Lanthanide-Doped REVO4 (RE = Y, Gd, Lu, La) Phosphors: From Synthesis to Sensing Applications

Rare-earth elements including the fifteen lanthanides, from lanthanum (La) to lutetium (Lu), together with scandium (Sc) and yttrium (Y), can act either as matrix cations or as active luminescent centers when incorporated into host lattices. Owing to their relatively large ionic radii, high coordination numbers, and structural stability, ions such as La, Lu, Sc, Y, and gadolinium (Gd) typically serve as matrix cations in rare-earth vanadate (REVO4)-based phosphors, while other trivalent lanthanide (Ln3+) ions act as active luminescent centers. These REVO4 phosphors have proved to be good host lattices for optically active Ln3+ ions giving strong luminescence assigned to absorption of the vanadate (VO43−) groups, and the efficient energy transfer between host lattice and Ln3+ ions. The unique electronic configuration of Ln3+ ions, particularly their unpaired 4f electrons, makes them ideal for applications in luminescence, magnetism, electronic and magnetic relaxation, and catalysis. Due to their complementary luminescent characteristics, Ln3+-doped REVO4 phosphors have attracted significant attention in recent years. Their unique optical properties make them highly valuable across a broad spectrum of applications. This paper provides a comprehensive review of the state of the art in Ln3+ (Eu3+, Sm3+, Tm3+, Er3+, Ho3+, Tb3+, Nd3+, and Yb3+)-doped REVO4 (RE = Y, Gd, Lu, La) phosphors. It examines current synthesis approaches, alongside the development of advanced strategies, and explores structural characteristics, innovative designs, and luminescent behavior, including both downconversion and upconversion processes and sensing applications, of the Ln3+-doped REVO4 phosphors.