Effect of fluorescein concentration on morphological, structural, and photoluminescence properties of glass fibers coated with organic-inorganic hybrid films via sol-gel

In the realm of fiber surface functionalization, the sol-gel method is a prominent technique. This study aims to demonstrate its effectiveness in depositing fluorescent organic-inorganic hybrid coatings on glass fiber substrates with micron-scale diameter. The coatings were synthesized using chloropropyltriethoxysilane (CPTS) as a Si-precursor and fluorescein (FL) as the fluorescent fluorophore, with varying concentrations of FL in the hybrid sol (0.1–0.2%). SEM, AFM, and FTIR analyses confirmed the deposition of the coatings and structural modifications. Photoluminescence (PL) properties were investigated, showing yellowish-green emission. The fluorescence intensity of PL spectra increased with FL concentration, with maximum quantum yields at 0.2% FL. Samples coated with this concentration were then exposed to UV-visible irradiation at different exposure times to study the influence of photoaging on their structural and photoluminescence properties. This study successfully demonstrates the deposition of the fluorescent organic-inorganic hybrid coatings on the glass fibers surface using the sol-gel method, resulting in notable structural modifications and enhanced photoluminescence properties. Additionally, the integration of new molecules into this hybrid sol on glass fiber surfaces can offer the possibility of developing novel or improved properties that can be applied in various fields.