Synthesis and Luminescent Properties of CeO2:Pr4+, Eu3+ Red Pigments

Coloring and photoluminescent properties of Pr4+- and Eu3+-codoped CeO2 were investigated to produce red-colored and red-luminescent phosphors. CeO2:Pr4+,Eu3+ particles were attempted to be synthesized by employing two kinds of methods; a conventional solid-state reaction method and a newly developed precipitation method. In case of the solid-state reaction, it was found that red emissions from the Eu3+-doped CeO2 sample were enhanced by codoping Pr4+ at a extremely low concentration. The codoped Pr4+ ions also generated red coloring of the sample. However, the light absorption due to the Pr4+ ions became stronger at the higher doping level, thereby quenching the red emissions from the Eu3+ ions. In the precipitation method using aqueous Pr(CH3COO)(3)center dot 2H(2)O solutions containing urea, luminescence quenching of products could be suppressed even at the higher Pr4+-doping level, leading to the development of red-colored phosphor materials. This achievement was due to the inhomogeneous distribution of the coloring Pr4+ ions and the emitting Eu3+ ions in the CeO2 particles. (C) 2012 The Electrochemical Society. All rights reserved.