Intrinsic blue-white luminescence, luminescence color tunability, synthesis, structure, and polymorphism of K ₃ YSi ₂ O ₇

Two polymorphs of K3YSi2O7, crystallizing in the space groups P63/mmc (1) and P63/mcm (2) can be synthesized by high temperature flux crystal growth. The flux growth conditions can be fine-tuned to yield a phase pure sample of polymorph (2), however, not of polymorph (1), which always co-crystallizes with polymorph (2). Polymorph (2) was found to exhibit intrinsic bluish-white light emission. Further studies determined that doping europium and dysprosium onto the yttrium site of this polymorph could readily tune the luminescence, with the purest white light emission found for the K3YSi2O7: 10% Dy, 0.1% Eu composition (K3Y0.899Dy0.1Eu0.001Si2O7) (2-Dy,Eu).