High-efficiency solar metamaterial absorber based on multilayer circular ring arrays

Abstract

Artificially designed tunable metamaterial solar absorbers are an important component of high-performance optoelectronic devices. However, these solar absorbers usually have insufficient absorption bandwidth or absorption efficiency, while the efficiency of solar absorbers in terms of thermal radiation efficiency is low or rarely investigated. This makes it difficult to meet the potential applications of solar absorbers in various aspects. In this paper, we propose a concentric ring array (CRA) metamaterial solar perfect absorber. We use the finite-difference time domain (FDTD) to simulate the structure. The simulation results show that the absorptivity of the plane wave incident vertically at 300–4000 nm is more than 95.8%, and the average absorptivity is 98.93%. This means there is perfect absorption in the bandwidth, which is essential for the complete absorption of solar energy. At the same time, the proposed absorber has excellent process tolerance and material substitutability, which means that the errors in the fabrication process and the lack of materials have little impact on our absorber, allowing the device to be manufactured in large quantities. The integrated absorption of CRA in the Air Mass 1.5 solar spectrum is as high as 98.22%, and it can be up to 99% after adjusting the geometrical parameter, which highlights the advantages of the absorber's process tolerance. In terms of thermal radiation, the proposed structure has a thermal radiation efficiency of more than 99% at 300–2000 K, which improves the low thermal radiation efficiency of previous solar absorbers. The temperature thermal stability study reveals that the CRA can maintain excellent working performance at any temperature. Notably, the perfect absorption is not affected by the polarization and angle of the incident light. The above results make the absorber promising for applications in solar energy collection, infrared imaging, electromagnetic cloaking, and emission.