Phase-dependent electronic properties of monolayer and multilayer anthracene films on graphite [0001] surfaces
Phase-dependent electronic properties of monolayer and multilayer anthracene films on graphite [0001] surfaces
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DOI：
10.1103/physrevb.79.245410
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发表时间：
2009-06-01
影响因子：
3.7
通讯作者：
Friedlein, R.
中科院分区：
文献类型：
--
作者：
Bussolotti, F.;Han, S. W.;Friedlein, R.
用紫外光电子能谱研究了高取向热解石墨[0001]衬底上蒽薄膜的电子性质随温度的变化。随着衬底温度的升高，价线形状的变化已经明确地与不同分子取向和结构相（例如，“平放”单层和多层膜以及具有“直立”取向的多层相）。这些薄膜相的特征在于电离能变化高达0.9 eV的表面偶极子和可能在较小程度上极化能量的贡献被证明是有关的特定的分子包装/分子取向和分子-分子与分子-基板之间的相互作用。此外，对于单层系统，最高占据分子轨道（HOMO）的振动精细结构被清楚地揭示，从而允许详细研究HOMO空穴振动耦合和温度依赖性展宽。蒽薄膜显示了大量最近讨论的贡献的价线形状，出现作为“基准”系统，以研究在有机电子器件中的电荷传输相关的空穴的行为。
The evolution of the electronic properties of thin anthracene films on highly oriented pyrolytic graphite [0001] substrates as a function of temperature has been investigated using ultraviolet photoelectron spectroscopy. The change in the valence line shape with increasing substrate temperature has been univocally associated with the occurrence of different molecular orientations and structural phases (e.g., "flat-lying" mono- and multilayer films and a multilayer phase with a "standing-up" orientation). These thin-film phases are characterized by ionization energies varying up to 0.9 eV; the surface dipole and possibly to a minor extent polarization energy contributions are shown to be related to the specific molecular packing/molecular orientation and to the interplay between the molecule-molecule vs molecule-substrate interactions. Furthermore, for the monolayer system, a vibrational fine structure of the highest occupied molecular orbital (HOMO) is clearly revealed, thus allowing a detailed study of the HOMO hole-vibration coupling and the temperature-dependent broadening. Showing a large number of recently discussed contributions to the valence line shape, anthracene thin films emerge as "benchmark" systems to study the behavior of holes relevant for the charge transport in organic electronic devices.