Design of a novel scandium silicate based blue-emitting phosphor with high efficiency and robust thermal stability for warm WLEDs and field emission displays

Abstract

A novel blue-emitting phosphor, Na₃ScSi₂O₇:Ce³⁺ (NSSO:Ce³⁺), was synthesized with a solid-state method at low temperature successfully. Its crystal structure, band structure, and photoluminescence and cathodoluminescence properties were researched in detail. The phase formation and the crystal structure were confirmed by powder X-ray diffraction analysis and the Rietveld refinement method, respectively. Under the excitation of n-UV light, the optimal NSSO:0.02Ce³⁺ phosphor can yield blue emission centered at 452 nm with a high quantum efficiency of 50.9%. The PL intensity of the NSSO:0.02Ce³⁺ phosphor remains at 71.46% of the initial value when the temperature is increased from room temperature to 150 °C, indicating good thermal stability. A WLED lamp was obtained by combining a 360 nm n-UV chip with Sr₂SiO₄:Eu²⁺, (Ca, Sr)AlSiN₃:Eu²⁺ and NSSO:0.02Ce³⁺ phosphors, in which the color coordinates, CCT and CRI are (0.360, 0.348), 4409 K and 90.9, respectively. Moreover, under low voltage electron bombardment, the phosphor can emit blue emission with high luminescence intensity, current saturation and resistance. All the results indicate that the NSSO:Ce³⁺ phosphor shows much potential for the application of both WLEDs and field emission displays (FEDs). Our research has also offered a new insight and perspective that using Sc-based sorosilicates as host can be an appropriate  strategy for developing excellent inorganic luminescence materials.