Luminescence spectra of Eu(III/II)-doped LaAlO3 powders prepared by a solid-state reaction of Eu(III)-doped LaCO3OH and Al2O3

Abstract

Lanthanum aluminate (LaAlO3) powder was prepared by a solid-state reaction of lanthanum(III) hydroxycarbonate (LaCO3OH) and nanosized δ-alumina (δ-Al2O3) powders at elevated temperatures. The conversion of LaCO3OH into LaAlO3 was monitored by powder X-ray diffraction and 27Al magic-angle spinning nuclear magnetic resonance spectroscopy. The latter tool was useful for the detection of unreacted Al2O3 in final products. The formation temperature of LaAlO3 was reduced using metal fluorides as an additive. The luminescence spectra of Eu(III)-doped LaAlO3 (LaAlO3:Eu3+) powders obtained by calcination of a mixture of LaCO3OH:Eu3+ and nanosized δ-Al2O3 were compared with those of LaAlO3:Eu3+ powders obtained by other synthesis methods. The LaCO3OH:Eu3+–Al2O3 reaction system was preferable to the La2O3–Eu2O3–Al2O3 reaction system because LaAlO3:Eu3+/2+ powders exhibited stronger emission peaks.