Luminescence properties of Mn2+-doped Li2ZnGeO4 as an efficient green phosphor for field-emission displays with high color purity

Green emitting Li2ZnGeO4:Mn2+ phosphors were synthesized through a high temperature solid-state reaction process. X-Ray diffraction, field emission scanning electron microscopy, photoluminescence (PL) and cathodoluminescence (CL) spectra were utilized to characterize the synthesized samples. Under UV and electron-beam excitation, the pure Li2ZnGeO4 sample shows a blue emission due to defects, while the Li2ZnGeO4:Mn2+ sample exhibits a green emission corresponding to the characteristic transition of Mn2+ (4T1 → 6A1). In particular, the CL intensity (brightness) of Li2ZnGeO4:Mn2+ is higher than that of commercial green phosphor ZnO:Zn. In addition, the CL properties of Li2ZnGeO4:Mn2+ phosphor, the dependence of CL intensity on accelerating voltage and filament current, the decay behavior of CL intensity under electron bombardment, and the stability of CIE chromaticity coordinates, have been investigated in detail. The results indicate that the as-prepared Li2ZnGeO4:Mn2+ phosphor has a good CL intensity and CIE coordinate stability with green emission under low-voltage electron beam excitation. Therefore, Li2ZnGeO4:Mn2+ is a promising green phosphor for application in full-color field-emission displays.