Enhancing the efficiency of luminescent solar concentrators via soft colloidal lithography negative templating

Building-integrated photovoltaics (BIPV) offers a sustainable pathway by seamlessly incorporating PV cells into architectural elements like façades and windows. In this study, we investigate the potential of luminescent down-shifting solar concentrators in combination with a nanophotonic light-trapping scheme to improve the optical-guiding capabilities and thereby enhance the energy conversion efficiency. We propose a novel cost-effective method to fabricate the photonic structures via soft colloidal lithography negative templating of thin films of TiO2 nanoparticles, successfully scaling the production to 11x11 cm2 glass windows. Through simulations and optical-electrical characterization, we demonstrate substantial improvements in energy harvesting for different angles of solar irradiation. We found increases in power output ranging from 57% for angles of incidence below 45° to above 100% for 60° thanks to the nanostructured TiO2 nanoparticles coatings added to a bottom down-shifting layer. This shows that such integrated approach can enhance both the efficiency and aesthetic appeal of solar solutions in urban environments, advancing the design of energy-efficient, sustainable buildings. Our methodology ensures consistent solar energy capture all year-round, for the relevant range of sunlight incidence angles, while preserving the transparency and multifunctionality of building elements.