New luminescent solar concentrator windows using PMMA-InP/ZnS Nanohybrid coating films for green building applications

Abstract

Green fluorescing PMMA-InP/ZnS nanohybrid coating films were applied onto FTO glass substrates through the traditional spin coating technique for the development of luminescent solar concentrator windows. Examination using transmission electron microscopy (TEM) displayed good morphology and uniform dispersion of InP/ZnS quantum dots (QDs) in PMMA matrix, whereas X-ray diffraction (XRD) indicated the amorphous nature and good adhesion to FTO glass substrate. Investigations of the influence of varying QD concentrations on spectral photophysical characteristics were conducted using techniques such as optical absorption, transmission, fluorescence spectroscopy, and the chromaticity diagram (CIE 1931). The films exhibited good transparency in the visible spectrum, approximately 87 %, with reduced transparency in the near-infrared (NIR) region, approximately 26 %. The films have various shades of green colors closely aligned with the sensitivity of the human eye, as demonstrated by CIE 1931 chromaticity diagram. Skin depth calculations spanning the UV to NIR wavelengths (200-2400 nm) showed a marked decrease in electromagnetic wave penetration correlating with increased InP-ZnS QD concentrations. Fluorescence spectroscopy revealed the highest fluorescence intensity and quantum yield of 71 % for QDs concentration of $0.15wt\%$ coupled with outstanding photostability properties after exposure to UVA radiation (365 nm) for 72 h. This optimization effectively reduces the infiltration of detrimental solar radiation into buildings, encompassing ultraviolet and infrared wavelengths. The research outcomes are consistent with the objectives of Sustainable Development Goals SDG7 and SDG 11, in sun-drenched regions such as Saudi Arabia, as PMMA-InP/ZnS nanohybrid coating films can be tailored to meet the spectral needs of energy-efficient windows.