Photoluminescence properties and crystal field analysis of a novel red-emitting phosphor K2BaGe8O18:Mn4+

- A novel non-rare-earth activated phosphor K2BaGe8O18:Mn4+ has been developed.
- The luminescence properties and crystal field analysis of phosphors have been investigated.
- The phosphors can be excited by UV and blue light and show red emissions.
- K2BaGe8O18:Mn4+ phosphors can be potential as a red-light component in w-LEDs.

Novel red-emitting phosphors K2BaGe8O18:Mn4+ (KBGO:Mn4+) were synthesized via the high-temperature solid-state reaction method. X-ray diffraction and Rietveld refinements illustrated that pure phase K2BaGe8O18 was obtained from the as-prepared samples. The excitation spectrum of KBGO:0.002Mn4+ monitored at 666 nm showed a wide band with two obvious peaks at 319 and 468 nm. It can be deconvoluted into four bands with maxima at 313, 350, 391 and 462 nm which corresponded to Mn4+-O2- charge transfer, Mn4+4A2-4T1, 4A2-2A2 and 4A2-4T2 transitions, respectively. Upon 468 nm excitation, the emission spectrum presented a narrow band from 600 to 700 nm (red region) with the maximum emission around 666 nm, which originated from Mn4+2Eg-4A2 transition in GeO6 octahedral environment. Therefore, K2BaGe8O18:Mn4+ phosphor can be considered as a red-emitting component candidate in UV and blue light excited white light-emitting diodes (w-LEDs).

189