Gold nanoparticles combined with ultrafine TiO₂ layer: a reliable probe for Raman thermometry

Temperature determination methods in metal nanoparticles are essential for providing information on energy dissipation dynamics in such systems and for temperature-sensitive applications, hence the need for high-performance thermometry techniques is evident. In this study, we propose new efficient probes for Raman antiStokes-Stokes thermometry based on gold nanoparticles (AuNPs), prepared by thermal dewetting and controllably functionalized with a 2 nm TiO₂ layer by the sol-gel method. AuNPs@TiO₂ demonstrated good stability and a usable response over a temperature range from 25 °C to 240 °C generated by external thermal and thermoplasmonic heating of the sample. We validate the methodology by taking into account the spectral efficiency of the Raman spectrometer as well as the extinction properties of AuNPs@TiO₂ in the calculations. This approach enables us to propose a reliable temperature measurement over two hundred degrees range.