High-efficiency luminescent solar concentrators based on anti-fogging and frost-resisting fluorescent polymers: adding multiple functions for sustained performance

Luminescent solar concentrators (LSCs) are light-management devices able to harvest and downshift sunlight, making it available to edge-coupled photovoltaic cells for light-to-electricity conversion. When operating in real-life outdoor scenarios, LSCs can be exposed to humid/freezing environments which may yield fogging and frosting, ultimately resulting in detrimental performance decay owing to reduced photon absorption and photon trapping efficiency within the waveguide. To address this issue, the first demonstration of an antifogging/frost-resisting highly efficient thin-film LSC is presented in this work, based on a tailored semi-interpenetrating polymer network serving as the host matrix material, where the antifogging behavior is imparted by the simultaneous presence of hydrophilic and hydrophobic segments in the macromolecular structure, whereas the fluorescent response is achieved via the incorporation of a coumarin-functionalized methacrylic monomer. By judicious selection and compositional tuning of an additional luminescent guest dopant with excellent spectral match with the fluorescent host matrix, highly efficient (?98%) energy transfer is achieved. Optimized LSC devices exhibit external and internal photon efficiencies as high as 3.96% and 34.79%, respectively. In addition, persistent and reproducible antifogging/frost-resisting functionality is demonstrated during aggressive aging tests under UV-light, with preserved fluorescence emission and prolonged and sustained device efficiency.