Influence of alkyl chain substitution on sexithienyl-metal interface morphology and energetics

被引:24
作者
Duhm, S.
Glowatzki, H.
Rabe, J. P.
Koch, N.
Johnson, R. L.
机构
[1] Humboldt Univ, Inst Phys, D-12489 Berlin, Germany
[2] Univ Hamburg, Inst Expt Phys, D-22761 Hamburg, Germany
关键词
D O I
10.1063/1.2204834
中图分类号
O59 [应用物理学];
学科分类号
摘要
The interface between Ag(111) and vacuum sublimated alpha,omega-dihexylsexithienyl (DH6T) was investigated using ultraviolet photoelectron spectroscopy and atomic force microscopy. While the monolayer of DH6T is lying flat on the metal surface, we found that already in the second molecular layer the molecules are almost standing upright. This abrupt change in molecular orientation lowered the hole injection barrier (Delta(h)) of DH6T/Ag by 0.5 eV between monolayer and multilayer. Delta(h) for DH6T multilayers was even lowered by 0.8 eV compared to unsubstituted sexithienyl multilayers. The reduction of Delta(h) is attributed to the electronic decoupling of molecules in the first from those in the second layer via the hexyl chains.
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页数:3
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