Fabrication, Characterization, and Application of Large-Scale Uniformly Hybrid Nanoparticle-Enhanced Raman Spectroscopy Substrates.

Jiang Yan,Qingyi Meng,Feng Wei,Chunhui Liu,Qi Qi,Lidong Wu,Xiaoli Zhu,Shuhua Wei,Jing Zhang,Anjie Ming,Lintao Liu,Yanrong Wang

doi:10.3390/mi10050282

Abstract

Surface-enhanced Raman spectroscopy (SERS) substrates with high sensitivity and reproducibility are highly desirable for high precision and even molecular-level detection applications. Here, large-scale uniformly hybrid nanoparticle-enhanced Raman spectroscopy (NERS) substrates with high reproducibility and controllability were developed. Using oxygen plasma treatment, large-area and uniformly rough polystyrene sphere (URPS) arrays in conjunction with 20 nm Au films (AuURPS) were fabricated for SERS substrates. Au nanoparticles and clusters covered the surface of the URPS arrays, and this increased the Raman signal. In the detection of malachite green (MG), the fabricated NERS substrates have high reproducibility and sensitivity. The enhancement factor (EF) of Au nanoparticles and clusters was simulated by finite-difference time-domain (FDTD) simulations and the EF was more than 104. The measured EF of our developed substrate was more than 108 with a relative standard deviation as low as 6.64%–13.84% over 15 points on the substrate. The minimum limit for the MG molecules reached 50 ng/mL. Moreover, the Raman signal had a good linear relationship with the logarithmic concentration of MG, as it ranged from 50 ng/mL to 5 μg/mL. The NERS substrates proposed in this work may serve as a promising detection scheme in chemical and biological fields.

Highlights

Surface-enhanced Raman spectroscopy (SERS), as a promising surface sensitive analytical technique, has attracted intense interest in chemical, biological, and environmental research due to its ultra-sensitivity, high selectivity, and rapid detection capability [1,2,3]
Au nanoparticles and clusters were formed on the surface of the nanoparticle-enhanced Raman spectroscopy (NERS) substrate, and this provided more hot spots to enhance the Raman signal
The uniformly rough polystyrene sphere (URPS) arrays were formed by O2 plasma treatment of PS sphere arrays by using RIE with O2 gas

Summary

Introduction

Surface-enhanced Raman spectroscopy (SERS), as a promising surface sensitive analytical technique, has attracted intense interest in chemical, biological, and environmental research due to its ultra-sensitivity, high selectivity, and rapid detection capability [1,2,3]. To fabricate the ordered nano-array SERS substrates, a great number of techniques have been studied, such as photolithography [15], electron beam lithography [16], X-ray lithography [17], and nanoimprinting [18] These techniques usually have shortcomings of low throughput and high cost. On the basis of their study, we used self-assembly and nanosphere lithography in conjunction with 20 nm Au films to form the nanoparticle-enhanced Raman spectroscopy (NERS) substrate. By this method, Au nanoparticles and clusters were formed on the surface of the NERS substrate, and this provided more hot spots to enhance the Raman signal

Methods

Results

Conclusion