Improved surface‐enhanced Raman scattering properties of TiO₂ nanoparticles by Zn dopant

Abstract

Abstract In this paper, pure and Zn‐doped TiO 2 nanoparticles (NPs) with various content of Zn were prepared by a sol–hydrothermal method and were employed as active substrates for surface‐enhanced Raman scattering (SERS). On the 3% Zn‐doped TiO 2 substrate, 4‐mercaptobenzoic acid(4‐MBA) molecules exhibit a higher SERS intensity by a factor of 6, as compared with the native enhancement of 4‐MBA adsorbed on undoped TiO 2 NPs. Moreover, the higher SERS activity was still observed on the 3% Zn‐doped TiO 2 NPs at temperature even up to 125 °C. These results indicate that an appropriate amount of Zn doping can improve the SERS performances of TiO 2 SERS‐active substrates. The introduction of Zn dopant can enrich the surface states (defects) of TiO 2 and improve the separation efficiency of photo‐generated charge carriers (electrons and holes) in TiO 2 , according to measurements of X‐ray diffraction, UV‐visible diffuse reflectance spectroscopy, and photoluminescence, which are responsible for the influence of Zn dopant on the improved SERS performances of TiO 2 NPs. Copyright © 2009 John Wiley & Sons, Ltd.