The electronic structures of Ag-doped In 2 O 3 (IAgO) and its energy level alignments with a N,N'-bis-(1-naphthyl)-N,N'-diphenyl-1,1′-biphenyl-4,4′-diamine (NPB) hole transport layer (HTL) were investigated using in situ ultraviolet and X-ray photoelectron spectroscopies (UPS and XPS). As compared to the conventional Sn-doped In 2 O 3 (ITO), IAgO has less oxygen vacancies leading to a higher work function (WF). The lower hole injection barrier (Φ h ) from IAgO to a NPB HTL is observed, which is attributed mainly to its higher WF and interface dipoles. The UPS measurements reveal that the Φ h is 0.87 eV at NPB/IAgO while 1.11 eV is at NPB/ITO. Therefore, IAgO could be an alternative transparent anode in organic optoelectronics.
Bibliographical noteFunding Information:
This work was supported by a research project of the National Research Foundation of Korea (2015R1C1A1A01055026, 2012M3A7B4049801) and Yonsei University Future-Leading Research Initiative of 2014 (2015-22-0123).
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Physics and Astronomy(all)
- Surfaces and Interfaces
- Surfaces, Coatings and Films