Herein, a poly(vinylpyrrolidone) (PVP)‐free method is described for synthesizing Ag nanoplates that have localized surface plasmon resonance in the near‐infrared (NIR) range. Citrate‐capped Ag spherical nanoparticles are first grown into small Ag nanoplates that resonate in the range of 500–800 nm. The small Ag nanoplates are used as seeds to further grow into large Ag nanoplates with a lateral dimension of 100–600 nm and a plasmon resonance wavelength of 800–1660 nm and above. The number of growth steps can be increased as desired. Without introducing additional citrate into the solutions of small Ag nanoplate seeds, large Ag nanoplates can be synthesized within minutes. The entire synthesis is completely PVP free, which promotes the nanoparticle growth along the lateral direction to form large Ag nanoplates. The multistep growth and the minimum usage of citrate are essential for the fast growth of high‐aspect‐ratio Ag nanoplates resonating in the NIR range.

中文翻译：

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不含聚乙烯吡咯烷酮的多步合成近红外范围内等离子共振的银纳米板

本文介绍了一种不含聚乙烯吡咯烷酮（PVP）的方法，用于合成在近红外（NIR）范围内具有局部表面等离子体共振的Ag纳米板。柠檬酸盐封端的Ag球形纳米颗粒首先生长在500-800 nm范围内共振的小型Ag纳米板上。小型Ag纳米板被用作种子，以进一步生长成横向尺寸为100–600 nm，等离振子共振波长为800–1660 nm及以上的大型Ag纳米板。可以根据需要增加生长步骤的数量。无需将额外的柠檬酸盐引入到小型Ag纳米板种子的溶液中，就可以在数分钟内合成大型Ag纳米板。整个合成过程完全不含PVP，从而促进了纳米颗粒沿横向方向的生长，从而形成了较大的Ag纳米板。