Pure monoclinic La1-xEuxPO4 micro-/nano-structures: Fast synthesis, shape evolution and optical properties

Rare-earth-doped LaPO4 crystals have been attracting considerable interest. In this work, we reported the fast syntheses of LaPO4 and Eu-doped LaPO4 crystals via a simple oil-bath route, employing La(NO3)(3) and KH2PO4 as the original reactants, Eu2O3 as the dopant. The reaction was carried out in ethylene glycol system at 120 degrees C for 30 min without any assistance of surfactants or templates. X-ray powder diffraction analyses showed that pure monoclinic LaPO4 form was obtained in the system without Eu3+ ions, and the above phase was not changed after integrating Eu3+ ions into LaPO4 matrix. However, electron microscopy observations discovered that the integration of Eu3+ ions into LaPO4 matrix obviously changed the morphology and size of the final La1-xEuxPO4 crystals. With the increase in Eu3+ amount from 0 to 0.35, the shape of the final product varied from homogeneous egg-like nanospheroids, to irregular grains with microscales, and to homogeneous microspheroids. Also, the Eu3+ ion content in La1-xEuxPO4 markedly affected the photoluminescence properties of the final product. When x = 0.2, the product exhibited the strongest PL emission. (C) 2014 Elsevier Inc. All rights reserved.