Regulation of the Phase Composition on Zn1.4Al1.2Ge0.4O4: Cr3+ Phosphor Luminescence Color

We have proposed a type of Cr 3+ -doped Zn 1.4 Al 1.2 Ge 0.4 O 4 : Cr 3+ phosphor by replacing ZnAl 2 O 4 : Cr 3+ with germanium at different sintering temperatures in the high-temperature solid-phase method. Unlike the luminescence of common near-infrared ZnAl 2 O 4 phosphors, Zn 1.4 Al 1.2 Ge 0.4 O 4 : Cr 3+ phosphors have a more intense and persistent luminescence. At the same time, under the irradiation of 254 nm ultraviolet light, samples with different sintering temperatures show different luminescence colors. Phosphors exhibit long afterglow bluish white emission at sintering temperature below 1200 °C, and above 1200 °C (including 1200 °C), phosphors exhibit near-infrared long afterglow emission. This experiment systematically studies the effect of sintering temperature on Zn 1.4 Al 1.2 Ge 0.4 O 4 : Cr 3+ . The experimental results show that the abnormal blueish white emission of phosphors is related to the Zn 2 GeO 4 formed during sintering. Zn 2 GeO 4 is a self-luminous material with natural defects and shows a bluish white emission excited by ultraviolet rays. As the sintering temperature increases, the Zn 2 GeO 4 phase in phosphors gradually disappears, Ge 4+ ions enter the ZnAl 2 O 4 lattice to replace Al 3+ ions, and the emission color of Zn 1.4 Al 1.2 Ge 0.4 O 4 : Cr 3+ phosphors changes from bluish white emission to near-infrared emission. Zn 1.4 Al 1.2 Ge 0.4 O 4 : Cr 3+ phosphors showed different luminescence colors at different sintering temperatures, which enriched the luminescent properties of zinc aluminate-based phosphors.