Synthesis and modification of red oxide phosphors for low voltage excitation

New red oxide phosphors Y2O3:EU3+,Si4+ and (Y,Gd)(2)O-3:EU3+,Si4+,Bi3+ are synthesized by a coprecipitation method. Relative cathodoluminescence (CL) brightness at low voltages (less than or equal to 1 kV) is analyzed, At the low voltage excitation, luminance of the synthesized phosphors is higher than that of other commercially available red phosphors Y2O2S:Eu3+ and Y2O3:Eu3+. In particular, the difference of relative brightness between the commercially available phosphors and the synthesized Y2O3:EU3+,Si4+ is larger at low voltages (less than or equal to 500 V) than at higher voltages. The synthesized (Y,Gd)(2)O-3:Eu3+,Si4+,Bi3+ phosphor gives the same level of bright-ness as that of Y2O3:Eu3+,Si4+ at voltages greater than 500 V. (Y,Gd)(2)O-3:EU3+,Si4+,Bi3+ is coated with a conductive material SnO2:Eu3+. The coating of SnO2:EU3+ shows a considerable improvement in brightness without a color shift. The excellent luminescence characteristics of (Y,Gd)(2)O-3:Eu3+,Si4+,Bi3+ coated with SnO2:Eu3+, studied using field emitter arrays, suggests that our synthesized phosphor is practically applicable to field emission display devices. (C) 2000 American Vacuum Society. [S0734-211X(00)03802-6].