用于将纳米颗粒集合体沉积为固体基底上的限定图案的常规基于模板的方法的局限性要求开发不需要模板或光刻掩模的技术。使用光学诱导的热梯度驱动胶体朝向或远离激光光斑的迁移,称为光热电泳,已显示出各种胶体物种的低功率捕获和光学操纵的希望。然而,迄今为止,使用这种技术的胶体印刷尚未建立。在这里,一种光学导向印刷贵金属纳米粒子的方法,特别是金纳米球的报道。聚合物聚乙烯吡咯烷酮和金纳米球朝向激光点的热泳导致纳米颗粒聚集体的沉积,能够用作表面增强拉曼散射基底。加热激光功率和聚合物浓度的影响,盐,和表面活性剂对纳米粒子沉积速率和结构的印刷图案进行了研究,表明各种条件都可以允许印刷,暗示了对不同纳米颗粒成分的简单概括,尺寸,和形状。这些发现将极大地有利于未来的努力定向纳米粒子组装,并驱动传感应用,光热加热,以及在生物医学和设备中的相关应用。
The limitations of conventional template-based methods for the deposition of nanoparticle assemblies into defined patterns on solid substrates call for the development of techniques that do not require templates or lithographic masks. The use of optically-induced thermal gradients to drive the migration of colloids toward or away from a laser spot, known as opto-thermophoresis, has shown promise for the low-power trapping and optical manipulation of a variety of colloidal species. However, the printing of colloids using this technique has so far not been established. Herein, a method for the optically directed printing of noble metal nanoparticles, specifically gold nanospheres is reported. The thermophoresis of the polymer polyvinylpyrrolidone and gold nanospheres toward a laser spot led to the deposition of nanoparticle aggregates, capable of serving as surface-enhanced Raman scattering substrates. The influence of heating laser power and the concentrations of polymer, salt, and surfactant on the nanoparticle deposition rate and structure of the printed pattern are studied, showing that a variety of conditions can permit printing, suggesting facile generalization to different nanoparticle compositions, sizes, and shapes. These findings will greatly benefit future efforts for directed nanoparticle assembly, and drive applications in sensing, photothermal heating, and relevant applications in biomedicine and devices.