X-Ray and Ultraviolet Luminescence of Li3Ta1−xNbxO4 Prepared by Flux Synthesis and Characterization of a New High Efficiency X-Ray Phosphor

✍ Scribed by C.R. Miao; C.C. Torardi

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 142 KB
• Volume: 145
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1999.8229

✦ Synopsis

The phase development and luminescence properties, under both X-ray and ultraviolet excitation, of the lithium orthotan-talate+lithium orthoniobate system, Li 3 Ta 1؊x Nb x O 4 for x ‫؍‬ 0 to 1, were examined. Using a 6ux synthesis technique, it was found that the levels of Nb-doping in monoclinic Li 3 TaO 4 and of Tadoping in cubic Li 3 NbO 4 are higher than previously reported. Under 30 kVp molybdenum X-ray excitation, Li 3 Ta 1؊x Nb 4 O 4 is an e7cient blue-emitting phosphor with broadband emission, peaking in the range of 390 to 435 nm. For x ‫؍‬ 0 to 0.1, the overall luminescence e7ciency is comparable to, or better than, a commercial calcium tungstate, CaWO 4 , Hi-Plus material. The composition Li 3 Ta 0.995 Nb 0.005 O 4 demonstrates an overall luminescence e7ciency that makes this phosphor 45% brighter than CaWO 4 Hi-Plus, thereby making it a potentially attractive candidate for use in medical diagnostic imaging systems. Under ultraviolet excitation, broadband blue emission is also observed. For all the Li 3 Ta 1؊x Nb x O 4 (x'0) solid solutions, the emission peak maximums agree well with those seen under X-ray excitation and are the result of Nb 5؉ emission.