Investigation of a double-patterned TiN architecture for ultra-wideband solar absorption and thermal emission

Abstract

With the growing global energy crisis, the development of efficient solar absorbers has become increasingly important. In this work, a broadband solar absorber based on a double-patterned TiN architecture is proposed and numerically investigated using the finite-difference time-domain (FDTD) method. The absorber consists of a Ti substrate, a TiN grating layer, a SiO₂ dielectric spacer, and a TiN microstructure array. Simulation results show that the proposed structure exhibits absorptivity above 90% over the wavelength range of 250–3110 nm, corresponding to an ultra-broad bandwidth of 2860 nm. The average absorptivity reaches 96.42%, and the AM1.5-weighted solar absorption efficiency is 95.7%, with an energy loss of only 4.3%. Electromagnetic field analysis indicates that the excellent broadband absorption originates from the synergistic effects of localized surface plasmon resonance, Fabry–Perot cavity resonance, and multimode coupling. In addition, the absorber maintains absorptivity above 90% for incident angles from 0° to 60°, demonstrating good angular stability and polarization insensitivity. Thermal radiation analysis further confirms its promising high-temperature performance. Owing to its excellent absorption capability, structural simplicity, and potential thermal robustness, the proposed absorber shows considerable potential for applications in solar–thermal energy harvesting, desalination, photovoltaics, and thermophotovoltaic systems.