LaPO4:Eu microstructures constructed by nanorods with triangular pores in the ends: a simple mixed-solvothermal synthesis, growth mechanism and optical property

Abstract

Flowerlike LaPO₄:Eu microstructures built up of nanorods with triangular pores in the ends have been successfully synthesized by a simple water–ethyleneglycol (EG) mixed solvothermal route in the presence of appropriate amounts of concentrated HNO₃ and Eu₂O₃. Lanthanum nitrate (La(NO₃)₃) and monopotassium phosphate (KH₂PO₄) were used as the La³⁺ ion and the PO₄³⁻ ion source, respectively. X-Ray powder diffraction (XRD) analyses showed that the product was a mixture of hexagonal and monoclinic phases and could be converted to pure monoclinic phase after calcining at 400 °C for 2 h. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy observations exhibited that the morphology of the product did not change before and after calcination. The optical properties and the thermal stability of the flowerlike LaPO₄:Eu microstructures were studied. Experiments showed that the presence of appropriate amounts of concentrated HNO₃ had a crucial role in the formation of flowerlike LaPO₄:Eu microstructures. Based on a time-dependent shape evolution experiment, a possible growth mechanism of the flowerlike LaPO₄:Eu microstructures was proposed.