Improved Surface-Enhanced Raman Scattering Properties of ZrO2 Nanoparticles by Zn Doping.

Peng Ji,Zhu Mao,Xiangxin Xue,Xiumin Shi,Zhe Wang,Yu Zhang,Jiaao Lv

doi:10.3390/nano9070983

Abstract

In this study, ZrO2 and Zn–ZrO2 nanoparticles (NPs) with a series of Zn ion doping amounts were synthesized by the sol-gel process and utilized as substrates for surface-enhanced Raman scattering (SERS). After absorbing the probing molecule 4–mercaptobenzoic acid, the SERS signal intensities of Zn–ZrO2 NPs were all greater than that of the pure ZrO2. The 1% Zn doping concentration ZrO2 NPs exhibited the highest SERS enhancement, with an enhancement factor (EF) value of up to 104. X-ray diffraction, X-ray photoelectron spectroscopy, Ultraviolet (UV) photoelectron spectrometer, UV–vis spectroscopy, Transmission Electron Microscope (TEM), and Raman spectroscopy were used to characterize the properties of Zn–ZrO2 NPs and explore the mechanisms behind the SERS phenomenon. The charge transfer (CT) process is considered to be responsible for the SERS performance of 4–MBA adsorbed on Zn–ZrO2. The results of this study demonstrate that an appropriate doping ratio of Zn ions can promote the charge transfer process between ZrO2 NPs and probe molecules and significantly improve the SERS properties of ZrO2 substrates.

Highlights

Since it was first discovered in 1974, surface-enhanced Raman scattering (SERS) has been considered to be an effective and promising spectroscopic technique [1]
We fabricated ZrO2 and Zn–ZrO2 NPs with different Zn-doping concentrations as SERS substrates with the sol-gel method
The findings of this study show that the doped Zn ions significantly improve the SERS properties of ZrO2 NPs, and that the 1% Zn doping concentration NPs exhibit the highest SERS enhancement on the surface-adsorbed probe molecule

Summary

Introduction

Since it was first discovered in 1974, surface-enhanced Raman scattering (SERS) has been considered to be an effective and promising spectroscopic technique [1]. Since a better understanding of the mechanisms of the SERS phenomenon will benefit investigating SERS substrates, researchers are committed to exploring the mechanisms behind the enhancement of the SERS effect. The most likely explanations are electromagnetic mechanisms (EM), as well as chemical mechanisms (CM) due to the charge transfer (CT) process between the probe molecules and substrate [11,12,13,14,15,16]. The primary mechanism of the SERS phenomenon is likely the CT process. The number of semiconductor substrates is still limited, and the enhancement mechanism of SERS still needs further investigation

Methods

Results

Conclusion