Japan Advanced Institute of Science and Technology, School of Materials Science, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan.
Adv Colloid Interface Sci. 2012 Dec 1;185-186:14-33. doi: 10.1016/j.cis.2012.08.007. Epub 2012 Sep 4.
This review article presents the collected recent findings and advancements in understanding and manipulating the electronic properties of the Au/Ag NP system from the standpoint of controlling the characteristics of heterostructured core-shell NPs. The discovery of the electronic transfer effect through analysis of both Ag-Au and Au-Ag type NPs inspired the analysis of the resulting enhanced properties. First, the background on the synthesis and characterization of Ag, Au, Ag-Au, Au-Ag and Au-Ag-Au NPs, which will be used as a basis for studying the electronic transfer and stability properties is presented. Next, Mie Theory is used to inspect the optical properties of the Ag-Au NPs, revealing subtle structural characteristics in these probes, which has implications to the plasmonic properties. This is followed by the inspection of the electronic properties of the Au-Ag NPs primarily through XPS and XANES analysis, revealing the origins of the electronic transfer phenomenon. The unique electronic properties are then revealed to result in improved particle stability in terms of susceptibility to oxidation. Finally, an assessment of the resulting enhanced plasmonic sensing properties is discussed. The results are presented in terms of synthesis technique, material characterization, understanding of the electronic properties and manipulation of those properties to create Au-Ag NPs with enhanced resistance to oxidation and galvanic replacement.
这篇综述文章从控制异质核壳 NPs 特性的角度，介绍了近年来在理解和操纵 Au/Ag NP 系统电子特性方面的最新发现和进展。通过分析 Ag-Au 和 Au-Ag 型 NPs 的电子转移效应的发现，激发了对所产生增强特性的分析。首先，介绍了 Ag、Au、Ag-Au、Au-Ag 和 Au-Ag-Au NPs 的合成和表征背景，这将作为研究电子转移和稳定性特性的基础。其次，Mie 理论用于研究 Ag-Au NPs 的光学特性，揭示了这些探针中细微的结构特征，这对等离子体特性有影响。接下来，通过 XPS 和 XANES 分析主要检查 Au-Ag NPs 的电子特性，揭示了电子转移现象的起源。然后，揭示了独特的电子特性，从而提高了颗粒的氧化敏感性稳定性。最后，讨论了由此产生的增强等离子体传感特性的评估。结果根据合成技术、材料特性、电子特性的理解以及对这些特性的操纵进行呈现，以创建具有增强氧化和电置换抗性的 Au-Ag NPs。
