Synthesis, structure and luminescence characteristics of a novel red phosphor NaLa9(GeO4)6O2:Eu3+ for light emitting diodes and field emission displays

Abstract

In order to explore a new kind of red phosphor for near ultraviolet white light emitting diodes (NUV-WLEDs) and field emission displays (FEDs), Eu³⁺ doped NaLa₉(GeO₄)₆O₂ was synthesized and its luminescence properties were studied for the first time for fundamental research. The results indicate that all samples crystallize in the hexagonal crystal system with the P63/m space group. Eu³⁺ doped NaLa₉(GeO₄)₆O₂ with the content of 0.07 has optimal photoluminescence properties, with a dominant red emission peak at 612 nm (⁵D₀–⁷F₂) with CIE coordinates of (0.64, 0.35) under 392 nm excitation and the quantum efficiency of 45.2%. Additionally, the thermal quenching property has been studied and its possible mechanism has also been expounded. Furthermore, the cathodoluminescence (CL) property was investigated and the result reveals that the sample has excellent degradation properties for FEDs. The study reveals that NaLa₉(GeO₄)₆O₂:0.07Eu³⁺ could be a suitable red-emitting phosphor candidate for NUV-WLEDs and FEDs.