Transcript Document

Studying OLED heterojunction in different parameters
Chen Xiaoqing, Sun Zhengyi, Ding Xunmin and Hou Xiaoyuan
Usually the current-voltage property of an OLED heterojunction is characterized by its threshold voltage and its
current at a specific voltage. However there is a problem in using “threshold voltage” that this value is different
under different scale. So I attempted to use two different parameters to characterize the curves.
I  A exp(B *V )
ln I  ln A  B *V
The head and tail are ignored (big problem). The intercept is A and the slope is B
An example which shows the advantage of these two parameters:
ITO/NPB(40nm)/Alq(80nm)/ LiF(differrent thicknesses) /Au(80nm)
As the LiF layer varies from 0nm to 6nm the threshold
voltage first turn lower then become higher and the gets lower.
The intercept (A) gets lower while the slope (B) goes higher.