Local structure and structural rigidity of the green phosphor β-SiAlON:Eu2+

Eu2+ inserted in β-Si3−xAlxOxN4−x is a material that shows exceptional promise as a green-emitting phosphor. Synchrotron X-ray and neutron scattering, in conjunction with first-principles calculations and Eu L3 X-ray absorption measurements, yield a consistent picture of the composition, and the favorable position for Eu2+ substitution in the crystal structure. The Debye temperature ΘD, which is a proxy for structural rigidity relating to effectiveness as a phosphor, is very high for the starting β-Si3N4 framework and is determined to decrease only slightly for the small amounts of Al3+ and O2− co-substitution that are required for charge balance associated with Eu2+ insertion.