Importance Of the Use of Natural Hyperbolic Material to Harvest Solar Energy

Abstract

In this paper, we present a novel solar energy harvesting absorber using pyramidal nanostructures made of a naturally
occurring hyperbolic substance. We begin by numerically studying regularly ordered anisotropic and naturally
hyperbolic bismuth telluride (Bi2Te3) on a silver substrate, while the metamaterial is immersed in water. According
to our research, this absorber exhibits a remarkable absorptance of more than 99.9% spanning the 300–2400 nm
wavelength range. By analyzing the absorber's power dissipation density and electric field distribution, we explore
the underlying mechanisms. It turns out that the gradient index effect in the longer wavelength range (1000–2400 nm)
and the slow light effect in the type-II hyperbolic area (300–1000 nm) are essential for attaining complete solar energy
absorption. These samples have an absorptance of up to 97.5%, with the lowest absorptance still surpassing 94% in
the 380–1800 nm wavelength range. In order to verify the mechanics underlying the flawless absorption of solar
energy, we also create and examine more samples. The findings of this work open the door to more efficient solar
energy harvesting through the use of metamaterials with water-submerged nanostructures composed of naturally
occurring hyperbolic materials.