Self-Activating Strontium Orthoborate Blue Phosphors Induced by Cation and Anion Deficiencies and Their Rare-Earth-Free White Ultraviolet Light-Emitting Diodes.

Self-activating blue-light-emitting strontium orthoborate phosphors, viz., Sr 3 B 2+ x O 6+3 x /2 and Sr 3 B 2+ x O 6+3 x /2-δ ( x ranges from -0.3 to 0.1), were obtained by varying the number of BO 3/2 and anion deficiencies. The integrated intensity observed from the oxygen 1s profile obtained via X-ray photoelectron spectroscopy indicated the relative concentrations of the oxygen vacancies in the Sr 3 B 2+ x O 6+3 x /2 ( x = 0, -0.1, and -0.3) and Sr 3 B 2 O 6-δ phosphors. The structures of Sr 3 B 2 O 6 , Sr 3 B 2.1 O 6.15 , Sr 3 B 1.9 O 5.85 , and Sr 3 B 2 O 6-δ with crystal orientations were analyzed based on high-resolution synchrotron powder X-ray diffraction data. A mixture of rare-earth-free blue Sr 3 B 2 O 6-δ and yellow Sr 2.45 Ba 0.5 Na 0.05 Al 0.95 Sn 0.05 O 4-α F 1-δ phosphors, incorporated on a 315 nm UV-LED chip, can generate a white-light UV-LED.