Alkali-germanate glass-ceramics doped with manganese and chromium ions

This work is devoted to investigation of the spectral and luminescent properties of lithium-germanate, lithium-sodium-germanate and lithium-zinc-germanate glass ceramics obtained by high-temperature heat treatment of the initial glass doped with manganese and chromium ions. It is shown that when sodium is added to Mn-doped lithium germanate glassceramics, the luminescence intensity of Mn4+ ions increases from 5 to 37% of the quantum yield. In lithium-zinc-germanate glass-ceramics, the simultaneous presence of Mn4+ ions in an octahedral environment with red luminescence near 670 nm and Mn2+ ions in a tetragonal environment with long persistent green luminescence at 540 nm is found. The maximum quantum yield for red luminescence was 47%, for green luminescence - 23%. The intensity ratio of different luminescence bands depends on the ratio of lithium / zinc ions in the glass composition. In all studied glass-ceramics, Cr3+ ions demonstrate weak luminescence with a maximum in the region of 690- 698 nm. The possibility of using the materials under study as a luminescent red radiation source material is considered.