Numerical simulation of efficient solar absorbers and thermal emitters based on multilayer nanodisk arrays

In this work, we design a solar absorber and thermal emitter with ultra-broadband perfect absorption and high thermal radiation efficiency. The solar absorber has a high absorption efficiency of 91.5 % in the full wavelength range (280-4000 nm), and the weighted average absorption efficiency (AM1.5) is as high as 99 % by the finite difference time domain method (FDTD) simulation calculation. And the absorption bandwidth with absorption efficiency greater than 90 % reaches 2929 nm (280-3209 nm), and the average absorption efficiency in this band is as high as 97.4 %. Such strong absorption is due to the plasmon resonance and near-field coupling of the multilayer nanodisks. In addition to being used in solar absorbers, the structure also has potential applications in thermal emitters. The novelty of this work is to explore the application of the structure in the field of thermal radiation, and the optimal working temperature of the structure for thermal radiation is obtained. Through calculation, we approximately consider that the optimal working temperature of the structure as a thermal emitter is 2000 K, and the thermal radiation efficiency at this temperature is 94.8 %. The structure proposed by us is polarization-independent, insensitive to incident angle changes, the absorption spectra of transverse electric (TE) mode and transverse magnetic (TM) mode are the same, and the absorption efficiency remains 80 % even when the incident angle is increased to 60 degrees. The excellent performance makes the structure widely used in the fields of solar energy absorption and emission.