PHASE DEVELOPMENT AND LUMINESCENCE IN CHROMIUM-DOPED YTTRIUM-ALUMINUM-GARNET (YAG-CR) PHOSPHORS

The phase development and luminescence of chromium-doped yttrium aluminum garnet (Y3Al5O12:Cr or YAG:Cr) phosphors, prepared by both a chemical precipitation technique and a solid-state reaction, were studied. The YAG structure formed at a much lower temperature and by a different phase development sequence when the chemical method was employed. The light output of the chemically synthesized powders, measured by laser excitation, was discovered to increase with increasing heat treatment temperature and was found to be brightest when the YAG:Cr phosphor had excess aluminum.