Understanding light absorption realized among nanopillar-structured Sb2S3 thin-film solar cells for seeking high performance

Because of the quasi-1D crystal structure, antimony sulfide (Sb2S3) exhibits low symmetry and complex deep defects, which result in a relatively inefficient carrier collection and slow progress in efficiency improvements. Introducing nanostructures into Sb2S3 thin film technology may be a useful method to decouple the light absorption path and carrier collection path, allowing the use of a very thin light absorption layer, which can boost a more efficient carrier collection. In this work, the light absorption behaviors among the nanopillar-structured Sb2S3 units have been studied by carrying out finite element simulations, constructed on the Mo-coated or uncoated glass substrates. When the length of the nanopillar is large enough or the radius is small enough, making the nanopillar more like a slim nanowire, the in-coupling mode usually works positively on the absorption enhancement, especially during the long-wavelength range. Besides, among a very high density of nanopillar units usually boosts light scattering absorption. These results provide a practical guide to design and fabricate nano-structured Sb2S3 thin-film solar cells by using very thin light absorption layers, thus efficiently enhancing carrier collection, for high performance.