School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China.
Phys Chem Chem Phys. 2018 Jun 13;20(23):15618-15625. doi: 10.1039/c8cp00744f.
Doping has been adopted as a versatile approach for tuning the adhesion of metal oxide/metal interfaces. Understanding the mechanism of doping at the interface adhesion on the atomic and electronic scale is crucial for the rational design and optimization of metal oxide/metal composites. In this work, we have investigated the effects of dopants on the adhesion of SnO2/Cu interfaces through first-principles calculations. Firstly, O-terminated a SnO2(110)/Cu(111) interface (denoted as I) was considered and the work of separation values of the interfaces with various dopants (Mo, Sb, Ti, Zn and Cu) were calculated to evaluate the interface adhesion strength. It was demonstrated that low-valence dopants (Zn2+ and Cu2+) enhance the adhesion strength of interface I, while high-valence dopants (Mo6+ and Sb5+) play the opposite role. Secondly, the strengthening effects of low-valence dopants were further verified in four candidate interfacial models with different atomic structures (denoted as II-V). The work of separation values indicated that the adhesion of all of the interfaces involved could be enhanced by low-valence doping. The electronic structure of the interface was demonstrated through density of states, charge density and charge density difference analyses. The results revealed that upon low-valence doping, the holes facilitate charge transfer between Cu and SnO2, which generates strong covalent bonds across the interface and thus significantly enhances the interface adhesion. This work not only provides insight into rational doping to enhance the adhesion of SnO2/Cu composites but can also be expanded upon for the design of other metal oxide/metal composites with strong interface adhesion.
掺杂已被采用为一种通用方法，用于调整金属氧化物/金属界面的附着力。理解掺杂在原子和电子尺度上对界面附着力的机制对于合理设计和优化金属氧化物/金属复合材料至关重要。在这项工作中，我们通过第一性原理计算研究了掺杂剂对 SnO2/Cu 界面附着力的影响。首先，考虑了 O 终止的 SnO2(110)/Cu(111)界面（表示为 I），并计算了具有各种掺杂剂（Mo、Sb、Ti、Zn 和 Cu）的界面的分离功值，以评估界面附着力强度。结果表明，低价掺杂剂（Zn2+和 Cu2+）增强了界面 I 的附着力，而高价掺杂剂（Mo6+和 Sb5+）则起到了相反的作用。其次，在具有不同原子结构的四个候选界面模型（表示为 II-V）中进一步验证了低价掺杂剂的增强效果。分离功值表明，所有涉及的界面的附着力都可以通过低价掺杂来增强。通过态密度、电荷密度和电荷密度差分析来研究界面的电子结构。结果表明，在低价掺杂下，空穴促进 Cu 和 SnO2 之间的电荷转移，在界面上产生强共价键，从而显著增强界面附着力。这项工作不仅为合理掺杂以增强 SnO2/Cu 复合材料的附着力提供了深入了解，还可以扩展到设计具有强界面附着力的其他金属氧化物/金属复合材料。
