Narrow-Band Emitting Phosphor Na 2 Cs 2 Sr(B 9 O 15 ) 2 :Eu 2+ 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 Na 2 Cs 2 Sr(B 9 O 15 ) 2 :Eu 2+ 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 Na 2 Cs 2 Sr(B 9 O 15 ) 2 was located near the Ba site of the known narrow-band emitting sulfate phosphor BaSO 4 :Eu 2+ with a distorted local structure. We synthesized Na 2 Cs 2 Sr(B 9 O 15 ) 2 :Eu 2+ and characterized the luminescence properties by microspectroscopy. Na 2 Cs 2 Sr(B 9 O 15 ) 2 :Eu 2+ showed a violet luminescence peaked at 417 nm, and the full-width at half-maximum was as narrow as 26 nm (1497 cm -1 ).