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Li3 PO4 phosphor was prepared using a modified solid-state diffusion technique. In this work, photoluminescence, lyoluminescence and mechanoluminescence studies were carried out in a Li3 PO4 microcrystalline powder doped with different rare earths. In photoluminescence studies, characteristic emission of Ce and Eu was observed. The lyoluminescence glow curves of Li3 PO4 microcrystals show that lyoluminescence intensity initially increases with time and then decreases exponentially. The decay time consists of two components for all masses. The dependence of decay time, especially the longer component, on mass has been investigated. Experiments on γ-irradiated crystals have proved that the light emission originates from the recombination of released F-centres with trapped holes (V2-centres) at the sulfuric acid-solid interface. Incorporation of bivalent alkali in solid lithium phosphate leads to an enhancement of lyoluminescence. A possible explanation for the experimental results has been attempted. The phosphor has a mechanoluminescence single glow peak. Mechanoluminescence intensity under various loading conditions was investigated. It is observed that mechanoluminescence intensity increases with increasing impurity concentration and increasing piston impact velocity. The results may be considered as only being of academic interest in solid-state materials.

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The temperature and mass dependence of lyoluminescence intensity of γ-irradiated colored potassium chloride powder have been studied using a photomultiplier tube connected to an x-y recorder. The peak lyoluminescence intensity increases with increasing amount of solute added up to 50 mg and then tends to saturate. The lyoluminescence (LL) glow curves with mass of KCl microcrystals show that initially the LL intensity increases with time and then decreases exponentially with time. The decay time consists of two components for all the masses. The dependence of decay time, especially the longer component on mass, has been investigated. The temperature dependence of LL intensity shows that initially the peak LL intensity increases with temperature up to 60°C, and then decreases with further increase in temperature. The decay time tends to decrease with increasing temperature. An explanation for the experimental results has been attempted.