Anti-Reflective Graded-Index Metasurface with Correlated Disorder for Light Management in Planar Solar Cells

Dielectric metasurfaces with tailored disordered have recently emerged as a highly favored light-trapping approach for solar cells compared to traditional techniques like direct nanostructuring and antireflective (AR) coatings. The research interest is due to their superior light-scattering properties, ideal for thin solar cells. Moreover, they successfully overcome the detrimental impact on electrical performance due to texturing and can be produced on macroscopically large wafers using self-assembly nanofabrication methods. This work investigates a graded-index-based design strategy for such disordered metasurfaces where the disordered arrangement is tailored towards a correlated, hyperuniform disorder. Individual scattering elements are designed by drawing inspiration from transformation optics. We numerically and experimentally demonstrate that our disordered graded-index metasurface can significantly improve the light-trapping and antireflective performance of a solar cell stack, especially when compared to structures that implement only one of the two design strategies.