Phonon Confinement Effect in TiO2 Nanoparticles as Thermosensor Materials

TiO2 or ZnO nanoparticles (NPs) have a very strong finite-size dependency in their Raman spectra or photoluminescence (PL) spectra due to the phonon confinement effect or the quantum confinement effect. Together with a fast grain growth kinetics and a high stability under high temperature and pressure, they can forensically retain the complete thermal history of an event. By spatially distributing these NPs during thermal events such as blasts or weapon tests, a spatially and temporally non-uniform thermal environment can be determined by a direct read off their Raman or PL spectra at various locations.