Improving the efficiency of a blue-emitting phosphor by an energy transfer from Gd3+ to Ce3+

The low-voltage efficiency of the blue-emitting phosphor, cerium activated yttrium silicate (Y1-mCem)(2)SiO5, has been improved by co-activating with gadolinium, (Y1-m-nCemGdn)(2)SiO5. Gd3+ improves the efficiency by transferring energy to Ce3+, and makes this phosphor a more promising candidate for low-voltage field emission flat panel displays. Low-voltage cathodoluminescence and photoluminescence measurements were made to determine the optimum concentrations of Gd3+ that yielded the most luminous efficient phosphor. For photoluminescence, Ce3+ Most efficiently luminesces at the excitation wavelength lambda(ex) = 358 nm. Co-activating with Gd3+ did not improve the photoluminescent efficiency because Gd3+ does not absorb at Ce3+ excitation energy, and thus cannot transfer energy. For low-voltage cathodoluminescence, co-activating with Gd3+ did improve the efficiency since Gd3+ was sufficiently excited, with the optimum composition found to be (Y0.8425Ce0.0075Gd0.15)(2)SiO5. (C) 2002 Elsevier Science B.V. All rights reserved.