The creation of SERS‐active substrates is investigated by self‐assembling hierarchical structures of plasmonic‐assisted nanospheres (HSNs). The hierarchical architecture exploits the advantages of the well‐known ordered configuration of a hexagonally closed‐packed array (CPA) of nanospheres. A further layer of upper nanospheres is used to provide regular and intense surface hotspots, located at the nanogaps between neighboring nanospheres. Numerical analysis is carried out to predict the SERS performances and to identify the more promising configurations, by offering design criteria and a physical insight on the conditions affecting the SERS response of the self‐assembled substrates. Two alternative self‐assembly fabrication methods have been pursued to realize HSNs, namely co‐deposition and sequential deposition. Morphological analysis revealed the formation of well‐ordered hierarchical structures with different ratios between the diameters of the bottom and upper nanospheres. Experimental analysis of the SERS response demonstrates that HSNs can work as cost‐effective SERS substrates with superior performances with respect to the simpler single‐layer CPA configurations.

中文翻译：

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自组装分层纳米结构：迈向工程化 SERS 主动平台

通过等离子体辅助纳米球 (HSN) 的自组装分层结构来研究 SERS 活性基底的创建。分层结构利用了众所周知的纳米球六角密堆积阵列（CPA）有序配置的优势。上层纳米球的另一层用于提供规则且强烈的表面热点，位于相邻纳米球之间的纳米间隙处。通过提供设计标准和对影响自组装基底 SERS 响应的条件的物理见解，进行数值分析来预测 SERS 性能并确定更有前途的配置。为了实现 HSN，人们采用了两种替代的自组装制造方法，即共沉积和顺序沉积。形态分析揭示了底部和上部纳米球直径之间具有不同比率的有序分层结构的形成。 SERS 响应的实验分析表明，与更简单的单层 CPA 配置相比，HSN 可以作为经济高效的 SERS 基底，具有优越的性能。