High efficiency Titanium oxides and nitrides ultra-broadband solar energy absorber and thermal emitter from 200 nm to 2600 nm

Solar energy is a widely used clean energy source, and solar absorber with wider spectrum and higher efficiency is more ideal for various applications of solar energy. In this paper, an efficient and ultra-broadband solar absorber is proposed, which is composed of periodic nano-disk combination array on TiO2 thin film. In our work, we use FDTD solutions to simulated and calculated the field distribution, absorption spectrum and thermal radiation intensity of the structure to explore the physical mechanism of the resonator. Among them, the resonance between the polarization direction of the three-layer nano-disk and the plasmon resonance at the junction of TiN nano-disk and TiO2 have obtained the ultra-broadband high-efficiency absorption of the absorber. The absorption bandwidth (A > 90%) reaches 1869 nm (288.5 nm-2157.5 nm), the average absorption efficiency in this range is 96.56%, and the average absorption efficiency in the whole wave band (200–2600 nm) is 93.77%. In addition, the structure has extremely strong heat radiation intensity, with high emission efficiency of 92.83% at 1500 K. Furthermore, the solar absorber proposed by us is polarization independent. In Transverse Electric (TE) mode and Transverse Magnetic (TM) mode, the increase of incident angle causes slight spectral shift of absorption spectrum, and the maximum deviation of average absorption efficiency is 2.17%. Ultra-broad absorption band, high absorption efficiency, high radiation intensity and polarization independence make it competent for thermo-photovoltaics and other high-power optoelectronic, radiation energy and information collection processes.