Work-Function Modification beyond Pinning: When Do Molecular Dipoles Count?
Work-Function Modification beyond Pinning: When Do Molecular Dipoles Count?
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DOI：
10.1021/nl101874k
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发表时间：
2010-11-01
期刊：
影响因子：
10.8
通讯作者：
Zojer, Egbert
中科院分区：
文献类型：
--
作者：
Hofmann, Oliver T.;Egger, David A.;Zojer, Egbert
在许多情况下，在金属表面上沉积强电子供体或受体的单层导致作为费米能级钉扎的结果的与金属无关的功函数。这就提出了一个问题，在这种情况下，分子偶极子，也经常被用来调整界面能量，是否仍然可以有任何影响。我们使用密度泛函理论表明，偶极的空间位置是决定因素，并且只有直接金属分子界面之外的偶极才允许功函数变化超出钉扎极限。
Deposition of monolayers of strong electron donors or acceptors on metal surfaces in many cases results in a metal-independent work function as a consequence of Fermi-level pinning. This raises the question whether in such a situation molecular dipoles, which are also frequently used to tune the interface energetics, still can have any impact. We use density functional theory to show that the spatial position of the dipoles is the determining factor and that only dipoles outside the immediate metal molecule interface allow work-function changes beyond the pinning limit.