Parakh Abhinav, Kiani Mehrdad Toussi, Lindgren Emily, Colmenares Anabelle, Lee Andrew Curtis, Suzuki Yuri, Gu Xun Wendy
Department of Materials Science and Engineering, Stanford University Stanford CA 94305 USA.
Materials Engineering Division, Lawrence Livermore National Laboratory Livermore CA 94550 USA.
RSC Adv. 2023 Oct 18;13(43):30491-30498. doi: 10.1039/d3ra06093d. eCollection 2023 Oct 11.
Colloidal nanoparticles can be coated with a conformal shell to form multifunctional nanoparticles. For instance, plasmonic, magnetic, and catalytic properties, chemical stability and biocompatibility can be mixed and matched. Here, a facile synthesis for depositing metal boride amorphous coatings on colloidal metallic nanocrystals is introduced. The synthesis is independent of core size, shape, and composition. We have found that the shell synthesis is limited to nanoparticles capped with short molecular weight and low binding energy ligands, and does not work with polyvinylpyrrolidone (PVP)-coated Ag nanoparticles or thiol-coated Au nanoparticles. Shell thickness can be as thin as 3 nm with no apparent pinholes. High pressure studies show that the coatings are highly resistant to crystallization and are strongly bonded to the crystalline core. By choosing either CoB or NiB for the coating, the composite nanoparticles can be either ferromagnetic or paramagnetic at room temperature, respectively.
胶体纳米颗粒可以包覆一层保形壳层以形成多功能纳米颗粒。例如，等离子体、磁性和催化性质、化学稳定性和生物相容性可以进行混合搭配。在此，介绍了一种在胶体金属纳米晶体上沉积金属硼化物非晶涂层的简便合成方法。该合成方法与核心尺寸、形状和组成无关。我们发现壳层合成仅限于用低分子量和低结合能配体包覆的纳米颗粒，不适用于聚乙烯吡咯烷酮（PVP）包覆的银纳米颗粒或硫醇包覆的金纳米颗粒。壳层厚度可薄至3纳米且无明显针孔。高压研究表明，这些涂层对结晶具有高度抗性，并且与晶体核心紧密结合。通过选择CoB或NiB作为涂层，复合纳米颗粒在室温下分别可以是铁磁性或顺磁性的。
