Lutetium aluminum garnet activated by cerium (LuAG:Ce) materials containing functional materials (SiO2 and MgO) were prepared. These materials are used in LEDs, and they require a high thermal conductivity in order to minimize thermal aging. The functional materials were added in order to increase the thermal conductivity, as well as the luminescent properties of these materials. It was found that SiO2 did not improve the luminescent properties, but MgO ...