of electric field reached 24×10 5V/cm. These results were consistent with some experiments.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2004年第1期286-290,共5页
Acta Physica Sinica
基金
湖南省自然科学基金 (批准号 :98JJY2 0 47)资助的课题~~
