Effect of Citric Acid Amount in the Synthesis of LiGa₅O₈:Cr³⁺ Nano-Phosphor

Abstract: In this paper, LiGa₅O₈:Cr³⁺ nano-phosphor was successfully synthesized by the sol–gel method. Different from the high temperature solid phase method, we used citric acid as the chelating agent, and found that the amount of citric acid used significantly affects the final luminescence performance of LiGa₅O₈:Cr³⁺. The phase composition, crystal structure and luminescence characteristics of phosphors are analyzed by XRD, XPS, SEM, TEM, EDS, fluorescence spectroscopy. The kinetic series of LiGa₅O₈:Cr³⁺ were obtained. Comparing the different ratios of the total amount of metal ions to the amount of citric acid, when the ratio of the total amount of metal ions to the amount of citric acid is 1 : 2, the sample has fewer impurity phases, high crystallinity, regular grain shapes, and a size of about 250 nm. The fluorescence spectrum shows that the main excitation peak is 410, 608 nm and the main emission peak is 720 nm. The thermoluminescence spectrum shows that the sample with a ratio of 1 : 2 has more effective traps and can store more that can produce long-lasting luminescence. Carriers, the kinetic order is 2 at this time.