We report the enhancement of hole current density in the hole transport part of an inverted top-emission organic light emitted diode by applying an organic insertion layer of 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN). Poor hole transporting performance of Al/4, 4′ -bis(N -phenyl-1-naphthylamino)biphenyl (NPB)/indium tin oxide is greatly improved by the HAT-CN insertion between Al and NPB layer. The highest occupied molecular orbital level onset of the NPB bends toward Fermi level at the HAT-CN/NPB interface. This extra charge generation layer made of pure organic molecules substantially enhances hole injection from Al anode as revealed by the results of ultraviolet photoelectron spectroscopy and J-V measurement data.
Bibliographical noteFunding Information:
This work is supported by Korea Research Council of Fundamental Science and Technology (KRCF) through the KRISS project of “Development of Advanced Industrial Metrology.”
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)