Publication

Abstract : Dy3+-doped BaY₂O₄ nanophosphors (NPs) were prepared using simple solution combustion (SC) technique, employing metal nitrates as oxidizing agents and plant extract as fuel. The highly exothermic redox reaction rapidly produced phase-pure, crystalline BaY₂O₄ doped with Dy3+ ions. Powder X-ray diffraction (PXRD) demonstrated the pure orthorhombic BaY₂O₄ structure (JCPDS No. 27-0044). The optical band gap energies were estimated from diffuse reflectance spectra (DRS) using the Kubelka–Munk function and were found to lie within the range of 4.14–4.58 eV. FTIR analysis confirmed molecular bending and stretching vibrations, while FESEM revealed a porous, sponge-like morphology. Transmission electron microscopy (TEM) analysis revealed an average particle size of ∼40 nm, with an interplanar spacing (d) of 0.24 nm. Photoluminescence (PL) studies, performed under 370 nm excitation, exhibited prominent emission peaks at 492 nm (4F₉/₂ → 6H₁₅/₂, blue) and 573 nm (4F₉/₂ → 6H₁₃/₂, yellow), with maximum emission intensity observed at 7 mol% of Dy3+ ion concentration. Afterwards it declines and was attributed to concentration quenching. The estimated CIE chromaticity coordinates corresponded to near-white light emission, emphasizing the potential use in solid-state lighting and LED technologies. The average correlated color temperature (CCT) was calculated to be ∼4328 K, aligning with the range appropriate for cool white light-emitting diode (wLED) applications. The photocatalytic activity of the phosphors was assessed via degradation of Malachite Green (MG) under UV irradiation. The 7 mol% Dy3+-doped sample demonstrated the highest degradation efficiency, which was ascribed to improved charge carrier separation and a higher density of reactive surface sites. It was noticed that, about ∼90.32 % dye removal taken place in 90 min. At lower dye concentration higher degradation was noticed. At neutral pH it was observed highest degradation. These results highlight the multifunctionality of BaY₂O₄:Dy3+ NPs as both an efficient luminescent material and an effective photocatalyst, positioning it as a efficient candidate for integrated optoelectronic and environmental applications.