Synthesis of Calcium Aluminate-Based Luminophores by the Citrate Nitrate Sol–Gel Process

Resumo

Microwave-assisted sol–gel process was used to synthesize calcium aluminate and luminescent materials based on it, which find wide use in the manufacture of construction materials, catalysts, optical emission sources, and display devices. The major processes involved in the formation of crystalline calcium aluminate were identified resorting to powder X-ray diffraction, thermal analysis, scanning electron microscopy, and IR spectroscopy data. Synthetic steps have moderate activation energies in the 44–260 kJ/mol range. Luminescence characteristics of the obtained crystal phosphors were measured. The increase in the synthesis temperature to 1200°C and the increase in the activator concentration to 5 mol % enhance the luminescence of the Eu³⁺-activated calcium aluminate-based luminophore. Further increase in the concentration of the activator ions leads to luminescence quenching caused by the concentration effect.