Unveiling Enhanced UV ‐Shielding and Photoluminescence Behavior in Co 2 SnO 4 @ GO Nanojunction‐Reinforced PVA Nanocomposites

ABSTRACT Creating polymer nanocomposites with tunable optical features is crucial for UV shielding and optoelectronic uses. Herein, a hydrothermal method was employed to synthesize Co 2 SnO 4 nanoparticles, which were then integrated into polyvinyl alcohol (PVA) at different concentrations (0.0, 0.25, 0.5, 1.0, 1.5, and 2.0 wt%) via the solution casting technique. The structural, morphological, and optical characteristics of these PVA/Co 2 SnO 4 nanocomposites were comprehensively analyzed. Spectroscopic Techniques such as X‐ray diffraction (XRD), Fourier‐transform infrared spectroscopy (FTIR), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy‐dispersive X‐ray spectroscopy (EDX) were utilized for detailed characterization. Increasing Co 2 SnO 4 content shifted the surface from hydrophilic to hydrophobic behavior, improving moisture resistance and stability. Optical assessments showed strong absorption in the UV‐C range (250–300 nm), indicating excellent UV blocking. The optical band gap decreased from 4.78 to 4.04 eV with more filler showing direct energy band gap, along with increases in refractive index, extinction coefficient, Urbach energy, and optical conductivity, reflecting enhanced electronic transitions and charge transfer. Photoluminescence measurements showed a broad emission at 491 nm under UV excitation, with a notable Stokes shift, confirming effective UV–visible photonic conversion. Overall, the PVA/Co 2 SnO 4 nanocomposites, in the form of flexible thin films, exhibit tunable surface wettability, strong UV‐shielding capability, and enhanced optical properties. These characteristics enable their use as protective coatings and functional layers in UV‐filtering devices, flexible optoelectronics components, and photonic applications.