Optical manipulation of plasmonic nanoparticles provides opportunities for fundamental and technical innovation in nanophotonics. Optical heating arising from the photon-to-phonon conversion is considered as an intrinsic loss in metal nanoparticles, which limits their applications. We show here that this drawback can be turned into an advantage, by developing an extremely low-power optical tweezing technique, termed opto-thermoelectric nanotweezers. By optically heating a thermoplasmonic substrate, a light-directed thermoelectric field can be generated due to spatial separation of dissolved ions within the heating laser spot, which allows us to manipulate metal nanoparticles of a wide range of materials, sizes and shapes with single-particle resolution. In combination with dark-field optical imaging, nanoparticles can be selectively trapped and their spectroscopic response can be resolved in situ. With its simple optics, versatile low-power operation, applicability to diverse nanoparticles and tunable working wavelength, opto-thermoelectric nanotweezers will become a powerful tool in colloid science and nanotechnology.

等离子体纳米粒子的光学操纵为纳米光子学的基础和技术创新提供了机会。光子到声子转换产生的光热被认为是金属纳米颗粒的固有损耗，这限制了它们的应用。我们在这里表明，通过开发一种极低功率的光镊技术（称为光热电纳米镊子），可以将这一缺点转化为优势。通过光学加热热等离子体基底，由于加热激光点内溶解离子的空间分离，可以产生光导向热电场，这使我们能够用单粒子操纵各种材料、尺寸和形状的金属纳米颗粒解决。与暗场光学成像相结合，可以选择性地捕获纳米颗粒，并可以原位解析它们的光谱响应。凭借其简单的光学器件、多功能的低功耗操作、对多种纳米粒子的适用性和可调谐的工作波长，光热电纳米镊子将成为胶体科学和纳米技术中的强大工具。