Study of the phosphorescent properties of CdSiO3 doped and co-doped with transition metals (Mn2, Ni2+, Cr3+)

Cadmium silicate is a phosphor of high technological interest. This material can be widely used in areas such as safety indication, lighting in emergency and optical data storage. In this work, we have studied the phosphorescent properties of CdSiO3 in pure state, doped with Mn2, Ni2+ and Cr3+, and co-doped with (Mn2+, Cr3+) and (Mn2+, Ni3+). The powders were synthesized by a conventional solid-state method, using low-purity industrial reagents. During the synthesis, several parameters such as milling conditions, time and temperature of the calcination, were tested to produce single crystalline phase CdSiO3 . The best conditions found for the calcination were 1000 deg C for 8 hours. The single crystalline phase CdSiO3 was obtained after two milling and calcination stages. The optical properties of the synthesized powders were studied via photoluminescence and radioluminescence techniques. The emission spectra of the pure, doped and co-doped samples show broad emission bands near 496 and 593 nm. There are some evidence that the long-lasting phosphorescence of the cadmium silicate is due to the presence of cadmium vacancies. The presence of co-dopants has the function of promoting energy transfer that enhance the lifetime in the excited state. (author)