Electric fields induced by energy level pinning at organic heterojunctions.

Authors :: Wilke, A.
Amsalem, P.
Frisch, J.
Bröker, B.
Vollmer, A.
Koch, N.
Source :: Applied Physics Letters; 3/21/2011, Vol. 98 Issue 12, p123304, 3p, 2 Diagrams
Publication Year :: 2011
Abstract: We investigated the energy levels at organic heterojunctions comprising the donor diindenoperylene (DIP) on top of the acceptor C<subscript>60</subscript> with photoelectron spectroscopy. The intermolecular interaction is weak as evidenced on a moderate work function electrode by a small interface dipole of 0.15 eV and flat energy levels on both sides of the junction. When a high work function electrode is used, the DIP levels become Fermi-level pinned and an electric field drops within the C<subscript>60</subscript> layer underneath. The electric field distribution within an organic opto-electronic device may thus be adjusted by employing interfacial energy level pinning, even at physisorptive organic/organic interfaces. [ABSTRACT FROM AUTHOR]