فهرست نشریات علمی دسترسی آزاد ایران

This study investigates the optical properties of polyvinylpyrrolidone (PVP) nano-thin films doped with barium chloride (BaCl₂) at concentrations of 3 %, 5 %, 7 %, 9 %, and 10 % in UV-Vis spectral region. Different characterisation techniques were used for material analysis. The research examines concentration-dependent effects on optical absorption characteristics and electronic band structure through UV-Vis spectroscopy and Tauc plot analysis. Results demonstrate systematic decrease in optical bandgap energy with increasing BaCl₂ concentration, consistent with established semiconductor doping phenomena. Absorption coefficient measurements revealed distinct optical regimes across the concentration range, reaching maximum values of 5.1-5.2 × 10⁷ (v/cm)² at 6.25 eV for optimally doped samples. Findings revealed that 3 % sample exhibited baseline optical characteristics, while 5 % sample showed anomalous behavior attributed to critical concentration effects. The 7 % sample concentration demonstrated transitional behavior, and 9 % sample achieved remarkably stable properties with homogeneous dopant distribution, representing optimal balance between electronic modification and crystalline quality. The 10 % sample approached solid solubility limits, showing convergence with other optimal concentrations. Mechanisms include impurity band formation, bandgap narrowing due to many-body interactions, and development of degenerate semiconductor behavior at highest concentrations. These comprehensive findings demonstrate significant modification of PVP optical properties through systematic BaCl₂ doping, creating new opportunities for advanced functional materials in photodetectors, photovoltaics, and optical devices with tailored spectral properties.