Newly-Developed Broadband Anti-Reflective Nanostructure by Coating Low-index MgF2 Film onto a SiO2 Moth-eye Nano-pattern.

Newly developed nanopatterned broadband antireflective (AR) coating was fabricated on the front side of a glass/indium-tin-oxide (ITO)/perovskite solar cell (PSC) by depositing a single interference layer onto a two-dimensional (2D) patterned moth-eye-like nanostructure. The optimized developed AR nanostructure was simulated in a finite-difference-time-domain (FDTD) analysis. To realize the simulated developed AR nanostructure, we controlled the SiO2 moth-eye structure with various diameters and heights and a MgF2 single layer with varying thicknesses by sequentially performing nanosphere lithography, reactive ion etching (RIE), and electron-beam (e-beam) evaporation. Optimization of the developed AR nanostructure, which has a 100-nm-thick MgF2 film coated onto the SiO2 moth-eye-like nanostructure (diameter 165 nm and height 400 nm), minimizes the reflection loss throughout the visible range. As a result, the short-circuit current density (JSC) of the newly AR-coated PSC increases by 11.80% while the open-circuit voltage (VOC) remains nearly constant. Therefore, the power conversion efficiency (PCE) of the newly developed AR-decorated PSC increases by 12.50%, from 18.21% for a control sample to 20.48% for the optimum AR-coated sample. These results indicate that newly developed MgF2/SiO2 AR nanostructure can provide an advanced platform technology that reduces the Fresnel loss and therefore increases the possibility of the commercialization of glass-based PSCs.