Nanocomposite thin film based on ytterbium fluoride and N,N'-Bis(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine and its application in organic light emitting diodes as hole transport layer

作者：Duan Lian; Xie Jing; Zhang DeQiang; Wang LiDuo; Dong GuiFang; Qiao Juan; Qiu Yong^*

来源：Journal of Physical Chemistry C, 2008, 112(31): 11985-11990.

DOI：10.1021/jp8040555

We present a nanocomposite thin film. based on ytterbium fluoride (YbF3) and N,N'-bis(1-naphthyI)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine (NPB). The transmission electron microscopy study testified the presence of YbF3 nanoparticles with a size of 3-5nm, and these nanoparticles were observed to be uniformly dispersed in NPB. The conductance of YbF3 (50%)-doped NPB was measured to be 1.76 x 10(-5) S, much higher than the value of 5.81 x 10(-8) S for pure NPB film. However, unlike other p-doped systems, the absorption spectrum study shows that there is no obvious interaction between the host (NPB) and the dopant (YbF3). The hole mobility of YbF3 (50%)-doped NPB decreases to 7.31 X 10(-5) cm(2)/(Vs) at an electric field of 4 x 105 V/cm, while that of pure NPB film is 5.87 x 10(-4) cm(2)/(V S). We believe that the improved film conductivity and decreased hole mobility can enhance the built-in field and thus favor the electron injection. Due to the improved balance of holes and electrons, a double-layer device with YbF3-doped NPB as the HTL and tris(8-hydroxyquinolinoiato)aluminum (Alq(3)) as the electron transport and light-emitting layer shows a luminous efficiency of 4.50 cd/A at 300 mA/cm(2), 20% higher than that of control device with pure NPB as the HTL.

• 出版日期2008-8-7
• 单位清华大学