ABSTRACT
In this paper, a novel type of tunable ultra-wide band and double-narrow band artificial electromagnetic absorption device is studied. This work uses a titanium nitride-titanium-tungsten (TiN-Ti-W) composite ring array, a TiN reflector layer, and a silver-titanium dioxide-silver (Ag-TiO2-Ag) three layer composite structure to prepare the absorption layer. The simulation results illustrate that the absorption rate can reach 96.6% when the absorption wavelength is 300-2800 nm. When the light source is backward incidence, ultra-narrow band absorption can occur at specific wavelengths of 465 nm and 932 nm. This proves that the absorber is in good agreement with the impedance matching theory. The research results of this work will provide a theoretical basis for the design and application of solar thermal energy conversion.
ABSTRACT
In this paper, we design a solar absorber based on the Si3N4-W-Ti-SiO2 insulator-metal-insulator structure and demonstrate it using the finite difference time domain (FDTD) method. The absorption rate of the absorber consisting of a multi-layer structure with cross etching is over 90% in the bandwidth of 500 nm to 2995 nm with an average absorption rate of 98.3%. There are three peaks at 620 nm, 1002 nm and 1761 nm with peak heights of 99.8%, 99.8% and 99.0%, respectively. By analyzing the distribution of electric and magnetic fields in different sections of the absorber, it is found that the physical mechanism of the structure with high absorptivity is due to the interaction of propagating surface plasmon resonance and local surface plasma resonance. The effects of different structural parameters and the angle of incidence of a light source on the absorber absorption are discussed. The absorber can be used in solar thermal systems, thermal photovoltaics and thermoelectronic devices.
