Electronic structure and photo/cathodoluminescence properties investigation of green emission phosphor NaBaScSi2O7:Eu2+ with high thermal stability

摘要

As new light sources for next-generation illumination, white light-emitting diodes (LEDs) have been developed extensively and are commercially available due to their excellent advantages. However, the current white LEDs present in the market based on the combination of a blue chip and a yellow phosphor cannot satisfy the need for indoor illumination or some other colourful fields due to the lack of a sufficient red spectral component. Here we report a green phosphor, NaBaScSi2O7:Eu2+, which can be effectively excited using a near-ultraviolet chip and emit bright green light with extremely excellent thermal stability. The electronic structure and characteristic photoluminescence and cathodoluminescence properties as well as the thermal quenching properties were investigated in detail. The origin of the desired green luminescence was also determined by analyzing the crystal structure and measuring fluorescence lifetimes and the site-selective excitation and emission spectra. In addition, to investigate its application in field emission displays, the cathodoluminescence (CL) spectra of NaBaScSi2O7: Eu2+ as a function of the accelerating voltage, probe current and the electron radiation time were also measured and discussed in detail. The current results indicate that NaBaScSi2O7:Eu2+ can serve as a potential green phosphor for application in high-power white LEDs and field emission displays.