Synthesis of ultra-long gold nanowires via kinetic control of strain-release structural deformation

Abstract

Gold nanomaterials have earned a significant amount of attention due to their biocompatibility and excellent optoelectronic properties, and have been intensely investigated for use in a variety of applications. Since these properties are critically dependent on the size and shape of the nanomaterials, substantial efforts have been made to develop novel methods to fabricate gold nanomaterials with varying structures. However, there is very few reports on the synthesis of gold nanowires (AuNWs), as it is intrinsically hard for gold to endure the strain energy applied in nanowire structure fabrication. The present work demonstrates a new synthetic method for fabricating gold nanowires and their characterization. In this method, gold nanowires are synthesized via a PDDA-mediated polyol process, which effectively controls the kinetics of the reaction to acquire a one-dimensional (1D) structure. From this simple method, I can produce gold nanowires on a milligram scale. Furthermore, the current procedure provides a high yield of gold nanowires and is readily scalable. The synthesized gold nanowires have a diameter of ~ 96 nm, which is relatively thick, and a length of several hundred micrometers. Aberration corrected transmission electron microscopy (Cs-TEM) and in situ synchrotron X-ray absorption spectroscopy were used to characterize the structure and calculate the innate strain of the gold nanowires. Gold nanowires were also microtomed and focused ion beam scanning electron microscopy (FIB-SEM) was used to observe their cross sectional structure. Furthermore, plastic deformation of the gold nanowire structure was detected, which enabled the synthesis of thick gold nanowires.