[15p-2N-1~17] 12.2 Characterization and Materials Physics

[15p-2N-12] Complex energy-level alignment at donor/acceptor interfaces

〇Kouki Akaike^1,2, Georg Heimel², Martin Oehzelt^2,3, Norbert Koch^2,3 (1.Tokyo Univ. of Sci., 2.Humboldt Univ., 3.Helmholtz-Zentrum Berlin)

Keywords:donor/acceptor interface,interface disorder,photoelectron spectroscopy

Employing photoelectron spectroscopy and complementary electrostatic simulations, we revealed that the up-down vacuum level (VL) shift, which widely has been observed at phthalocyanine/fullerene interfaces, is attributed to the increase in the disorder of the outermost phthalocyanine layer upon interface formation. The interface disorder broadens the HOMO of the layer and pins the tail states to the Fermi level. As a result, the electron transfer occurs and resulting potential produces the complex VL shift. We will also report the study on another donor/acceptor interface where the ‘reversed’ VL shift was measured.