Enhanced luminescence, photocatalytic and antibacterial performance of Ag+/Eu3+ co-doped MgO nanophosphors

Abstract

MgO, Ag-doped MgO, and Ag+/Eu3+ co-doped MgO nanophosphors were synthesized by a co-precipitation method and systematically investigated for their structural, optical, antibacterial, and photocatalytic degrada tion properties. XRD confirmed the cubic MgO phase along with additional Eu2O3 and metallic Ag phases in codoped samples, while SEM revealed a transition from irregular morphologies to spheroidized and layered agglomerated structures. Photoluminescence measurements showed strong red emission at 617 nm with maximum intensity at 2 wt% Eu3+, followed by concentration quenching. Judd-Ofelt analysis revealed dominant electric-dipole transitions and low-symmetry Eu–O environments, confirming enhanced radiative probability and strong red emission, consistent with high color purity above 90 %, correlated color temperature in the warm light range (1746–2346 K), and excellent thermal stability with 83 % emission retention at 420 K. Antibacterial tests demonstrated selective inhibition of Escherichia coli but no activity against Staphylococcus aureus, with Ag enhancing and Eu3+ modulating the response. Photocatalytic degradation of crystal violet reached 83–84 % in doped samples compared to 75 % for pure MgO, with apparent pseudo-first-order rate constants more than twice that of undoped MgO, attributed to improved charge separation, where the synergistic roles of Ag+ (electron trapping) and Eu3+ (energy transfer) further promote reactive oxygen species generation and catalytic efficiency. These results establish Ag+/Eu3+ co-doped MgO as a multifunctional material with promising applications in lighting, environmental remediation, and antibacterial systems.