Synthesis, Crystal Structure, and Luminescence Properties of Tunable Red-Emitting Nitride Solid Solutions (CaSr)SiN:Eu for White LEDs.

A series of nitride solid solutions (CaSr)SiN:0.03Eu were successfully synthesized through the conventional solid-state method. The electronic crystal structure and photoluminescence characteristics were studied in detail. The excitation in the near-ultraviolet and blue regions of the samples shows a broad band in the 250-550 nm range, which can match well with the n-UV and blue lighting-emitting diode chips. Partial substitution of Ca by Sr results in a redshift emission, and the impacts of Sr content on the luminescence were researched in detail. Under 410 nm excitation, the phosphor exhibited tunable red emission from 616 to 653 nm by changing the concentration of Sr. Based on the crystal data, the emission can be fitted into three distinguished Gaussian components, which are attributed to the different Eu luminescence centers occupied in three disparate Ca (Sr) lattice sites. The temperature quenching property of the phosphor was also investigated, and the good thermal stability of the phosphors was analyzed through the activation energy for thermal quenching. And the obtained CCT values from 2642 to 2817 K are suitable for a warm white light region. All the results indicated that the phosphors have possible application in the warm white light-emitting diodes.