Alkali Lithosilicates: Renaissance of a Reputable Substance Class with Surprising Luminescence Properties.

A hitherto unknown synthetic access to alkali lithosilicates, a substance class first described by Hoppe in the 1980s, is reported. With the synthesis and characterization of NaK [Li SiO ] , a new representative has been discovered, expanding the family of known alkali lithosilicates. Astonishingly, NaK [Li SiO ] and the already established alkali lithosilicates Na[Li SiO ] as well as K[Li SiO ] display unforeseen luminescence properties, when doped with Eu . Na[Li SiO ]:Eu exhibits an ultra-narrow blue, K[Li SiO ]:Eu a broadband, and NaK [Li SiO ] :Eu a yellow-green double emission upon excitation with near-UV to blue light. Consequently, all of the investigated substances of this class of compounds are highly interesting phosphors for application in phosphor converted LEDs.