Femtosecond-laser-surface-nanostructured glass for building-integrated photovoltaics

The emerging luminescent solar concentrators (LSC) for building-integrated photovoltaics (BIPV) face challenges such as narrow conversion spectrum, material degradation, high costs, and safety concerns, while their reliance on complex fabrication processes further hinders their practical application in large-area systems. In this paper, we present a novel application of femtosecond-laser-nanostructured borosilicate glass for BIPV, offering a promising alternative to traditional LSC windows. Utilizing a scalable, one-step femtosecond laser direct writing process, we fabricate nanostructured borosilicate glass specifically designed to effectively scatter incident light toward solar cells positioned at the edges of the glass. To optimize the laser processing, we perform comprehensive characterizations using scanning electron microscopy, X-ray diffraction, Raman spectroscopy, photoluminescence spectroscopy, and spectrophotometry. The proof-of-concept system demonstrates that the glass processed at an optimized scan speed exhibits a 55-fold increase in photocurrent generation compared to unprocessed glass, highlighting its enhanced optical efficiency. Additionally, a hydrophobic coating is applied on the nanostructured glass to confer self-cleaning properties, achieving superhydrophobicity with advancing and receding contact angles of approximately 170°. This novel approach to utilizing nanostructured glass for solar concentration shows considerable promise for improving both the efficiency and practicality of building-integrated photovoltaics.