Ca₂ Al₂ SiO₇ :Ce³⁺ phosphors for mechanoluminescence dosimetry

A series of Ce³⁺ ion single-doped Ca₂ Al₂ SiO₇ phosphors was synthesized by a combustion-assisted method at an initiating temperature of 600 °C. The samples were annealed at 1100 °C for 3 h and their X-ray diffraction patterns confirmed a tetragonal structure. The phase structure, particle size, surface morphology and elemental analysis were analyzed using X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy techniques. Thermoluminescence (TL) intensity increased with increase in ultraviolet (UV) light exposure time up to 15 min. With further increase in the UV irradiation time the TL intensity decreases. The increase in TL intensity indicates that trap concentration increased with UV exposure time. A broad peak at 121 °C suggested the existence of a trapping level. The peak of mechanoluminescence (ML) intensity versus time curve increased linearly with increasing impact velocity of the moving piston. Mechanoluminescence intensity increased with increase in UV irradiation time up to 15 min. Under UV-irradiation excitation, the TL and ML emission spectra of Ca₂ Al₂ SiO₇ :Ce³⁺ phosphor showed the characteristic emission of Ce³⁺ peaking at 400 nm (UV-violet) and originating from the Ce³⁺ transitions of 5d-4f (² F_5/2 and ² F_7/2 ). The photoluminescence (PL) emission spectra for Ca₂ Al₂ SiO₇ :Ce³⁺ were similar to the ML/TL emission spectra. The mechanism of ML excitation and the suitability of the Ca₂ Al₂ SiO₇ :Ce³⁺ phosphor for radiation dosimetry are discussed. Copyright © 2016 John Wiley & Sons, Ltd.