R&D solar window prototypes (2014−2016) of various transparent solar glazing configurations of glass dimensions 500 mm × 500 mm. (a) Solar window with internal thin-film coated spectrally selective light deflectors using edge-attached PV modules only; (b, c) framed solar window prototypes using a combination of edge-attached and backside-perimeter PV modules, with an epoxy resin-based planar interlayer (b), or with added internally-structured transparent spectrally selective components (c). The images were reproduced from https://www.nature.com/articles/srep31831.