Blue Emitting SrBe1-xSi2+xO3-2xN2+2x:Eu2+ (x≈0.1)

In the search for materials for high-efficiency lighting applications, the color-point tuning of phosphors for inorganic phosphor converted LEDs (pcLEDs) is of special interest. We expand the recently explored phosphor class of SiBeONs (oxonitridoberyllosilicates) by the synthesis and characterization of SrBe1-xSi2+xO3-2xN2+2x:Eu2+. High temperature synthesis, starting from Sr2N, BeO, SiO2 and Si3N4, yields the target phase as the main product. Upon doping with Eu2+, the pale blue crystals exhibit blue luminescence with emission at 456 nm and a full width at half maximum (fwhm) of 66 nm/3108 cm(-1). The structure is an ordered variant of the LaSi3N5 structure type and was elucidated by single-crystal X-ray diffraction data. The network in SrBe1-xSi2+xO3-2xN2+2x:Eu2+ is highly condensed with a condensation degree of kappa=0.6 comprising corner-sharing [MX4] (M=Be, Si; X=O, N) tetrahedra, with mixed occupancies on both the ligand and central metal sites.