Van der Waals bilayer antimonene: A promising thermophotovoltaic cell material with 31% energy conversion efficiency

Antimonene has recently been theoretically predicted and experimentally demonstrated as a new type of two-dimensional (2D) material with high stability and promising potential for optoelectronic applications. However, it is still a significant and open issue to harvest electromagnetic wave radiation as much as possible and convert it into electricity via antimonene. Here, for the first time, we propose a van der Waals (vdW) stacking strategy of antimonene for thermophotovoltaic (TPV) cells, which could achieve radiation-to-electricity efficiency as high as 31%, exceeding the traditional TPV materials such as Ge and GaSb. The vdW bilayer and trilayer antimonenes with high thermodynamic stability were constructed according to density functional theory (DFT). Surprisingly, among them, the AC-stacking vdW bilayer antimonene exhibited a bandgap of 0.62 eV via Heyd-Scuseria-Ernzerhof hybrid functional (HSE06) containing spin-orbital coupling (SOC), falling into the optimum range of the TPV requirement (0.35-0.75 eV). Such a decisive advantage enables the AC-stacking vdW bilayer antimonene to be a very promising material for high-efficient TPV cell, which has been evidenced by an energy conversion efficiency of 31% for the foremost designed vdW bilayer Sb/AC-based TPV. The concept reported here associated with the recent experimental progress on vdW multilayer antimonene could open the door of high-efficient TPV devices based on 2D materials.