Urea assisted self combustion synthesis of CaAl2O4:Eu phosphor and its mechanoluminescence characterization

Europium doped monoclinic CaAl2O4 phosphors were obtained at low temperatures (500 degrees C) by the process of combustion of the corresponding metal nitrate-urea mixtures, over a period of 5 min. The product was investigated by X-ray powder diffraction. Mechanoluminescence (ML) emission spectra were recorded to investigate the luminescence centers. Two ML spectra were observed at around 455 nm and 606 nm. The ML intensity initially increased with time, attained an optimum value for a particular time, then decreased and finally disappeared. It is found that the ML intensity of the phosphor depends on temperature and the gamma ray dose given to it. The fading of the phosphor is quite low; therefore, it may be advantageously used for high temperature dosimetry applications.