A role of metal d-band in the interfacial electronic structure at organic/metal interface: PTCDA on Au, Ag and Cu
A role of metal d-band in the interfacial electronic structure at organic/metal interface: PTCDA on Au, Ag and Cu
复制标题
DOI：
10.1016/j.orgel.2008.05.017
复制
发表时间：
2008-10
影响因子：
3.2
通讯作者：
E. Kawabe;H. Yamane;R. Sumii;K. Koizumi;Y. Ouchi;K. Seki;K. Kanai
中科院分区：
文献类型：
--
作者：
E. Kawabe;H. Yamane;R. Sumii;K. Koizumi;Y. Ouchi;K. Seki;K. Kanai
我们分析了偶极子层在苝-3,4,9,10-四羧酸二酐（PTCDA）与贵金属（Au， Ag和Cu）界面处引起的真空能级位移（Δ）。紫外光电子能谱观测到的Δ的变化并没有表现出对金属功函数的简单依赖，这与Vázquez等人提出的界面态诱导密度（IDIS）模型的预测相矛盾。Vázquez， F. Flores， R. Oszwaldowski， J. Ortega， R. pacherez和A. Kahn, apple。冲浪。科学通报[j]。我们发现两个因素(1)PTCDA的最低未占据分子轨道（LUMO）与金属d带态之间的能量分离，由于轨道杂化而产生吸引效应；(2)吸附态与金属d带态之间的耦合矩阵元素，由于吸附态与金属d带态之间的轨道正交化而产生排斥效应，与Δ的形成有明显的相关性。我们的研究结果表明，PTCDA分子轨道和金属d带态之间的相互作用在决定界面电子结构方面起着重要作用，而这在IDIS模型的框架内没有考虑到。
We analyzed the vacuum level shift (Δ) induced by the dipole layer at the interfaces between perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) and noble metals (Au, Ag and Cu). The variation of Δ observed by ultraviolet photoelectron spectroscopy does not show a simple dependence on the metal work function, which contradicts the prediction by the induced density of interface states (IDIS) model proposed by Vázquez et al. [H. Vázquez, F. Flores, R. Oszwaldowski, J. Ortega, R. Pérez and A. Kahn, Appl. Surf. Sci 234 (2004) 107]. We found that two factors, (1) the energy separation between the lowest unoccupied molecular orbital (LUMO) of PTCDA and the metal d-band states, which results in the attractive effect due to the orbital hybridization, and (2) the coupling matrix element between the adsorbate states and the metal d-band states, which result in the repulsive effect due to the orbital orthogonalization between the adsorbate states and the metal d-band states, have a clear correlation with the Δ formation. Our results indicate that the interactions between the molecular orbitals of PTCDA and the metal d-band states play an important role in determining the interfacial electronic structure, which has not been taken into account within the framework of the IDIS model.