Theoretical Insights into Enhanced Photothermal Efficiency in Titanium Oxynitride

Abstract

A comprehensive theoretical framework integrating density functional theory (DFT) and finite‐difference time‐domain (FDTD) simulations to investigate absorption and photothermal properties of titanium oxynitride (TiON) is presented. DFT‐calculated dielectric data combined with theoretical estimations of effective thermal properties and mass density are used to predict absorption spectra and light‐induced temperature rise in TiON metamaterials and slabs. It is shown that a two‐layer nanoring metamaterial with moderate oxygen doping achieves over 95% absorption across the 550–1500 nm range due to the interplay between localized surface plasmon resonance and intrinsic TiON losses. This leads to enhanced photothermal heating effects in the TiON metamaterials compared to the TiON slab. The findings reveal that there exists an optimal oxygen doping level in TiON, where the photothermal efficiency is maximized due to a balance between enhanced absorption and reduced thermal conductivity. These results are consistent with prior works and provide insights into tailoring TiON for diverse solar energy applications.