High Hole-Mobility Molecular Layer Made from Strong Electron Acceptor Molecules with Metal Adatoms
High Hole-Mobility Molecular Layer Made from Strong Electron Acceptor Molecules with Metal Adatoms
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DOI：
10.1021/acs.jpclett.7b02390
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发表时间：
2017-11-02
影响因子：
5.7
通讯作者：
Kosugi, Nobuhiro
中科院分区：
文献类型：
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作者：
Yamane, Hiroyuki;Kosugi, Nobuhiro
通过同步辐射角分辨光电子能谱 (ARPES) 研究了 Au(111) 上 7,7,8,8-四氰基醌二甲烷 (TCNQ) 和 2,3,5,6-四氟-TCNQ(F(4)TCNQ) 单层的电子结构。与物理吸附的 TCNQ/Au(111) 界面相比，F(4)TCNQ/Au(111) 界面处的高分辨率核心级光发射光谱和低能电子衍射显示了从 Au 到 F(4)TCNQ 的强电荷转移 (CT) 以及 Au 原子从下面的 Au(111) 表面偏析的证据，这表明二维自发形成的可能起源F(4)TCNQ-Au网络。 ARPES实验揭示了由于吸附原子介导的分子间相互作用，在CT诱导的F(4)TCNQ-Au网络的最高价态中具有低空穴注入势垒和大能带色散，带宽为260 meV。这些结果表明，具有金属吸附原子的强电子受体分子可以通过控制分子-金属有序结构及其CT相互作用来形成高空穴迁移率分子层。
The electronic structure of 7,7,8,8-tetracyanoquinodimethane (TCNQ) and 2,3,5,6-tetrafluoro-TCNQ(F(4)TCNQ) monolayers on Au(111) has been investigated by means of angle-resolved photoemission spectroscopy (ARPES) with synchrotron radiation. In contrast to the physisorbed TCNQ/Au(111) interface, the high-resolution core-level photoemission spectra and the low-energy electron diffraction at the F(4)TCNQ/Au(111) interface show evidence for the strong charge transfer (CT) from Au to F(4)TCNQ and for the Au atom segregation from the underlying Au(111) surface, suggesting a possible origin of the spontaneous formation of the two-dimensional F(4)TCNQ-Au network. The ARPES experiment reveals a low hole-injection barrier and large band dispersion in the CT-induced topmost valence level of the F(4)TCNQ-Au network with 260 meV bandwidth due to the adatom-mediated intermolecular interaction. These results indicate that strong electron acceptor molecules with metal adatoms can form high hole-mobility molecular layers by controlling the molecule-metal ordered structure and their CT interaction.