Raman Spectroscopy of Tungsten Trioxide in the Temperature Range 30.6–170 ̊C and COMSOL Simulations of a Heated Sample Cell of Relevance to Gas Sensor Technology

The goal of this study is to characterize the Raman spectra of tungsten trioxide (WO3) at increasing temperatures in the range 30.6–170 ̊C in order to understand the behavior and characteristics of WO3 after adsorption of toxic gases (e.g. NO and SO2) and to provide a database of Raman spectral features for future use in providing an optical complement to semi-conducting metal oxide gas sensor technology. Raman spectra of WO3 were collected at increasing temperatures from 30.6–170 ̊C using a DXR Smart Raman Spectrometer with a 780 nm laser. The red shifting of the Raman peaks is attributed to thermal expansion and changing phonon interactions. Recording WO3's reaction to increased temperature will make it possible to identify toxic gases at different temperatures through Raman spectroscopy. To monitor the temperature of the WO3 more precisely, a surface thermometer is used and COMSOL Multiphysics® simulation software is used to model the temperature at the surface of the Ventacon H-4-200 Hot Cell used to heat the sample. Simulation will allow for better understanding of the temperature dependent changes in the Raman spectra.