Tuning the Photoluminescence of Eu3+-Doped PVA/PVP Polymer Films: A Study of Red Emission Characteristics

This study aims to develop a sustainable blend of polymer films made from polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP), doped with varying concentrations of Eu³⁺ ions (0.1, 0.2, 0.3, 0.4, and 0.5 wt%), to explore their structural, optical, and photoluminescence (PL) properties for potential applications in lasers and display devices. The films were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV–visible-NIR spectroscopy, and PL. The XRD patterns revealed a reduction in the semicrystalline structure with the introduction of Eu³⁺ ions, indicating a disruption of the polymer matrix. FT-IR analysis revealed the formation of a distinct band between PVA/PVP and Eu³⁺, confirming the successful ion doping. UV–Vis–NIR analysis provided insight into optical constants, such as the absorption coefficient, indirect energy gap, and refractive index. PL studies showed red fluorescence at 615 nm, corresponding to the ⁵D₀ → ⁷F₂ transition of the Eu³⁺ ions. Additionally, the emission decay time slightly decreases with increasing Eu³⁺ concentration. The optimal doping concentration of 0.3 wt% Eu³⁺ ions in the PVA/PVP blend polymer films provides enhanced red fluorescence and is suitable for the development of laser and display applications.