Organic-Inorganic Hybrid One-Dimensional Photonic Crystals with Blue and NIR Dual Bandgaps for Light Protection

Planar 1D photonic crystals (1DPhCs), owing to their photonic bandgaps (PBGs) formed by unique structural interference, are widely utilized in light protection applications. Multifunctional coatings that integrate various light management functions are highly desired. In this study, we present the fabrication of dual-PBG 1DPhCs with high reflectance in both the blue and near-infrared (NIR) regions. The 1DPhCs were constructed through the alternating stacking of hollow SiO₂ (HS) nanoparticles hybridized with poly(vinyl alcohol) (PVA), referred to as PHS, and TiO₂ layers. The 1DPhC with 7 bilayers demonstrated remarkable reflectance of 98.2% and 93.4% in the blue and NIR spectra, respectively, with shielding efficiencies of 93.9% and 85.6%. Compared to bare PC, the temperature was observed to be 10.6 °C lower, achieving a thermal insulation efficiency of 44.8% in the 900 nm near-infrared range. Additionally, spectral fitting using the transfer matrix method (TMM) and optimization of process parameters, including PHS concentration and spin-coating speed, enabled the fabrication of 1DPhCs with tunable optical thickness ratios. The fabricated films demonstrated a smooth surface morphology with flat and uniform interfaces, as well as excellent environmental stability. These features make the 1DPhCs highly promising for applications in light protection and thermal management. This study provides a novel approach for the development of dual-PBG 1DPhCs with enhanced protective capabilities.