Novel zirconium silicate phosphor K2ZrSi2O7:Eu2+ for white light-emitting diodes and field emission displays

Abstract

A novel blue-emitting zirconium silicate phosphor K₂ZrSi₂O₇:Eu²⁺ was prepared by solid-state reaction for the first time, and its crystal structure was determined from the XRD profiles by using Rietveld refinement and high-resolution transmission electron microscopy (HRTEM). The photoluminescence properties were investigated for the possible application in white light-emitting diodes (LEDs). The excitation spectra of the Eu²⁺ doped K₂ZrSi₂O₇ phosphor show broad band excitation in the 250–410 nm region, and upon excitation at 350 nm, this phosphor showed a strong blue emission centered at 462 nm (full-width at half-maximum (FWHM) ∼ 70 nm). The thermal stability can be enhanced significantly by solid solution. The cathodoluminescence properties of K₂ZrSi₂O₇:Eu²⁺ were also studied. Under continuous low-voltage electron bombardment, the phosphors display excellent degradation resistance and good color stability. A white LED fabricated with this phosphor and yellow-orange emitting phosphor Sr₃SiO₅:Eu²⁺ on a LED chip (λ_max = 375 nm) was discussed. Driven by a 350 mA forward bias current, the fabricated lamp gives intense white light with a higher color rendering index of 86. All the results indicate that this phosphor has potential application in LEDs and FEDs.