Morphology-sensitive photoluminescent properties of YVO4:Ln3+ (Ln3+ = Eu3+, Sm3+, Dy3+, Tm3+) hierarchitectures

Highlights: • Flower-like YVO₄:Ln³⁺ hierarchitectures were synthesized by hydrothermal method. • The formation mechanisms of different microstructures were proposed. • The as-prepared products show morphology-sensitive photoluminescent properties. -- Abstract: Novel three-dimensional YVO₄:Ln³⁺ (Ln³⁺ = Eu³⁺, Sm³⁺, Dy³⁺, Tm³⁺) hierarchitectures were successfully fabricated on glass substrate by a simple, hydrothermal process by using disodium ethylenediaminetetraacetic acid (Na₂H₂L, where L⁴⁻ = (CH₂COO)₂N(CH₂)₂N(CH₂COO)₂⁴⁻)) as a capping agent. The shape and size of product can be tailored by controlling the reaction time and the Na₂H₂L/Y³⁺ molar ratio. As a typical morphology, YVO₄:Eu³⁺ shows a flower-like hiearchitecture, which is composed of a primary microrod trunk and a large number of secondary nanonails. The trunk is a rectangle prism with a length of 2 μm. The nanonail branch has a length of 400 nm and a diameter of 80 nm, and its cap has a diameter of 100 nm with a thickness of 20 nm. A possible formation mechanism of this flower-like hierarchical structure was proposed, and it is investigated in detail through time evolution experiments. Under UV radiation, the thin film samples were shown the emission characteristic of Eu³⁺ (⁵D₀→⁷F₂, 618 nm), Dy³⁺ (⁴F_9/2 → ⁶H_13/2, 575 nm), Sm³⁺ (⁴G_5/2 → ⁶H_7/2, 603 nm), Tm³⁺ (¹G₄→³H₆, 478 nm), and morphology-sensitive photoluminescent properties.