Microsphere-assisted manipulation of a single Ag nanowire

Metal nanowires are promising building blocks for optoelectronic nanodevices, so their independent and precise manipulation is urgently needed. However, the direct optical manipulation methods are severely hampered due to the high absorption and scattering characteristics of the metal nanowires. Here, a microsphere-assisted indirect optical manipulation method is proposed, and precise manipulation of a single Ag nanowire is demonstrated in liquid. The microsphere is actuated to rotate to generate a microvortex by dynamic optical traps. Under the action of shear stress, the Ag nanowire within the microvortex can be controllably rotated and accurately orientated. By manipulating the position of the microsphere using a single optical trap, a precise positioning of the nanowire can be achieved under the action of pushing force. On this basis, the Ag nanowire-based structures were assembled. This indirect optical manipulation avoids the direct interaction between the light and the nanowires, which makes it independent of both the laser (power, wavelength) and the nanowire (material, size, and shape). Hence, the microsphere-assisted manipulation method is simple and general for independent and precise manipulation of a single nanowire, which is of great significance to the fabrication of optoelectronic nanodevices.