Synthesis and luminescent properties of LaPO4:Eu3+ microspheres

Highlights: • LaPO4:Eu3+ microspheres with a monoclinic phase were synthesized. • CTAB plays an important role in the formation of LaPO4:Eu3+ microspheres. • The LaPO4:Eu3+ microspheres have an enhanced emission intensity. -- Abstract: LaPO4:Eu3+ microspheres were synthesized, using LaCl3, EuCl3 and (NH4)2HPO4 as starting materials. The morphology, formation mechanism, and luminescent property of samples were systemically studied. X-ray diffraction (XRD) and infrared spectroscopy (IR) show that LaPO4:Eu3+ microspheres have a pure monoclinic phase. Cetyltrimethyl ammonium bromide (CTAB) usually forms spherical micelles above a critical micelle concentration, which plays an important role in the formation of LaPO4:Eu3+ microspheres. The excitation spectrum of LaPO4:Eu3+ microspheres consists of several sharp lines due to the direct excitation of the Eu3+ cations from the ground state to higher levels of the 4f-manifold. The emission intensity of microspheres is higher than irregular particles because of the lowlier surface area. The lifetimes of Eu3+ ions in the LaPO4:Eu3+ microspheres are determined to be 2.41 ms