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Analysis of optoelectronic properties and development of new persistent phosphor in Ce3+-doped garnet ceramics

Jumpei UEDA
2015 Journal of the Ceramic Society of Japan  
Ce 3+ -doped garnet materials have attracted a great deal of attention in w-LEDs and scintillators applications because of their various optical properties. In 2011, we reported intense photocurrent by blue light excitation in Y 3 Al 5¹x Ga x O 12 (Yttrium Aluminum Gallium Garnet, YAGG):Ce 3+ phosphors with high Ga content. With increasing Ga content in YAGG:Ce, the energy gap between the lowest excited 5d level (5d 1 ) and the conduction band (CB) decreases because the crystal filed splitting
more » ... al filed splitting of Ce 3+ becomes much smaller and the CB energy decreases. Based on the photoconductivity results, we concluded that Y 3 Al 2 Ga 3 O 12 : Ce 3+ luminescence is quenched by thermal ionization. Utilizing the thermally assisted photoionization by blue light excitation, we tried to prepare a blue light chargeable persistent phosphor. In 2013, we found that Cr 3+ ions act as suitable electron traps for persistent luminescence at room temperature in YAGG:Ce 3+ , and successfully developed the blue light chargeable persistent phosphors. In YAGG:Ce 3+ Cr 3+ persistent phosphors, the charging process (thermal ionization process) and detrapping process were controlled by CB energy engineering.
doi:10.2109/jcersj2.123.1059 fatcat:slrulievknbvvdqktyujqkhata