Abstract
Powder phosphors of CaLa1− x Eu x Al3O7, CaLa1− x Ce x Al3O7 and CaLa0.99− x Eu x Ce0.01Al3O7, where x = 0.01, 0.03, 0.05 and 0.07, were prepared by a combustion method. The powders were well characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and photoluminescence techniques. Emission spectra of Eu3+-doped powder phosphors showed strong red emission at 613 nm (5D0 → 7F2); no concentration quenching was observed. Generally, Ce3+ acts as an efficient sensitizer when doped with other trivalent lanthanide ions. However, interestingly, in the CaLaAl3O7 powder phosphors, the addition of Ce3+ with Eu3+ exhibited an adverse effect–decreased photoluminescence intensity. The reasons for this behavior are discussed.
Acknowledgements
Vijay Singh gratefully acknowledges Research Assistant Professorship at Chung-Ang University, Seoul (South Korea) from BK21 program. RPSC is grateful to Dr H.S. Maiti, Director, CGCRI and Dr Ranjan Sen, Head, GTL laboratory, CGCRI for their support and encouragement.