TU Darmstadt, Institut für Materialwissenschaft, Fachgebiet Materialmodellierung, Petersenstr. 32, D-64287 Darmstadt, Germany.
Chemphyschem. 2012 Jul 16;13(10):2443-54. doi: 10.1002/cphc.201200257. Epub 2012 Jun 22.
Size-dependent lattice expansion of nanoparticles is observed for many ionic compounds, including metal oxides, while lattice contraction prevails for pure metals. However, the physical origin of this effect, which is of importance for the thermodynamic, chemical and electronic properties of nanoparticles, is discussed controversially. After a survey of the experimental literature, revealing a wide variety of materials with size-dependent lattice expansion, we show that the negative surface stress is the key reason for lattice expansion, while the excess of lattice sums or point defects of various charge states can be excluded as general explanations. Ab initio calculations of surface stresses for various surface structures of metal oxides confirm the model of a surface-induced lattice expansion.
对于许多离子化合物，包括金属氧化物，纳米颗粒的晶格膨胀具有尺寸依赖性，而纯金属则表现出晶格收缩。然而，这种效应的物理起源对于纳米颗粒的热力学、化学和电子性质非常重要，其在学术界存在争议。在对实验文献进行调查后，我们发现了具有尺寸依赖性晶格膨胀的各种材料，表明负表面应力是晶格膨胀的关键原因，而晶格和的过剩或各种电荷态的点缺陷可以排除作为一般解释。金属氧化物各种表面结构的表面应力的从头计算证实了表面诱导晶格膨胀的模型。
