Diffuse Solar Micro‐Concentrators Using Dielectric Total Internal Reflection with Tunable Side and Top Profiles

Abstract

Photovoltaics (PV) is one of the most promising renewable energy technologies thanks to the ubiquitous access to solar radiation around the globe, as well as the development of multijunction PV that has increased power conversion efficiency (PCE) above the single junction limits in the past half century. [1,2] To fully realize the power production potential of PV, solar cells with higher PCEs and deployment in greater areas are required. Although the costs of silicon solar cells have been dramatically reduced in recent years, their application potential in new areas such as buildingintegrated PV, mobile power, and transportation is limited since standard silicon panels are simply too bulky, heavy, rigid, and inefficient for these applications. Multijunction solar cell technologies based on III-V semiconductors with the highest PCEs still suffer from large unit costs due to expensive materials and complicated fabrication processes, and are therefore used almost exclusively in space applications or small installations that are impractical for large-scale terrestrial power production. [3][4][5] Concentrator photovoltaics (CPV) systems have long been considered a potential solution to such difficulties. [6] Implementing optical concentrators allows for cost-efficient harvesting of solar radiation from a much larger area than that of the PV device, since it replaces expensive semiconductor photoelectronic materials with less expensive materials for the concentrator optics. [7] Moreover, it is well known that solar cells made from high-mobility crystalline materials can benefit from higher incident radiation intensities to produce higher PCEs at increased open-circuit voltages (V oc ), making concentrators almost a necessary component for large-scale commercialization and terrestrial deployment of III-V high-PCE multijunction solar cells. [8][9][10] Building-integrated photovoltaics (BIPV) is a popular nextgeneration implementation of PV systems with unique requirements. [11] Direct integration of PV into the building envelope enables the utilization of a large portion of existing building surface area to generate power, and reduces costs related to electricity transportation and distribution. [12] The utilization of BIPV systems as building envelope materials has the potential to not only enable cost savings, but also become a source of income for a building. Despite the presence of many implementation