Visibly transparent solar harvesting surfaces provide an exciting new approach to harvesting solar energy around buildings and mobile electronics, effectively improving their energy utilization efficiency and autonomy while maintaining the aesthetics of the surfaces underneath. Transparent luminescent solar concentrators (TLSC), a key branch of transparent photovoltaic (TPV) technologies, selectively harvest the ultraviolet (UV) and near-infrared (NIR) portion of the incident solar irradiance, and optically transport the solar energy conversion to edge-mounted photovoltaic cells by waveguided photoluminescence. Due to the absence of electrodes, busbars, and collection grids over the solar harvesting area, the device structural simplicity enables these devices to achieve the highest levels of visible transparency and aesthetic quality. In the first part of this work, the theoretical efficiency limits of TLSCs are derived and practical considerations are outlined to approach these limits. In deriving these limits, key material and engineering challenges are identified to fully optimize TLSCs. Guided by this simulation work as a roadmap, three classes of fluorescent organic molecules (cyanine dyes, non-fullerene acceptors and BODIPYs) are designed, synthesized, and modified as luminophores for NIR selective-harvesting TLSC to improve the corresponding photoluminescence quantum yields, enhance the NIR spectral coverage, and suppress the reabsorption losses. The power conversion efficiency (PCE) of the corresponding NIR TLSCs have been significantly improved from 0.4% to 1.5%. To maximize the light harvesting in the invisible portion of the solar spectrum for higher PCEs, massive-downshifting nanoclusters (NC) with surface ligand modification were synthesized and combined with organic molecules into a dual-band TLSC system as UV and NIR selective harvesting luminophores, respectively. The resulting TLSC exhibits a record PCE over 3.0% with high visible transparency and is the first demonstration of this type of device which can effectively harvest both UV and NIR ranges selectively. Additionally, a practical method to seamlessly integrate these TLSCs onto arbitrary surfaces is developed to expand future deployment. Finally, standard protocols for assessing, characterizing, and reporting both the photovoltaic performance and aesthetic quality of TPVs and LSCs are also described. Collectively, these efforts highlight the promising potential of the TLSC technology for widespread adoption, effectively supplying the ever-growing energy demand on-site.
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