Synthesis of Er-Yb co-doped MgNb₂O6 ceramics and the exploration of their up-conversion photoluminescence and photocatalytic properties

Author(s)

Yakubu, Shedrach ; Meirelles, Mariana Rodrigues ; Kolawole, Funsho Olaitan ; Gonsalves, Maraisa ; Eiras, J. A. ; Lente, M. H.

• Document type: Journal article
• Source: Optical Materials; v. 163, p. 13-pg., 2025-06-01.

Abstract

Rare earth (RE) doped ceramic materials are now known to offer considerable promise as phosphors, providing avenues for a wide range of applications in the photon domain when synthesized with appropriate compositions and crystal structures. Furthermore, because of the charge carriers (electron-hole pair) that these phosphors contain, they have also the potential for photoluminescence and photocatalysis. This research explores the solidstate synthesis of RE-doped MgNb2O6 and the characterization of their upconversion photoluminescence and photocatalytic properties. Three different compositions of the columbite, MgNb2O6, MgNb2O6-Er, and MgNb2O6-Er-Yb were synthesized via solid-state reaction methods. Their crystallographic structures were confirmed to be orthorhombic for all the three compositions, with slight expansion in the RE-doped compositions' bulk volume. Their measured band gap energy (Eg) were 3.93, 4.03, and 4.03 eV, respectively. The room temperature up-conversion photoluminescence spectra of the as-sintered RE-doped ceramic bodies showed two emissions near 543 nm and 674 nm, which corresponded to the transitions of Er3+ ions from 2H11/2 to 4I15/2 and 4F9/2 to 4I15/2, respectively. As proposed by theoretical models, it was confirmed that the photoluminescence intensity is proportional to the nth power of the excitation intensity. This up-conversion photoluminescence was observed as an enhancement in the fluorescent intensity of the Er-Yb co-doped samples, possibly due to the charge transfer process between Yb3+ and Er3+ ions. The photocatalysis under UV light and adsorption studies for the decolorization of Victoria blue dye were investigated with about 50 % dye removal in the evaluated conditions. The VB dye removal indicated that the RE-doped MgNb2O6 Columbite is potentially applicable in environmental remediation. (AU)

• FAPESP's process: 24/06119-4 - Growth of multiferroic single crystals and characterization of their optical properties for piezophotonic applications
• Grantee: Yakubu Shedrach
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 17/13769-1 - Multiferroic and ferroelectric materials for energy converters: synthesis, properties, phenomenology and applications
• Grantee: José Antonio Eiras
• Support Opportunities: Research Projects - Thematic Grants