Deep red emission enhancement in Mg₂₈Ge₁₀O₄₈:Mn⁴⁺ phosphor by Zn substitution

Zinc co-doped Mg₂₈Ge₁₀O₄₈:Mn⁴⁺ red phosphors are synthesized by a solid-state method. The effects of zinc on the phosphors have been investigated by varying the stoichiometric proportions of raw materials. Zn concentration affects the phosphor crystallinity, morphology, composition and energy structure. We have carried out the X-ray power diffraction (XRD), Field emission scanning electron microscope (FESEM), energy dispersion spectrum (EDS), element mapping, UV–Vis absorption measurement and X-ray photoelectron spectroscopy (XPS). The phosphorescence enhancement centered at around 660 nm is ascribed to ²E_g→⁴A_2g transition of Mn⁴⁺. The red emission Intensity of optimized sample is 3.08 and 1.64 times of Zn-free samples and conventional magnesium fluorogermanate phosphors, respectively.