Strong red emission in Eu3+/Bi3+ ions codoped CaWO4 phosphors for white light-emitting diode and field-emission display applications

Abstract

The CaWO4:xEu3+ and CaWO4:0.08Eu3+/yBi3+ phosphors were synthesized via a high-temperature solid-state reaction method. The crystal structure and luminescence properties were investigated by X-ray diffraction patterns, photoluminescence excitation and emission spectra. The results indicate that both CaWO4:xEu3+ and CaWO4:0.08Eu3+/yBi3+ phosphors can be excited by near-ultraviolet and blue lights, and a strong red emission located at 616nm (5D0→7F2) corresponding to the characteristic emission of Eu3+ ions was observed in all the samples. Furthermore, the cathodoluminescence (CL) spectra as a function of filament current and accelerating voltage were also measured. Compared to the CaWO4:0.08Eu3+ phosphor, the CaWO4:0.08Eu3+/0.02Bi3+ phosphor had a stronger CL emission intensity with good Commission International de I’Eclairage chromaticity coordinate. The CaWO4:0.08Eu3+/0.02Bi3+ phosphor shows great potential for applications in white light-emitting diodes and field-emission displays as an excellent red-emitting phosphor.