Structure, photoluminescence, and thermal quenching properties of Eu doped Sr2AlxSi5−xN8−x/3 red phosphors

Abstract

Eu²⁺ doped Sr₂Al_xSi_5−xN_8−x/3 red phosphors have been synthesized by a solid state reaction method, with the aim of improving their thermal quenching properties. The XRD patterns confirm that Al³⁺ can efficiently substitute Si⁴⁺ in the Eu²⁺ doped Sr₂Si₅N₈ host. The crystal structure is studied by Rietveld refinement, selected-area electron diffraction (SAED) and solid-state NMR analysis. With an increase in x, the emission spectra show no obvious shift and the full width at half maximum (FWHM) increases from 86 to 94.2 nm. Remarkably, the thermal quenching properties are obviously improved as appropriate Al³⁺ substituted Si⁴⁺. The corresponding mechanism is discussed in detail based on the influence of size mismatch and the configurational coordinate model.