Abstract The yolk-shell structure is a good choice for surface-enhanced Raman scattering (SERS) substrate because the monomer has a dimer property which can create nanogaps with a strong electromagnetic field distribution. However, the existing yolk-shell structures are mostly synthesized on the basis of nanospheres, and there are few reports on the regulation of their optical properties. Compared with other structures, nanostar has emerged as one of the best morphologies for producing SERS because it has more “hot spots” on the branches. This article has synthesized a star-shaped bimetallic yolk-shell structure-AuAg@AuAg yolk-shell nanostar, which has the dual characteristics of the branches and the core-shell structure. It is shaped like a hand with a glove that extends over the hand and only partially covers the fingers, so we also call it “Magic mitt”. And we have adjusted its optical properties by changing the number of branches of the yolk, the thickness of the hollow middle layer and the thickness of the outer shell in this structure. AuAg@AuAg yolk-shell nanostar has shown excellent performance for the improved SERS of rhodamine 6G because of greater coupling between yolk and shell, larger specific surface area, more sufficient particle aggregation, and the blocking effect of the outer shell. The best SERS enhancement factor (EF) of the AuAg@AuAg yolk-shell nanostars for R6G is 1.223 × 106.

中文翻译：

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“魔术手套”：形态可控的 AuAg@AuAg 蛋黄壳纳米星，具有更好的等离子体光学特性

摘要 蛋黄壳结构是表面增强拉曼散射 (SERS) 基底的理想选择，因为单体具有二聚体特性，可以产生具有强电磁场分布的纳米间隙。然而，现有的蛋黄-壳结构大多是在纳米球的基础上合成的，对其光学性质的调控鲜有报道。与其他结构相比，纳米星已经成为产生 SERS 的最佳形态之一，因为它在分支上有更多的“热点”。本文合成了一种星形双金属蛋黄壳结构——AuAg@AuAg蛋黄壳纳米星，它具有分支和核壳结构的双重特性。它的形状像一只手，手套覆盖在手上，仅部分覆盖手指，所以我们也称它为“魔术手套”。并且我们通过改变蛋黄的分支数量、中空中间层的厚度和外壳的厚度来调整它的光学特性。AuAg@AuAg蛋黄-壳纳米星由于蛋黄和壳之间的耦合更大、比表面积更大、颗粒聚集更充分以及外壳的阻挡作用，在改善罗丹明6G的SERS方面表现出优异的性能。用于 R6G 的 AuAg@AuAg 蛋黄壳纳米星的最佳 SERS 增强因子 (EF) 为 1.223 × 106。AuAg@AuAg蛋黄-壳纳米星由于蛋黄和壳之间的耦合更大、比表面积更大、颗粒聚集更充分以及外壳的阻挡作用，在改善罗丹明6G的SERS方面表现出优异的性能。用于 R6G 的 AuAg@AuAg 蛋黄壳纳米星的最佳 SERS 增强因子 (EF) 为 1.223 × 106。AuAg@AuAg蛋黄-壳纳米星由于蛋黄和壳之间的耦合更大、比表面积更大、颗粒聚集更充分以及外壳的阻挡作用，在改善罗丹明6G的SERS方面表现出优异的性能。用于 R6G 的 AuAg@AuAg 蛋黄壳纳米星的最佳 SERS 增强因子 (EF) 为 1.223 × 106。