The electronic structure of tris(8-hydroquinoline) aluminum (Al q3) /rubrene/poly(ethylene glycol) dimethyl ether (PEGDE)/Al interfaces was studied using in situ ultraviolet photoelectron spectroscopy (UPS) and x-ray photoelectron spectroscopy (XPS). The UPS and XPS spectra allowed us to evaluate the complete energy level diagrams and to analyze the chemical interactions at the interfaces. When a PEGDE/rubrene double layer was inserted between Al and Al q3, the electron injection barrier height was greatly reduced compared to the interface without PEGDE/rubrene or with a single insertion layer of either PEGDE or rubrene.
Bibliographical noteFunding Information:
This work was supported by Institute of Physics and Applied Physics (IPAP) at Yonsei University, BK21 project of the Korea Research Foundation (KRF), and the KRF Grant funded by Korean Government (MOEHRD) (KRF-2005-015-C00130). Y. Yi thanks James E. Lyon for valuable discussions.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)