Significant reduction of cathodoluminescent degradation in sulfide-based phosphors

The degradation of cathodoluminescent (CL) brightness under prolonged electron-beam excitation of phosphors has been identified as one of the outstanding critical issues for flat-panel field-emission displays. In this letter, we have demonstrated that a TaSi₂ coating on Y₂O₂S:Eu³⁺ phosphors substantially inhibits the cathodoluminescent degradation characteristics without reducing its efficiency. The coating was deposited by pulsed laser deposition of TaSi₂ targets onto a fluidized bed containing phosphor particles. Cathodoluminescent degradation experiments conducted at 2 keV and at 150μA/cm², showed that the CL brightness decreased by more than 50% after a Coulomb load of 15C/cm² on the uncoated material. In contrast, the TaSi₂-coated phosphor powders showed much less degradation, with CL brightness only decreasing by approximately 12% after electron irradiation with the same dose.