Thermochemical and luminescent properties of RbVO3, CsVO3, and Rb0.5Cs0.5VO3

Abstract

RbVO3, CsVO3, and Rb0.5Cs0.5VO3 have been synthesized by the Pechini process. The vanadates have an orthorhombic structure (sp. gr. Pbcm), melt congruently in the range 650–530°C, and undergo a reversible phase transition in the range 520–340°C. We have determined the onset temperatures and end points of the transformations at a temperature scan rate of 3°C/min and their enthalpies, and measured the photo-, roentgeno-, and cathodoluminescence and diffuse reflectance spectra of the vanadates. The luminescence spectra each are well fitted with three pseudo-Voigt functions. CsVO3 has the highest integrated emission intensity. The emission intensity of the Rb0.5Cs0.5VO3 solid solution is lower than that of the simple vanadates because of the optical absorption around its intrinsic luminescence band. This may be due to the presence of stable vacancy-type structural defects in Rb0.5Cs0.5VO3.