MgO:Li+ phosphor: In depth analysis of its structural, optical and thermoluminescent behavior after gamma irradiation

Abstract The purpose of this study is to synthesize Mg(1-x)O:xLi+ (x = 0, 1, 2 and 3 mol%) luminophors using Solution Combustion Synthesis(SCS) and investigate their potential applications in WLEDs and radiation dosimetry. The single phase (cubic) formation of samples is confirmed by Rietveld refinement of XRD data recorded at room temperature. The vibration characteristics are investigated by Fourier transform infrared spectroscopy. The diffuse reflectance spectra are recorded to calculate the values of the energy band gap of pristine and gamma exposed samples. SEM Micrographs reveal the formation of non-uniform shaped grains and a decrease in grain size with an increment in dopant concentration. Photoluminescence (PL) emission spectra exhibit broad bands around ~398 nm and ~485 nm that are ascribed to various defects in the MgO lattice. The influence of concentration on PL intensity indicates that 1 mol% dopant concentration is optimal. The CIE coordinates located in the blue region advocate the suitability of prepared samples for application in WLEDs. The dosimetric properties such as batch homogeneity, dose response and fading along with the influence of different γ-doses and dopant concentration on the TL intensity of γ-exposed luminophors are explored using recorded thermoluminescence (TL) glow curves of all samples. TL glow curves of lithium incorporated MgO at gamma doses of 50–500Gy show peaks around 150ᵒ-180ᵒ C. Besides, a shoulder peak ~300 °C is observed at higher doses > 1 kGy. Fading analysis indicates that maximum fading of ~10% is detected in the first 48 h s after the irradiation with decrement up to 75% on 15th day. The kinetic parameters of sample ML2 are calculated using three different techniques: the peak shape method, initial rise and the Ilich method.