Molecular Orientation and Electronic States of Vanadyl Phthalocyanine on Si(111) and Ag(111) Surfaces
Molecular Orientation and Electronic States of Vanadyl Phthalocyanine on Si(111) and Ag(111) Surfaces
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DOI：
10.1021/jp406906k
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发表时间：
2013-11-07
影响因子：
3.7
通讯作者：
Yokoyama, Toshihiko
中科院分区：
文献类型：
--
作者：
Eguchi, Keitaro;Takagi, Yasumasa;Yokoyama, Toshihiko
利用x射线光电子能谱、x射线吸收能谱和x射线磁圆二色性研究了非平面酞菁钒（VOPc）在Si(111)-（7 × 7）和Ag（111）表面的分子取向和电子结构。VOPc分子以与表面平行的方向吸附Ag(i11)，呈氧合构型。在界面处观察到VOPc的N和C原子与表面Ag原子之间的强相互作用，尽管没有观察到V原子的电子态发生明显变化，类似于多层VOPc的情况。另一方面，VOPc的0原子与表面Si原子的化学相互作用有利于氧降构型。这种化学相互作用导致V=O π键的断裂，并促进电子电荷转移到V- n - c分子轨道上。氧原子在V原子和Si表面之间的这种中介作用抑制了它们之间的直接相互作用，并且V的自旋磁矩保持与本体VOPc分子相同。
We have investigated the molecular orientation and electronic structures of nonplanar vanadyl phthalocyanine (VOPc) on the Si(111)-(7 x 7) and Ag(111) surfaces by X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and X-ray magnetic circular dichroism. The VOPc molecule adsorbs on Ag(I 11) in a parallel orientation to the surface with an oxygen-up configuration. A strong interaction between the N and C atoms of VOPc and surface Ag atoms is observed at the interface, although no marked change in the electronic state is observed for the V atom, similarly to the case for VOPc in a multilayer. On the other hand, the chemical interaction of the 0 atom of VOPc with the surface Si atoms favors the oxygen-down configuration. This chemical interaction causes the cleavage of the V=O pi bond and facilitates electron charge transfer to the V-N-C molecular orbitals. Such intermediation of the oxygen atom between the V atom and Si surface suppresses the direct interaction between them, and the spin magnetic moment of V remains the same as that of bulk VOPc molecules.