Figure 4

(a) Excitation spectra of YVO₄:Dy³⁺ 1 at.% nanopowders calcinated at different temperatures (λ_em = 573 nm). Emission spectra of YVO₄:Dy³⁺ 1 at.% nanopowders calcinated at different temperatures upon (b) λ_ex = 310 nm and (c) λ_ex = 365 nm excitation. The asterisk indicates the second order of excitation wavelength.