Substrate-mediated band-dispersion of adsorbate molecular states
Substrate-mediated band-dispersion of adsorbate molecular states
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DOI：
10.1038/ncomms2522
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发表时间：
2013-02
影响因子：
16.6
通讯作者：
M. Wiessner;J. Ziroff;F. Forster;M. Arita;K. Shimada;P. Puschnig;A. Schöll;F. Reinert
中科院分区：
文献类型：
--
作者：
M. Wiessner;J. Ziroff;F. Forster;M. Arita;K. Shimada;P. Puschnig;A. Schöll;F. Reinert
分子凝聚体中的载流子迁移率通常很小，因为在传统半导体中非常有效的相干输运受到无序和小分子间耦合的阻碍。通常只有在特殊情况下才能观察到显著的带散，例如在有机单晶中芳香分子的π堆积。基于角分辨光电子能谱，我们以平面π共轭分子为例，证明了与金属衬底的杂化可以显著增加分子沿表面选择性方向的离域化。在从头计算的支持下，我们展示了这种机制是如何耦合有机层中的单个分子，从而导致面内电荷载流子迁移率的增强。
Charge carrier mobilities in molecular condensates are usually small, as the coherent transport, which is highly effective in conventional semiconductors, is impeded by disorder and the small intermolecular coupling. A significant band dispersion can usually only be observed in exceptional cases such as for π-stacking of aromatic molecules in organic single crystals. Here based on angular resolved photoemission, we demonstrate on the example of planar π-conjugated molecules that the hybridization with a metal substrate can substantially increase the delocalization of the molecular states in selective directions along the surface. Supported byab initiocalculations we show how this mechanism couples the individual molecules within the organic layer resulting in an enhancement of the in-plane charge carrier mobility.