Study of Charge Transfer Contribution in Surface-Enhanced Raman Scattering (SERS) Based on Indium Oxide Nanoparticle Substrates

Surface-enhanced Raman scattering (SERS) has outstanding merits in biochemical molecular analysis, and the development of new SERS substrates is the focus of research. Herein, In2O3 nanoparticles (NPs) were synthesized by a high temperature pyrolysis method with cubic phase and small particle size at 10 nm. The structures and properties of In2O3 NPs were characterized by X-ray powder diffraction (XRD), transmission electron microscope (TEM) and other characterization methods. Additionally, the SERS spectra of In2O3-MBA with the enhancement factor (EF) up to 1.22 × 104 is discussed. The results demonstrate that there is a charge transfer (CT) effect revealed between the adsorbed molecules of 4-mercaptobenzoic acid (4-MBA) and the substrates of In2O3 NPs, and it could be excited by long wavelength energy. Based on the In2O3 NPs, the study is beneficial to develop more potential semiconductor SERS substrates.