Y₂O₃ is a common host lattice for rare-earth activators such as Eu⁺³ in red phosphors, where it supports stable and efficient light emission.¹ Y₂O₃ is a key ingredient in yttria-stabilized zirconia (YSZ), the electrolyte used in solid oxide fuel cells due to its ability to enable oxygen ion conduction.² In the semiconductor industry, Y₂O₃ is used as a protective coating material in thin film form due to its low chemical reactivity and resistance in aggressive process environments.³ Y₂O₃ is additionally used to produce transparent yttria ceramics for infrared windows and domes, where optical transmission and durability are required.⁴ Beyond these uses, Y₂O₃ powders are added to oxide ceramic systems as sintering and microstructure control additives, influencing densification and grain growth during firing.