Department of Chemistry, The University of Arizona, 1306 E. University Blvd., Tucson, Arizona 85721, USA.
J Chem Phys. 2011 Sep 28;135(12):124702. doi: 10.1063/1.3637051.
The image state manifold of the dipolar organic semiconductor vanadyl naphthalocyanine (VONc) on highly oriented pyrolytic graphite is investigated by angle-resolved two-photon photoemission (AR-TPPE) spectroscopy in the 0-1 monolayer regimes. Interfacial charge-transfer from the image potential state of clean graphite populates a near-resonant VONc anion level, identifiable by the graphite image potential state by its distinct momentum dispersion obtained from AR-TPPE. This affinity level is subject to depolarization by the neighboring molecules, resulting in stabilization of this state with coverage. Near a coverage of one monolayer, a hybrid image potential/anion state is also formed, showing progressive localization with coverage. Intensities for all these features develop rather differently with molecular coverage, pointing towards the different types of charge-transfer interactions at play at this interface.
通过在 0-1 单层范围内进行角度分辨双光子光发射 (AR-TPPE) 光谱学研究，研究了二聚有机半导体钒萘酞菁 (VONc) 在高取向热解石墨上的图像状态流形。通过 AR-TPPE 获得的独特动量色散，可以从石墨像电荷状态来识别来自清洁石墨像电荷状态的界面电荷转移，将其填充到近共振的 VONc 阴离子能级中。该亲和能级受到相邻分子的去极化作用，从而随着覆盖度的增加而稳定该能级。在接近单层覆盖度时，也形成了混合的像电荷/阴离子态，并且随着覆盖度的增加，其显示出逐渐的局域化。所有这些特征的强度随分子覆盖度的变化而有很大的不同，这表明在该界面上存在不同类型的电荷转移相互作用。
