Microsphere-assisted manipulation of a single Ag nanowire

Weina Zhang,Mingcong Wen,Hongxiang Lei,Guowei Yang,Pu Liu

doi:10.1515/nanoph-2021-0234

Abstract

Abstract 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.

Highlights

The independent and precise manipulation of nanostructures is a prerequisite for fully exploiting the potential of nanodevices in various applications [1,2,3,4,5,6], especially for the anisotropic nanostructures, nanowires for example [2,3,4,5], of which the chemical and physical properties are highly dependent to their orientation and position [7, 8]
A microsphere-assisted indirect optical manipulation method is proposed, and precise manipulation of a single Ag nanowire is demonstrated in liquid
Several nanowire manipulation techniques have been investigated based on the magnetic field [9], electric field [10, 11], optical field [12, 13], and others [14, 15], most of which were performed in a liquid environment to prevent the adhesion of nanowires to substrates

Summary

Introduction

The independent and precise manipulation of nanostructures is a prerequisite for fully exploiting the potential of nanodevices in various applications [1,2,3,4,5,6], especially for the anisotropic nanostructures, nanowires for example [2,3,4,5], of which the chemical and physical properties are highly dependent to their orientation and position [7, 8]. The optical field-based manipulation technique, represented by optical tweezers [16], has attracted widespread attention for its high precision, great flexibility, and versatility, and succeeded in trapping and manipulating various nanowires, such as SnO2, Ag, Au, and Si nanowires [12, 17,18,19]. The high photothermal effect resulting from the high absorption of light by the metal nanowires will reduce the stability of the manipulation Another manipulation technique was based on the plasmonic tweezers [18]. Taking 10-μm-diameter SiO2 microspheres as an example, under their “command”, the rotation, orientation, and translation of a single Ag nanowire were achieved This indirect optical manipulation method was further used in manipulating nanowires with different types, sizes, and shapes, proving the universality of this method. The method combined microflow and optical field-based manipulation, which provides a new perspective on the nanostructure assembly and adjustment

Experiment

Working principle

Results and discussion

Conclusion