Novel pure Ca2 ZnMoO6 composition with white-light luminescence.

Abstract

Phosphors with composition Ca2 ZnMoO6 were synthesized at temperatures of 800-1200°C using the solid-state method. Analysis of X-ray diffraction patterns of the Ca2 ZnMoO6 powders did not reveal a double perovskite structure. When the synthesis temperature was equal to or higher than 800°C, the synthesized Ca2 ZnMoO6 powders revealed a tetragonal structure (CaMoO4 ) rather than an orthorhombic structure (Ca2 ZnMoO6 ) and the cubic structure (Sr2 ZnMoO6 ) of a double perovskite. The ZnO phase was still observed at a synthesis temperature of 1200°C. The compositions of synthesized Ca2 ZnMoO6 powders differed from the prepared powder, and the Ca2 ZnMoO6 phosphors exhibited some important novel features. First, synthesized Ca2 ZnMoO6 compositions could emit light as a phosphor no activators, called Ca2 ZnMoO6 phosphors. Effect of synthesis temperature on luminescence properties of these Ca2 ZnMoO6 phosphors was readily observed, and some important novel features and properties were noted. Second, the phosphors presented only one broad characteristic emission peak in the visible light region. Third, measurement of the chromaticity diagram of the Ca2 ZnMoO6 phosphors revealed a white-light source. Through analysis, we determined why the synthesized Ca2 ZnMoO6 phosphors had just one broad characteristic emission peak.