Ag Nanorods Coated with Ultrathin TiO2 Shells as Stable and Recyclable SERS Substrates.

Lingwei Ma,Mengjing Hou,Yu Huang,Zheng Xie,Zhengjun Zhang

doi:10.1038/srep15442

Abstract

TiO2-coated Ag nanorods (Ag@TiO2 NRs) have been fabricated as multifunctional surface-enhanced Raman scattering (SERS) substrates. Uniform TiO2 shells could sufficiently protect the internal Ag NRs against oxidation and sulfuration, thus the temporal stability of SERS substrates was markedly improved. Meanwhile, due to the synergetic effect between crystalline TiO2 and Ag, the nanocomposites could clean themselves via photocatalytic degradation of the adsorbed molecules under ultraviolet irradiation and water dilution, making the SERS substrates renewable. Such Ag@TiO2 NRs were shown to serve as outstanding SERS sensors featuring high sensitivity, superior stability and recyclability.

Highlights

TiO2-coated Ag nanorods (Ag@TiO2 NRs) have been fabricated as multifunctional surface-enhanced Raman scattering (SERS) substrates
We found that the substrates coated by different atomic layer deposition (ALD) cycles showed no visible structure variation observed from the SEM resolution, which might be due to the ultrathin nature of the deposited TiO2 layers
We should note that the measurement of different molecules did not influence each other since only the Raman peaks of the adsorptive molecules were discovered other than any impurity peaks. These results suggest that the Ag@TiO2 composites were feasible to act as recyclable SERS substrates for the detection of organic species such as crystal violet (CV) and methylene blue (MB), and show great potential for further sensitive and reusable SERS applications[13,26,28]

Summary

Introduction

TiO2-coated Ag nanorods (Ag@TiO2 NRs) have been fabricated as multifunctional surface-enhanced Raman scattering (SERS) substrates. Due to the synergetic effect between crystalline TiO2 and Ag, the nanocomposites could clean themselves via photocatalytic degradation of the adsorbed molecules under ultraviolet irradiation and water dilution, making the SERS substrates renewable Such Ag@ TiO2 NRs were shown to serve as outstanding SERS sensors featuring high sensitivity, superior stability and recyclability. What’s more, the self-cleaning ability stems from the ultraviolet (UV) light-induced degradation of analytes via the synergetic effect of TiO2 shells and Ag NRs, i.e., subsequent to SERS measurements, the substrates can be purified by UV irradiation and be reused for further Raman analyses This self-cleaning function offers an opportunity to eliminate the single-use shortcoming of most conventional SERS substrates and reduce the SERS measurement costs as well

Methods

Results

Conclusion