"Manipulation" of molecular orientation in ultrathin organic films: NTCDA on Ag(111)
"Manipulation" of molecular orientation in ultrathin organic films: NTCDA on Ag(111)
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超薄有机薄膜中分子取向的“操纵”：Ag(111) 上的 NTCDA
DOI：
10.1209/epl/i1998-00135-4
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发表时间：
1998
期刊：
影响因子：
1.8
通讯作者：
E. Umbach
中科院分区：
文献类型：
--
作者：
D. Gador;C. Buchberger;R. Fink;E. Umbach
用X射线光电子能谱（XPS）和近边X射线吸收精细结构谱（NEXAFS）研究了1，4，5，8-萘四甲酸二酐（NTCDA）在Ag（111）表面的成键及其分子取向。气相沉积的NTCDA膜显示出高取向秩序的单层和多层制度。在单层区域中，分子通过萘核的共轭π系统与基底强烈结合，这导致分子平面与Ag（111）基底平行取向。对于较厚的膜（例如，150 A）的分子取向强烈依赖于制备过程中的衬底温度。薄膜制备在285 K的结果在直立的分子，而低基板温度产生一个均匀的分子取向与平行于基板的分子平面。这种行为是由弱的分子间相互作用和吸附动力学解释。
The bonding of 1,4,5,8-naphthalene-tetracarboxylicacid-dianhydride (NTCDA) on Ag(111) and its molecular orientation were investigated by X-ray photoelectron (XPS) and near edge X-ray absorption fine-structure spectroscopy (NEXAFS). Vapour-deposited NTCDA films show high orientational order in the mono- and multi-layer regime. In the monolayer regime the molecules are strongly bound to the substrate via the conjugated π-system of the naphthalene core which leads to a parallel orientation of the molecular plane to the Ag(111) substrate. For thicker films (e.g., 150 A) the molecular orientation strongly depends on the substrate temperature during preparation. Film preparation at 285 K results in upright standing molecules, whereas low substrate temperatures yield a uniform molecular orientation with the molecular plane parallel to the substrate. This behaviour is explained by the weak intermolecular interaction and the adsorption kinetics.