Novel starburst type amorphous materials N 1,N 1,N 4,N 1-tetra(biphenyl-4-yl)benzene-1,4-diamine, N 1,N 1,N 1,N 1-tetrakis(4-(thiophen-2- yl)phenyl)benzene-1,4-diamine, and N 1,N 1,N 1,N 1-tetrakis(4-(benzo[b]thiophen-2-yl)phenyl)benzene-1,4- diamine are synthesized and applied as hole injection layers (HILs) in organic light-emitting diodes (OLEDs). OLEDs containing these materials as a HIL demonstrated a significant reduction in the required driving voltage. We found that these molecules form a horizontally oriented amorphous thin film upon vacuum deposition. We observed a close correlation between the reduction of driving voltage in OLEDs and the orientation parameter of the organic thin films. We identified that the enhanced horizontal molecular orientation results in the lower driving voltage because of a decrease in the hole injection barrier at the anode/HIL interface.
|Number of pages||8|
|Journal||Journal of Physical Chemistry C|
|Publication status||Published - Apr 19 2012|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films