Color-control of the persistent luminescence of cadmium silicate doped with transition metals

The structural and optical characterization of cadmium silicate (CdSiO3) doped with transition metals is reported. This crystalline system presents intrinsic luminescence and is usually studied as host matrix for rare earth ions. In this work, CdSiO3 was doped with Mn, Ni and Cr to produce multicolored luminescent materials. Single crystalline CdSiO3 was obtained via solid state synthesis at 1000 °C/8 h. The valence of the dopants inserted in the host matrix was determined via XANES as 3+ for Cr, 2+ for Ni and both 2+ and 3+ for Mn, according to XANES studies. The optical absorption spectra of the samples presented wide bands in the visible region that were associated with the internal transitions of the dopants. All the samples presented photoluminescent bands near 420 nm, 496 nm and 591 nm, with different relative intensities that yield characteristic luminescence colors ranging from blue to red.