A novel synthetic route towards monodisperse LaOF:Ln3+ (Ln = Eu, Tb) hollow spheres with multicolor luminescence properties

Abstract

In this study, monodisperse and uniform LaOF hollow spheres were successfully synthesized through a novel facile synthetic route employing a La(OH)CO₃ sphere as a sacrificial template followed by a subsequent calcination process. The structure, morphology, formation process, and luminescence properties were well investigated using various techniques. The possible formation mechanism of evolution from the La(OH)CO₃ spheres to the LaCO₃F precursor, and to the final LaOF hollow spheres can be attributed to the Kirkendall effect and the decomposition of the LaCO₃F precursor. Under ultraviolet excitation, the LaOF:Ln³⁺ (Ln = Eu,Tb) hollow spheres show their characteristic f–f emissions and exhibit red, green emissions, respectively. Moreover, by codoping the Tb³⁺ and Eu³⁺ ions into the LaOF host and tuning their relative concentration ratio, multicolor tunable emissions are obtained due to the efficient energy transfer from Tb³⁺ to Eu³⁺ at 378 nm excitation. This material may find potential application in color display fields.