Appealing physical and chemical properties are foreseen in nanoparticles containing immiscible elements, despite their synthesis is challenging due to the unfavorable thermodynamics. Here we show that silver nanoparticles doped with Co can be achieved by a facile one-step route relying on laser ablation in liquid. Structural analysis suggests that the bimetallic nanoparticles consist of a matrix of face-centred cubic Ag rich of cobalt as point defects or dislocations, in a structure that is stable over time even in aqueous solution. This happens despite the complete immiscibility of the two metals at any temperature in the solid and liquid phase, as confirmed also by density functional theory calculations. The nonequilibrium Co-Ag nanoparticles benefit of silver features such as the plasmonic response and the easy surface chemistry with thiolated ligands, combined with the magnetic properties of cobalt. Importantly, plasmonics and magnetism are not quenched after mixing, contrary to what was observed in other bimetallic systems like the Au-Fe one. This opens the way to several technologically relevant applications and, as a proof of concept, we demonstrate magnetophoretic assembly of Co-Ag nanoparticles into arrays of plasmonic dots exploitable for surface-enhanced Raman spectroscopy.

尽管由于不利的热力学，它们的合成具有挑战性，但在包含不溶混元素的纳米颗粒中可以预见到具有吸引力的物理和化学性质。在这里，我们表明，可以通过依赖于液体中激光烧蚀的简便一步法来实现掺杂Co的银纳米颗粒。结构分析表明，双金属纳米颗粒由表面富集钴的面心立方Ag基质（作为点缺陷或位错）组成，即使在水溶液中也能随时间稳定。尽管两种金属在固相和液相中的任何温度下都完全不混溶，但仍会发生这种情况，这也通过密度泛函理论计算得到证实。非平衡Co-Ag纳米颗粒受益于银的特性，例如等离子体响应和硫醇化配体的表面化学特性，以及钴的磁性。重要的是，与其他双金属体系（例如Au-Fe系）中观察到的相反，混合后，等离子体激元和磁性不会被淬灭。这为一些技术上相关的应用开辟了道路，并且，作为概念验证，我们证明了Co-Ag纳米粒子的磁致组装成可用于表面增强拉曼光谱的等离子点阵列。