论文标题
在半导体COO（100）膜上的四苯基苯基卟啉的吸附，自组装和自动化
Adsorption, self-assembly and self-metalation of tetra-cyanophenyl porphyrins on semiconducting CoO(100) films
论文作者
论文摘要
自由碱（2H-TCNPP）在AU（111）上的薄膜上，在超高真空中研究了岩盐（RS）COO（100）上的薄膜（100），通过低度扫描式隧道式显微镜（STMSEDERISTION）在AU（111）上研究了自由碱的吸附特性（2H-TCNPP）在AU（111）上的吸附性能（100）。 （DFT）。 RS-COO（100）在AU（111）上的膜在合适的厚度范围内具有出色的质量。特别是，我们发现只有1 nm厚的膜显示出$ e_ \ mathrm {g} =（2.5 \ pm 0.2）\，\ textrm {ev} $的半导体能量差距。在300 k处沉积后，在长距离有序的上层建筑中，2H-TCNPP在80 k处稳定地覆盖和自组装。通过DFT分析了分子在表面和自组装中的吸附几何形状。我们发现，通过功能性氰基组通过氢桥键合稳定了自组件。我们的STS数据显示了COO的基本间隙内的分子状态。与计算出的DOS相比，我们确定了边界轨道的能量位置，发现前三个Lumo状态2H-TCNPP位于带隙内，而HOMO则位于COO传导带边缘以下1 eV。退火至420 K后，分子在STM图像中改变了外观，并形成了位于分子中心的新的突出电子状态。我们将这种更改的配置解释为通过氧化物表面上的自动化产生的共同-TCNPP。
The adsorption properties of free base 5,10,15,20-tetrakis(p-cyanophenyl)porphyrin (2H-TCNPP) on thin films of rock salt (rs) CoO(100) on Au(111) was studied in ultra-high vacuum by a combination of low-temperature scanning tunneling microscopy and spectroscopy (STM/STS) and density functional theory (DFT). Films of rs-CoO(100) on Au(111) are prepared with excellent quality in a suitable thickness range. Particularly, we found that films of only 1 nm thickness show a semiconducting energy gap of $E_\mathrm{g}=(2.5\pm 0.2)\,\textrm{eV}$. Upon deposition at 300 K, 2H-TCNPP adsorbs flat-lying and self-assembles in a long-range ordered superstructure that is stable at 80 K. The adsorption geometry of the molecules on the surface and within the self-assembly is analyzed by DFT. We find that the self-assemblies are stabilized by hydrogen bridge bonding via the functional cyano groups. Our STS data shows molecular states within the fundamental gap of the CoO. By comparison with the calculated DOS we determine the energetic positions of the frontier orbitals and find that the first three LUMO states 2H-TCNPP are located within the band gap, whereas the HOMO is shifted 1 eV below the CoO conduction band edge. Upon annealing to 420 K the molecules change their appearance in STM images and a new prominent electronic state located at the center of the molecule is formed. We interpret this changed configuration as Co-TCNPP created by self-metalation on the oxide surface.
