This paper presents a novel Fresnel lens capable to significantly reduce chromatic aberration in solar applications. The optical performance of this achromatic lens has been analyzed through ray-tracing simulations, showing a concentration factor three times higher than that attained by a classic Silicone On Glass (SOG) Fresnel lens while maintaining the same acceptance angle. This should avoid the need for a secondary optical element, reducing the cost associated with its manufacturing and assembly and increasing the module reliability. The achromatic lens is made of inexpensive plastic and elastomer which allows a highly scalable and cost-competitive manufacturing process similar to the one currently used for the fabrication of SOG Fresnel lenses.

A tracking-integrated hybrid micro-concentrator module is presented that can harvest direct, diffuse, and albedo irradiance components. It uses biconvex 180× lens arrays to concentrate direct light on high-efficiency III-V solar cells (29% module efficiency has been demonstrated outdoors on direct sunlight at Concentrator Standard Test Conditions) and a planar micro-tracking mechanism to allow installation in static frames. Two architectures have been developed to harvest diffuse irradiance: (1) a hybrid architecture where the backplane is covered with monofacial or bifacial Si cells; (2) a translucent architecture where diffuse light is transmitted through the module for dual-land-use applications, such as agrivoltaics. Simulations show that the hybrid architecture provides an excess of yearly energy production compared to 20% efficiency flat-plate photovoltaic (PV) module in all locations studied, including those with a low direct normal irradiance (DNI) content, and up to 38% advantage in high-DNI locations. The use of bifacial heterojunction and interdigitated back-contact Si cells has been explored for the glass-Si-glass backplane laminate to harvest albedo light. Bifacial gains modeled can boost energy yield by about 30% in the best scenario. We discuss the perspectives of the translucent modules for dual-land-use applications as well, such as integration in greenhouses for agriculture-integrated PV (agrivoltaics). This architecture can provide up to 47% excess electricity compared to a spaced reference Si array that transmits the same amount of solar

Roll-to-roll nanoimprint lithography (R2R-NIL) is an enabling technology for the low-cost mass production of high-quality micro- and nano-sized optical elements. Particularly, the fabrication of Fresnel lenses using R2R-NIL is a promising approach to produce optical arrays for micro-concentrator photovoltaic modules. This work investigates the application of a continuous R2R imprinting process based on ultraviolet curing of transparent photopolymer resins (UV-NIL) to fabricate high-efficiency and low-cost Fresnel lenses. The morphological attributes and the related optical performance of the lenses fabricated using roll-to-roll UV-NIL on flexible PET sheets yielded optical efficiency values up to ∼ 69% at a concentration ratio of 178X, whereas a value of ∼ 77% was obtained for the UV-NIL batch processed on a flat rigid substrate. Further improvement of the optical efficiency has been achieved by adding moth-eye inspired antireflective (AR) features on the side opposite to the Fresnel motifs via a double-sided R2R UV-NIL process. The process developed paves the way for cost-effective mass production of high-efficiency Fresnel lenses for micro-concentrator photovoltaics.

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In this paper we present a novel manufacturing method to produce achromatic Fresnel lenses for photovoltaic application. These achromatic lenses are capable of reaching a concentration factor three times higher than that attained by a conventional Silicone-on-Glass (SOG) Fresnel lens. The manufacturing method presented to fabricate the achromatic lens, which we refer to as Achromatic Doublet on Glass (ADG) Fresnel lens, is simple, cost-effective and highly scalable. A comprehensive ray-tracing analysis and its comparison with experimental results is presented in this work.