AVS 59th Annual International Symposium and Exhibition
    Oxide Heterostructures-Interface Form & Function Focus Topic Monday Sessions
       Session OX+SS+TF+MI-MoA

Invited Paper OX+SS+TF+MI-MoA7
Energy-Level Alignment at Organic/Oxide Interfaces

Monday, October 29, 2012, 4:00 pm, Room 007

Session: Chemistry of Oxide Surfaces and Interfaces
Presenter: Z.-H. Lu, University of Toronto, Canada
Authors: M.T. Greiner, University of Toronto, Canada
Z.-H. Lu, University of Toronto, Canada
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Oxide/organic interfaces play an important role in many organic electronic device designs. Oxides are frequently used as buffer layers to tune the energy-level alignment between electrodes and organic semiconducting layers, and thus allow for efficient hole/electron injection. As per the 'integer charge-transfer' (ICT) model, energy-level alignment at electrode/organic interfaces is governed by the electrode's Fermi level and the organic molecule's oxidation/reduction potential. While the ICT model was originally proposed for organic/organic interfaces, it also applies to a broad range of transition metal oxides. In this presentation we will discuss the energy-level alignment (ELA) of several organic semiconductors with transition-metal oxides. We will show that ELA is primarily governed by an oxide's work function, and that ELA is relatively insensitive to oxide electronic structure. As transition metal oxides can exhibit a wide range of work functions (~ 2 - 7 eV), and can possess a wide range of electronic properties (p-type to n-type) they are very versatile materials for use in organic electronics. We will their properties—such as work function and electronic structure—can best be utilized for use as buffer layers in organic light-emitting diodes and organic photovoltaics.