Gold nanoshells on polystyrene cores for control of surface plasmon resonance
Gold nanoshells on polystyrene cores for control of surface plasmon resonance
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DOI：
10.1021/la047628y
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发表时间：
2005-02-15
期刊：
影响因子：
3.9
通讯作者：
Prasad, PN
中科院分区：
文献类型：
--
作者：
Shi, WL;Sahoo, Y;Prasad, PN
提出了一种以单分散聚苯乙烯胶乳纳米球为核，以金纳米粒子为壳的核壳结构的合成方法。在这些结构中使用聚苯乙烯球体作为核心是有利的，因为它们在商业上很容易获得，大小不一，而且其中掺杂了染料或其他分子。用柠檬酸钠或四(羟甲基)氯化膦(THPC)还原前驱体制备的金纳米颗粒，大小从1到20 nm不等。用2-氨基乙硫醇盐酸盐(AET)对聚苯乙烯微球进行官能化处理，使其与表面的羧酸基形成多肽键，形成端硫醇表面。然后，金纳米颗粒与硫醇基团结合，提供高达约50%的表面覆盖率。这些纳米颗粒作为种子，通过还原额外的金前体来生长连续的金壳。壳层厚度和粗糙度可以通过纳米颗粒种子的大小以及它们生长成连续的壳层的过程来控制。通过改变乳胶核的相对尺寸和金覆盖层的厚度，纳米壳层的等离子体共振可以调节到电磁光谱的可见光和红外范围内的特定波长，用于从构建光子晶体到生物光子学的各种应用。用扩展的Mie散射理论很好地预测了等离子体共振消光峰的位置和宽度。
A method is presented for synthesizing core-shell structures consisting of monodisperse polystyrene latex nanospheres as cores and gold nanoparticles as shells. Use of polystyrene spheres as the core in these structures is advantageous because they are readily available commercially in a wide range of sizes, and with dyes or other molecules doped into them. Gold nanoparticles, ranging in size from 1 to 20 run, are prepared by reduction of a gold precursor with sodium citrate or tetrakis(hydroxymethyl)phosphonium chloride (THPC). Carboxylate-terminated polystyrene spheres are functionalized with 2-aminoethanethiol hydrochloride (AET), which forms a peptide bond with carboxylic acid groups on their surface, resulting in a thiol-terminated surface. Gold nanoparticles then bind to the thiol groups to provide up to about 50% coverage of the surface. These nanoparticles serve as seeds for growth of a continuous gold shell by reduction of additional gold precursor. The shell thickness and roughness can be controlled by the size of the nanoparticle seeds as well as by the process of their growth into a continuous shell. By variation of the relative sizes of the latex core and the thickness of the gold overlayer, the plasmon resonance of the nanoshell can be tuned to specific wavelengths across the visible and infrared range of the electromagnetic spectrum, for applications ranging from the construction of photonic crystals to biophotonics. The position and width of the plasmon resonance extinction peak are well-predicted by extended Mie scattering theory.