Engineering the optical, and dielectric properties of (PVA: PVP)/BaSnO3 polymer nanocomposites as promising films for optoelectronics and energy storage applications

This work is devoted to optimizing the optical and dielectric parameters of polyvinyl alcohol (PVA): polyvinyl pyrrolidone (PVP) (1:1) polymer nanocomposites by controlling barium stannate contents (BaSnO3) aspiring to engage it into flexible optoelectronics and thermally stable capacitors. Herein, high purity BaSnO3 was synthesized by solid-state route and loaded with different ratios (5-20 wt%) into PVA/PVP blend to form films by solution casting method. Further, the degree of crystallinity (X-c) was highly increased upon increasing the filler contents (BaSnO3), as confirmed by X-ray diffractometer measurement. The surface morphology pictured by a field emission scanning electron microscope revealed the variation of the surface from smooth to rough surface upon insertion of BaSnO3. The thermodynamic parameters including enthalpy (Delta H), entropy (Delta S), and Gibb's free energy (Delta G) were extracted from TGA measurements and studied in detail. The optical characteristics of plain PVA/PVP and polymer nanocomposite films are explored by UV-Vis-NIR spectrophotometer. The presence of charge-transfer complexes within the polymer nanocomposites was certified via shifting of band gap energy from 5.02 to 4.33 eV and variation of band tailing energy (E-u) from 0.22 to 0.44 eV. The real and imaginary part of optical conductivity (sigma(p1), sigma(p2)) was confirmed to be enhanced with the insertion of BaSnO3. It is also found that the dielectric constant and DC current increased with the insertion of BaSnO3 content, while the dielectric loss decreases. The findings recommend these polymer nanocomposites as a good candidate for green energy applications and high-performance capacitors.