Kinetic Control over YVO₄:Eu³⁺ Nanoparticles for Tailored Structure and Luminescence Properties

A series of nanocrystals Y 1- x Eu x VO 4 ( x = 0–0.1) were prepared by isothermal and isochronal hydrothermal reactions using citric acid as the capping agent. All nanocrystals were controlled to show particle sizes ranging from 7 to 36 nm, which gives rise to the grain growth kinetics in terms of an equation, D 5 = 6.71 5 + 2.82 × 10 10 t exp(−51.50 /RT ) for x = 0.05. Structural refinements of these nanocrystals demonstrate that as particle size reduces, there appeared an abnormal lattice expansion. The expansion rate is strikingly dependent on the substitution content of Eu 3+ in Y 1- x Eu x VO 4 . Namely, higher Eu 3+ content led to a larger lattice expansion. With these structural changes, nanocrystals of Y 0.90 Eu 0.10 VO 4 were found to show the maximum luminescence performance as represented by a long lifetime of 1.33 ms. The findings reported in this work are fundamentally important, which might be extended to other doped phosphors with controlled grain growth kinetics for advanced properties.