Template-free synthesis and photoluminescent properties of Sr2YF7:Eu3+ hollow polyhedrons-assembled hierarchical microspheres

Abstract A simple one-step hydrothermal strategy has been developed to fabricate Sr 2 YF 7 hierarchical microspheres employing NH 4 BF 4 as fluoride source. The crystalline phase and morphologies of the products were characterized by XRD, TEM and SEM. The XRD results showed that the as-prepared samples were tetragonal phased Sr 2 YF 7 with high crystallinity. SEM and TEM observation indicated that the as-synthesized hierarchical microspheres with average size of about 2 μm were assembled by hollow polyhedrons. N 2 adsorption–desorption measurements revealed that the BET specific surface area of the typical Sr 2 YF 7 hierarchical microspheres is up to 111.4 m 2 /g. The size and morphology of the products could be effectively controlled by adjusting the reaction times. Furthermore, the photoluminescence of hierarchical Sr 2 YF 7 :Eu 3+ microspheres and hollow polyhedrons were measured, the result showed that PL intensity and decay time were sensitive to the morphology of the product.