Large-scale synthesis and luminescence of GdPO(4) hollow microspheres

GdPO(4) hollow microspheres were synthesized by using a novel multi-step transformation synthetic route for the first time with polystyrene (PS) spheres as the template, followed by the combination of a facile homogeneous precipitation method, an ion-exchange process, and a calcination process. The XRD results indicated that the GdPO(4) hollow microspheres have a pure hexagonal phase. The SEM and TEM images confirmed that the as-obtained GdPO(4) hollow spheres have a uniform morphology with an average diameter of 2.7 μm and shell thickness of about 150 nm. The up-conversion luminescence properties as well as the emission mechanisms of the GdPO(4):Yb(3+), Ln(3+) (Ln(3+) = Tm(3+), Er(3+) and Ho(3+)) hollow microspheres were systematically investigated, which show blue (Tm(3+), (1)G(4) → (3)H(6)), green (Er(3+), (4)S(3/2), (2)H(11/2) → (4)I(15/2)), and red (Ho(3+), (5)F(5) → (5)I(8)) luminescence under 980 nm NIR excitation, providing potential applications in bioanalysis, optoelectronic and nanoscale devices, future color displays and light-emitting devices, and so on.