Heat-assisted hot-hole transfer increases the surface-enhanced Raman activity of Au-TiO2 nanoarrays

Abstract

Abstract Monitoring the evolution of molecules during photo and thermal synergistically induced physical and chemical processes is of paramount interest in fields including chemical, material, and energy research. Surface-enhanced Raman spectroscopy (SERS) is a highly promising technology in this regard, offering advantages of sensitivity, real-time, and label-free detection. However, the application of conventional SERS in high-temperature environments has faced challenges due to the inevitable loss of activity and decline in sensitivity. Herein, we synthesize Au-TiO 2 nanoarrays as SERS substrates, and an anomalous enhancement of Raman signal with increasing temperature is observed. The signal intensity increases by 11.41 times at 180 °C compared to that at 22 °C. This high-temperature enhancement in Raman activity is attributed to an underlying mechanism: heat-assisted hot-hole transfer, which enables 785 nm photon-induced hot-hole transfer from Au to TiO 2 . Our work expands the application of the SERS technique for high-temperature chemical analysis and molecular diagnostics.