Tungsten-Disulfide-Based Ultrathin Solar Cells for Space Applications

Two-dimensional (2-D) materials, such as transition metal dichalcogenides (TMDCs), are strong candidates for space photovoltaics as they are very lightweight, flexible, and resilient to ionizing radiation. Here, an ultrathin tungsten disulfide (WS₂) based photovoltaic cell with photon management features has been modeled, with performance improvement from enhanced absorption. Our photovoltaic model consists of a 200 nm thick WS₂-based heterojunction solar cell, similar to the HIT (heterojunction with intrinsic thin layer) solar cell structure, together with a light trapping grating structure and an antireflection coating layer. The photovoltaic cell with an optimized 1-D grating light trapping structure and an appropriate antireflection dielectric coating was demonstrated to give an efficiency above 23% under the AM0 solar spectrum in our model—comparable with other single-junction space photovoltaic cells. The material properties are taken directly from experimentally observed results; the proposed device architecture with additional optical features is based on experimentally fabricated devices and structures and is expected to be resistant to ionizing radiation in the space environment. Our results show that our TMDC-based photovoltaic system with light trapping and antireflection coating is a strong candidate for space photovoltaic applications.