Characterization and luminescence of Eu/Sm-coactivated CaYAl₃O₇ phosphor synthesized by using a combustion method

A novel red-emitting phosphor, CaYAl₃O₇: Eu³⁺, Sm³⁺, is synthesized by a combustion method at a low temperature (850℃), and the single phase of CaYAl₃O₇ is confirmed by powder X-ray diffraction measurements. The photoluminescence property results reveal that the red emission intensity of Eu³⁺ is strongly dependent on the Sm³⁺ concentration. Only the Eu³⁺ luminescence is detected in the Eu³⁺-Sm³⁺ co-doped CaYAl₃O₇ phosphor with 393 nm excitation. However, under the characteristic excitation (402 nm) of Sm³⁺, not only the Sm³⁺ emission but also the Eu³⁺ emission are observed. A possible mechanism of the energy transfer between Sm³⁺ and Eu³⁺ is investigated in detail.