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

Abstract

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.