对固-液界面的构造、组成和性能的原子性认识，是我们理解许多技能设备（如化学传感器、电池或燃料电池）中材料的稳定性或性能的关键。常日，此类详细信息只能从原子仿照或理论与实验的结合（如对光谱丈量的阐明）才能得到。
考虑到液体环境的存在，由于身分空间和构象空间很大，特殊是对付电化学的固-液界面，界面仿照受到很大的寻衅，个中界面身分的稳定性也受电解质长程空间-荷电层的能量影响，这个影响范围是纯原子界面模型常日所无法达到的远程范围。将密度泛函理论耦合到隐式溶剂化模型可以成功地仿照与溶剂化干系的效应。在这些情形下，显式的电解质溶液（例如，带离子的水）被溶剂的均匀场描述所代替，打算本钱大大降落。但对付多组分半导体-水界面，其表面-水相互浸染更为强烈、更为常见。而溶剂化壳会带来诸多问题，因而隐式溶剂化模型是否涌现偏差急需明确。
该研究测试了一些标准方法以利用隐式溶剂化模型精确仿照半导体的能带对准，并以显式仿照为难刁难照对以下水中半导体进行了模型的验证：具有分子吸附水的金红石r-TiO2和CdS、具有解离吸附水的GaN和同时具有这两种情形的锐钛矿α-TiO2、GaAs和GaP。来自瑞士洛桑联邦理工学院材料理论和仿照（THEOS）和国家材料打算设计与创造中央（MARVEL）的Nicolas G.Hörmann领导的团队创造，如果利用第一层水分子作显式仿照，即可用自洽连续介质（SCCS）隐式水模型在不同材料和界面端以0.1-0.2 V的精度确定半导体-水界面处静电势的绝对校准。另一方面，不包含显式水的仿照很可能具有1 V或更高的带对准偏差。先前创造所有上述半导体端点均为稳定或亚稳定状态，但作者指出，为了在隐式模型中准确地捕获界面势低落，必须明确地描述第一个溶剂化壳层。此外，他们创造，因隐式模型中不存在显式水表面，隐式模型主体中的静电势比SCCS溶剂化的真空度降落约0.33 eV。该研究结果为在隐式环境中电化学固液界面的精确仿照供应了辅导，并对界面水层的浸染和性子以及界面水层可以被连续介质模型描述的程度有了新的认识。
该文近期揭橥于npj Computational Materials 5: 100 (2019)，英文标题与择要如下，点击https://www.nature.com/articles/s41524-019-0238-4可以自由获取论文PDF。
Absolute band alignment at semiconductor-water interfaces using explicit and implicit descriptions for liquid water
Nicolas G. Hörmann, Zhendong Guo, Francesco Ambrosio, Oliviero Andreussi, Alfredo Pasquarello & Nicola Marzari
Quantum mechanical simulations that include the effects of the liquid environment are highly relevant for the characterization of solid-liquid interfaces, which is crucial for the design of a wide range of devices. In this work we present a rigorous and systematic study of the band alignment of semiconductors in aqueous solutions by contrasting a range of hybrid explicit/implicit models against explicit atomistic simulations based on density-functional theory. We find that consistent results are obtained provided that the first solvation shell is treated explicitly. Interestingly, the first molecular layer of explicit water is only relevant for the pristine surfaces without dissociatively adsorbed water, hinting at the importance of saturating the surface with quantum mechanical bonds. By referencing the averaged electrostatic potentials of explicit and implicit water against vacuum, we provide absolute alignments, finding maximal differences of only ∼ 0.1–0.2 V. Furthermore, the implicit reference potential is shown to exhibit an intrinsic offset of −0.33 V with respect to vacuum, which is traced back to the absence of an explicit water surface in the implicit model. These results pave the way for accurate simulations of solid-liquid interfaces using minimalistic explicit/implicit models.
