Narrow-Band Emitting Phosphor Na2Cs2Sr(B9O15)2:Eu2+ Discovered from Local Structure Similarity with Sulfate Phosphor

Narrow-band emitting phosphors are required to improve the performance of phosphor-converted light-emitting diodes. Here, we found a new narrow-band emitting phosphor Na2Cs2Sr­(B9O15)2:Eu2+ using the local structure similarity with a known narrow-band emitting phosphor. In a 2D scatter plot of the structural similarity between the local structures, the Sr site in Na2Cs2Sr­(B9O15)2 was located near the Ba site of the known narrow-band emitting sulfate phosphor BaSO4:Eu2+ with a distorted local structure. We synthesized Na2Cs2Sr­(B9O15)2:Eu2+ and characterized the luminescence properties by microspectroscopy. Na2Cs2Sr­(B9O15)2:Eu2+ showed a violet luminescence peaked at 417 nm, and the full-width at half-maximum was as narrow as 26 nm (1497 cm–1).