Energy level alignment regimes at hybrid organic–organic and inorganic–organic interfaces
2007 (English)In: Organic Electronics, ISSN 1566-1199, Vol. 8, no 1, 14-20 p.Article in journal (Refereed) Published
Ultraviolet photoelectron spectroscopy has been used to determine the energy level alignment at interfaces of molecular hole-transporting materials and various conductive substrates. Depending on the work function of the substrate, s, a transition between two different energy level alignment regimes has been observed: namely vacuum level alignment and Fermi level pinning. The transition is associated with spontaneous positive charge transfer across the interface to the organic semiconductors above a certain material-specific threshold value of s. The charge transfer results in formation of an interfacial dipole of a magnitude that scales with s. In the vacuum level alignment regime, the hole-injection barriers scale linearly with s, while in the Fermi level pinning regime, these barriers are constant and independent of s.
Place, publisher, year, edition, pages
2007. Vol. 8, no 1, 14-20 p.
Energy level alignment; OLED; Hole-transporting materials; Interfaces; Photoelectron spectroscopy; Hole-injection barrier
National CategoryEngineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-14582DOI: 10.1016/j.orgel.2006.10.006OAI: oai:DiVA.org:liu-14582DiVA: diva2:23943
Slawomir Braun, Wojciech Osikowicz, Ying Wang and William R. Salaneck, Energy level alignment regimes at hybrid organic–organic and inorganic–organic interfaces, 2007, Organic Electronics, (8), 1, 14-20.
Copyright: Elsevier Science B.V., Amsterdam.