Hollow TiO₂:Sm³⁺ spheres with enhanced photoluminescence fabricated by a facile method using polystyrene as template

Uniform hollow Sm³⁺-doped titania phosphors were prepared via a facile method using polystyrene spheres as template. After calcination at 500 C for 3 h, hollow TiO₂:Sm³⁺ spheres with outer diameters of approximately 250 nm and a shell thicknesses ranging from 50 to 70 nm were obtained. A possible formation mechanism of the evolution process of the spheres was discussed in this paper. Photoluminescence (PL) results showed that the emission intensity of the as-prepared hollow TiO₂:Sm³⁺ spheres was 2.1 times higher than that of amorphous nanoparticles (NPs). We propose that this PL enhancement is due to the unique hollow structures obtained.