Ultrafast Photoinduced Heat Generation by Plasmonic HfN Nanoparticles

There is great interest in the development of alternatives to noble metals for plasmonic nanostructures. Transition metal nitrides are promising due their robust refractory properties. However, photophysics these nanostructures, particularly hot carrier dynamics and photothermal response on ultrafast timescales, not well understood. This limits implementation applications such as catalysis or solar thermophotovoltaics. In this study, light-induced relaxation processes water-dispersed HfN nanoparticles are, first time, elucidated by fs transient absorption, Lumerical FDTD COMSOL Multiphysics simulations, temperature-dependent ellipsometry. It unequivocally demonstrated that convert absorbed photons into heat within <100 fs; no signature charge carriers observed. Interestingly, under high photon energy intense irradiation stimulated Raman scattering characteristic oxynitride surface termination These findings suggest transition could offer benefits over field catalysis.