Multilayer stacked ultra-wideband perfect solar absorber and thermal emitter based on SiO2-InAs-TiN nanofilm structure

Abstract

Currently, the application field of sunlight is huge, but the absorption efficiency of solar absorbers for sunlight still needs to be improved. In this paper, we design a solar absorber structure consisting of five cycles of stacked absorber units, where a single absorber unit is a cell consisting of a three-layer SiO2-InAs-TiN film. By stacking the first layer of absorber units on the refractory metal W of the substrate, the subsequent four absorber units reduce the cycles regularly and are stacked sequentially according to our optimized value of 50 nm, and such a design enhances the SPR at the corners of each absorber unit and the Fabry-Perot resonance coupling between absorber units, ultimately achieving the perfect absorption of the absorber in the bandwidth of 2599.5 nm. It is noteworthy that there is an ultra-perfect absorption (A>99%) in the band of 2001 nm. After the finite difference time domain method in time domain (FDTD) calculation, its weighted average absorption (AM1.5) is 99.31%. At 1000 K and 1200 K, the thermal radiation efficiency is 97.35% and 97.83%, respectively. Meanwhile, the structure of the absorber is independent of polarization, and the sun's incidence angle has increased to 60°, but it still achieves an average absorption of 90.83% over the whole wavelength band (280 to 3000 nm). It is worth noting that the innovation of our work lies in the design of a multilayer recycled absorber unit structure, which can efficiently maintain the absorber's absorption bandwidth in the visible-near-infrared wavelength band, and its strong thermal radiation efficiency can also be applied in the field of thermal emitters.