Design of broadband anti-reflection coatings for III-V/Si tandem solar modules in vehicle-integrated photovoltaic application

Anti-reflection coatings (ARCs) are an essential component of photovoltaic modules, crucial for minimizing optical reflection losses and maximizing power output. This study focuses on the optimized design and experimental validation of ARCs for a triple-junction module configuration, developed through the hybridization of III-V multi-junction and crystalline silicon (c-Si) cells for potential automotive integration. A nanoporous silica film was fabricated on the encapsulating glass surface as an ARC by spray-coating and thermal treatment method. Experimental data reveal that this film effectively reduced reflectance across a broader spectral range and to a lower magnitude compared to conventional MgF₂ single-layer ARCs typically used for glass substrates. Additionally, a pseudo-three-layer ARC utilizing dielectric multilayers was designed and prototyped on the surface of a silicone-encapsulated InGaP/GaAs dual-junction cell. Evaluation of this structure indicated that, in contrast to a two-layer ARC, it broadened the effective spectral bandwidth, consequently increasing the incident light flux upon the underlying Si cell without compromising the anti-reflective performance of the upper dual-junction cell.