High-Yield Synthesis of Uniform Ag Nanowires with High Aspect Ratios by Introducing the Long-Chain PVP in an Improved Polyol Process

Jie-Jun Zhu,Guang-Hou Wang,Min Han,Cai-Xia Kan,Jian-Guo Wan

doi:10.1155/2011/982547

Abstract

Polyvinyl pyrrolidone (PVP) with different molecular weights was used as capping agent to synthesize silver nanowires through a polyol process. The results indicated that the yields and aspect ratios of silver nanowires were controlled by the chain length of PVP and increased with increasing the molecular weight (MW) of PVP. When the long-chain PVP-K90 (MW = 800,000) was used, the product was uniform in size and was dominated by nanowires with high aspect ratios. The growth mechanism of the nanowires was studied. It is proposed that the chemical adsorption of Ag+on the PVP chains at the initial stage promotes the growth of Ag nanowires.

Highlights

Nanometer-sized noble metals are of great interest for their unique properties [1,2,3], and for their potential applications in the fields of biomedical diagnostics [4], catalysis [5], optical devices [6], and data storage [7]
The results indicated that the yields and aspect ratios of silver nanowires were controlled by the chain length of Polyvinyl pyrrolidone (PVP) and increased with increasing the molecular weight (MW) of PVP
It was found that both yields and aspect ratios of the obtained Ag nanowires synthesized at T = 150◦C and R = 1 increased with increasing the MW of PVP

Summary

Introduction

Nanometer-sized noble metals are of great interest for their unique properties [1,2,3], and for their potential applications in the fields of biomedical diagnostics [4], catalysis [5], optical devices [6], and data storage [7]. Ag nanostructures have yielded a great deal of literature featuring on the anisotropic growth of crystals into defined morphologies, ranging from nanowires, nanorods, nanoplates, nanocubes, and branched multipods to highly faceted particles [13, 26,27,28,29] Among these methods, the common chemical reduction method based on the polyol process, which is convenient, versatile, and low costing, is usually adopted for the synthesis of noble metal nanoparticles. We successfully synthesized large-scale uniform silver nanowires with high aspect ratios by introducing the long-chain PVP (MW = 800000) in an improved polyol process and investigated the effect of PVP molecular weight on the synthesis of Ag nanowires. The morphological evolution of the Ag nanostructures at various PVP molecular weights was studied in detail, and the growth mechanism of Ag nanowires is proposed linking both the structural characteristics of Ag nanostructures and the roles of PVP surfactants

Experimental

Results and Discussion

Conclusions