Magnesium Silicate Phosphors: A Comprehensive Review of Mg2SiO4 (Forsterite) and MgSiO3 (Enstatite) Hosts

Forsterite (Mg2SiO4) and enstatite (MgSiO3) are magnesium-silicate host materials that have attracted considerable recent research interest as candidates for luminescent applications, owing to their excellent chemical and thermal stability, structural diversity, and their capacity to accommodate rare-earth ions as activators. This review provides a systematic account of preparation methods, including solid-state, sol-gel, combustion, hydrothermal, and mechanicalactivation routes, together with the photoluminescence (PL), thermoluminescence (TL), and persistent-luminescence behaviour reported for magnesium-silicate phosphors doped with rare-earth and transition-metal ions. The roles of Eu3+, Eu2+, Tb3+, Dy3+, Mn2+, and related dopants in producing photoluminescence, thermoluminescence, persistent luminescence, and other optical properties are discussed, with particular attention to trap-mediated persistent luminescence in MgSiO3:Eu2+,Dy3+,Mn2+ and Mg2SiO4:Eu2+,Dy3+ systems, as well as the photoluminescence, thermoluminescence, and dosimetric properties of rare-earth-activated Mg2SiO4. Characterisation approaches, including X-ray diffraction, steady-state and time-resolved photoluminescence, thermoluminescence and optically stimulated luminescence, electron microscopy, and defect-sensitive spectroscopies, are summarised in relation to their utility for probing phase purity, morphology, and trap structure. The review further examines the importance of defect chemistry, trap distribution, particle size, crystallinity, and synthesis conditions in determining luminescence performance, and presents a tabular literature resource summarising representative studies across both host systems. Current challenges and future opportunities are identified, including improved trap identification, nanoscale surface passivation, standardised luminescence reporting, and the development of magnesiumsilicate phosphors for persistent near-infrared emission and advanced photonic applications. Overall, Mg2SiO4 and MgSiO3 emerge as versatile, chemically robust platforms for activator- and defect-engineered luminescent materials with continuing relevance to solid-state lighting, radiation dosimetry, and persistent-luminescence technologies.