Seed-Mediated Electroless Deposition of Gold Nanoparticles for Highly Uniform and Efficient SERS Enhancement.

Junqi Tang,Haichun Zhou,Shiqing Man,Quanhong Ou,Limin Qi

doi:10.3390/nano9020185

Abstract

A seed-mediated electroless deposition (SMED) approach for fabrication of large-area and uniform gold nanoparticle films as efficient and reproducible as surface-enhanced Raman scattering (SERS) substrates was presented. This approach involved a seeding pretreatment procedure and a subsequent growth step. The former referred to activation of polylysine-coated glass slides in gold seed solution, and the latter required a careful control of the reactant concentration and reaction time. With the aid of gold seeds and appropriate reaction conditions, a large-area and uniform nanofilm with evenly distributed gold nanoparticles (Au NPs) was formed on the surface of the substrates after adding a mixed solution containing ascorbic acid and trisodium citrate. The morphology of the Au nanofilm was examined by scanning electron microscopy. The size evolution of Au NPs on the surface of the substrates was analyzed in detail. The nanofilm substrate was prepared by reaction conditions of the seeded activation process: 10 mL ascorbic acid and trisodium citrate mixture and 30 min of soaking time, which exhibited an excellent uniformity and reproducibility of SERS enhancement with relative standard deviation (RSD) values of less than 8% (particularly, a RSD value of 3% can be reached for the optimized measurement). Compared to the common electroless deposition, the seed-mediated electroless deposition possessed inherent advantages in controllability, reproducibility, and economic benefit.

Highlights

The term “electroless plating” (EP or ELP) is referred to as the spontaneous reduction or in situ reduction of metal ions to the metallic state in the absence of an external source of electric current, which was firstly coined by Brenner and Riddell and is generally referred to as “in-situ chemical reduction”, “chemical deposition” or “electroless deposition” [1,2,3,4]
Some researchers have employed the polylysine-coating glass slide to improve the uniform distribution of the adsorbed nanoparticles [37,38,39]
The large-area and uniform Au NPs films were directly deposited to the seed-modified glass substrate

Summary

Introduction

The term “electroless plating” (EP or ELP) is referred to as the spontaneous reduction or in situ reduction of metal ions to the metallic state in the absence of an external source of electric current, which was firstly coined by Brenner and Riddell and is generally referred to as “in-situ chemical reduction”, “chemical deposition” or “electroless deposition” [1,2,3,4] This method has been widely used for the preparation of metal films on various substrates, such as metal on metal, metal on semiconductor, and metal on insulator [1]. As for other common substrates, such as glass slide, Si wafer, and mica plate, there were many reports about electroless deposition of metal nanoparticles on these substrates [7,8,9,10,11]

Methods

Results

Conclusion