Single-step solid-state synthesis of CeMgAl₁₁O₁₉:Tb phosphor

The green-emitting CeMgAl11O₁₉:Tb (CMAT) phosphor has been prepared at 1200 °C by the simple solid-state reaction using AlF₃ as a self-flux. This preparation temperature is much lower than those (1500-1700 °C) for conventional solid-state reaction and spray pyrolysis method. In particular, the complete process to produce high-quality phosphor particles was carried out through the single-step heat treatment of the mixture of corresponding oxide-type metal sources. An addition of AlF₃ as a self-flux significantly decreased the crystallization temperature of CMAT with plate-like shape. The particle morphology could be controlled from plate-like to spherical by using H₃BO₃ as an additional flux. Thus, an optimal morphology and luminescence characteristics of CMAT were achieved when both AlF₃ and H₃BO₃ fluxes were simultaneously used. Compared with conventional solid-state process, which is accompanied by the calcination step(s), and other alternative liquid solution techniques such as sol-gel method and spray pyrolysis, no use of active precursors and liquid media that are harmful to the environment is a distinctive advantage for the industrial purpose.