Luminescence properties of Li-codoped Lu2SiO5:Ce thin-film phosphors prepared by sol–gel processing

• The Lu2SiO5:Ce thin-film phosphors were fabricated by sol-gel processing.
• A high concentration of Ce-doping (0.375 at.%) was achieved.
• The luminescent intensity was remarkably improved by Li-codoping.
• The mechanism of the enhanced luminescence was presented.

Lu2SiO5:Ce (LSO:Ce) is one of the promising candidates for applications in X-ray micro-imaging and flat panel display devices. In order to improve its luminescence performances, the effect of Li+ on Lu2SiO5:Ce (LSO:Ce) thin-film phosphors was investigated. The LSO: x mol% Ce, y mol% Li (x = 0.6–5, y = 0–8) thin-film phosphors were fabricated by sol-gel processing and characterized by measuring their structure and luminescence. The results indicated that an optimal Ce-doping concentration for photoluminescence (PL) emission intensity was achieved at x = 3 (equivalent 0.375 at%). After Li-codoping (y = 2), the PL intensity of the LSO:Ce thin-film phosphor was increased by a factor 1.9 with respect to the Li-free thin-film phosphor. The enhanced luminescence was dominated by the improvement of the crystallinity, and the decreased luminescence at y > 2 could be attributed to the creation of excessive defects, which reduced the crystallinity of thin-film phosphors.

Emission spectra of LSO: 3 mol% Ce, y mol% Li (y = 0–8) thin-film phosphors under 303 nm excitation. The inset shows the dependences of the spectral integral intensity (solid line) and the integral intensity ratio of Ce1/Ce2 (dash line) on Li-codoping concentration y.Figure optionsDownload as PowerPoint slide