Synthesis and luminescence of La2BaZnO5 phosphors

A modified synthesis of La2BaZnO5 phosphors activated with rare earths Eu3+, Tb3+, Pr3+ and Sm3+, and ns(2) ion Bi3+ is reported. RE2BaZnO5 compounds are conventionally prepared by two step solid state reaction. In the first step, carbonates or similar precursors are intimately mixed and heated at 900 degrees C to decompose the precursors to oxides. To eliminate the unwanted phases like BaRE2O4, the resulting powders are reheated at 1100 degrees C for long time. We prepared La2BaZnO5 phosphors activated with various activators by replacing the first step by combustion synthesis. Results on photoluminescence are presented. PL results on Eu3+ and Tb3+ are in good agreement with the literature reports. PL emission from Sm3+, Pr3+ and Bi3+ had not been reported earlier. Excitation spectrum of Eu3+ is dominated by a charge transfer band around 318 nm, while for the other rare earths a band at 240 nm is always present. This is attributed to the host absorption. (C) 2011 Elsevier B.V. All rights reserved.