Novel Narrow Band Cyan‐Green Phosphor LiK 7 [Li 3 SiO 4 ] 8 :Eu 2+ with Enhanced Suppression of Second Broad Band Emission

LiK 7 [Li 3 SiO 4 ] 8 :Eu 2+ (LKLSO:Eu 2+ ) was synthesized by a high‐temperature solid‐state reaction. It is accessible from K 2 CO 3 , Li 2 O, SiO 2 , and an Eu‐source (Eu 2 O 3 ) by conventional solid‐state reaction in nickel crucibles under a constant flow of forming gas. The crystal structure of LKLSO has been determined by single‐crystal X‐ray diffraction and it crystallizes in the tetragonal space group I (no. 88) with the lattice parameters a =1560.83(5), c =1278.23(4) pm, and a volume of V =0.31140(2) nm 3 . The compound is isostructural to NaK 7 [Li 3 SiO 4 ] 8 :Eu 2+ but, in contrast, features an enhanced suppression of the second broad band emission through the specific channel filling in the crystal structure. Despite the observed positional disorder in the structure, the cyan‐green phosphor shows a narrow band emission with a maximum at 511 nm and a fwhm of 45 nm (0.215 eV).