Towards the Realization of Smart Windows for Joint Solar Energy Harvesting and Visible Light Communication

The transition to renewable energies and green, pervasive communications is crucial a crucial challenge for the forthcoming years. In this scenario, Luminescent Solar Concentrators (LSCs) recently offered a two-fold opportunity, combining photovoltaic and green Optical Wireless Communication (OWC) capabilities. Unlike conventional solar panels, LSCs enable transparent and coloured glazing that integrates seamlessly into modern buildings, where Building Integrated Photovoltaics (BIPV) plays a key role, particularly in urban areas, by also utilizing vertical facades for energy conversion [1]. On the other side, LSC have also recently proven as efficient, large-bandwidth (BW) and large Field of View (FoV) receivers for OWC and Visible Light Communications (VLC), with minimal sensitivity to angular misalignment [2], [3]. In both cases, the capability to realize large-area LSC panels is a crucial aspect, but the possibility of jointly exploit energy harvesting and VLC capabilities in large-area LSC has remained relatively unexplored so far. To fill this gap, we test a (0.4xO.4) m² Quantum Dot-based LSC panel, employed in certified solar-harvesting window [4], as a large-area receiver (RX) in a realistic indoor VLC setup, exploiting a high-power, commercial white LED source as data transmitter (TX). To this scope, the LSC slab is equipped with a custom-build amplified photodiode, collecting the fluorescence light which is waveguided towards the thin edges by total internal reflection. The quantum dots show efficient absorption of the blue component of the white LED spectrum, with a tailored emission spectrum yielding a large Stokes shift. We fully characterize the intrinsic properties such as BW, FoV and collection efficiency and, for the first time, we measure the VLC performances of our receiver as a function of the distance from the white LED TX, attaining VLC link distances up to 2 m 0.5 Mb/s (Figure 1). Our work paves the way towards the integration of large-area, hybrid harvesting and optical communication elements in future smart, green buildings.