Inverted pyramidally-textured PDMS antireflective foils for perovskite/silicon tandem solar cells with flat top cell

Perovskite/silicon tandem solar cells (TSCs) have the potential to achieve power conversion efficiency exceeding 30%. To be compatible with high-efficiency solution-deposited perovskite top cell, a planar front surface for silicon bottom cell is generally required. However, flat front surfaces result in large light reflection losses and thus reduce the performance of tandem device. To boost light absorption, we design light management antireflective foils made from polydimethylsiloxane (PDMS) polymer carrying random-pyramidal textures with three different pyramid size ranges (1-3 mu m 3-8 mu m, 8-15 mu m). The optical properties, together with the reflection behavior applied to perovskite/silicon tandem solar cells have been systematically studied. One of the PDMS layer exhibited a relatively strong light-scattering property with a high average haze ratio originated from synergistic effect of the appropriate pyramid size and the uneven random pyramid distribution. Consequently, the short-circuit current density of the tandem device was improved by 1.72 mA/cm(2) and thus its efficiency increased from 19.38% to 21.93%, after laminating the PDMS-based antireflection coating (ARC) onto the front surface of tandem device. Furthermore, this work provides a facile and cost-effective way to introduce light-management foils and indicates a broad strategy to enhance the performance of solar cells with planar front surface.