Abstract Binding of functionalized organic molecules to oxide surfaces is an important step in the rational design of molecular devices. In the present investigation, we used synchrotron radiation photoelectron spectroscopy and near-edge X-ray absorption fine structure spectroscopy to determine the binding mode, electronic structure and adsorption geometry of phenylphosphonic acid (PPA) on TiO2(110)–(1 × 1). We found that PPA multilayers desorb below 380 K leaving a compact PPA monolayer adsorbed on the surface, which remains stable up to 780 K. In the 380–520 K temperature range, molecules are anchored to the surface via a single P–O–Ti covalent bond (monodentate configuration). Furthermore, the phenyl ring is tilted ~45° with respect to the surface plane and it either forms 45° or is randomly oriented with respect to [001] crystallographic direction. Raising the temperature above 520 K partially transforms the monodentate configuration to a mixed one- and twofold deprotonated bidentate binding mode, presumably after surface hydroxyl groups leave the surface as water molecules. This change in molecular binding does not alter the molecular electronic structure nor the adsorption geometry, which remain essentially unchanged.

中文翻译：

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苯基膦酸在金红石型TiO2(110)上的吸附

摘要 功能化有机分子与氧化物表面的结合是合理设计分子器件的重要步骤。在本研究中，我们使用同步辐射光电子能谱和近边 X 射线吸收精细结构光谱来确定苯基膦酸 (PPA) 在 TiO2(110)–(1 × 1) 上的结合模式、电子结构和吸附几何学. 我们发现 PPA 多层膜在 380 K 以下解吸，留下紧密的 PPA 单层吸附在表面上，在高达 780 K 时仍保持稳定。在 380-520 K 温度范围内，分子通过单个 P-O-Ti 锚定到表面共价键（单齿构型）。此外，苯环相对于表面平面倾斜~45°，它要么形成45°，要么相对于[001]结晶方向随机取向。将温度升高到 520 K 以上会部分地将单齿构型转变为混合的一倍和二倍去质子化双齿结合模式，大概是在表面羟基以水分子形式离开表面之后。分子结合的这种变化不会改变分子电子结构和吸附几何结构，它们基本上保持不变。