A novel yellow-green emitting phosphor with hafnium silicon multiple rings structure for light-emitting diodes and field emission displays

A novel yellow-green emitting phosphor Na2HfSiO5:Eu2+ is successfully synthesized through solid-state reaction for the first time. Under the 369 nm excitation, the Na2HfSiO5:Eu2+ phosphors exhibit a broad yellow emission peaking at 551 nm with FWHM about 100 nm. The Na2HfSiO5:Eu2+ phosphors exhibit the asymmetric emission peaks owing to the Eu2+ partial occupation of four different Na+ sites with different environment. The energy transfer between Eu2+ ions appears by dipole-dipole interaction. A WLED lamp with high Ra (90) and low CCT (3875 K) was obtained by combing Na2HfSiO5:Eu2+ with BaMgAl10O17:Eu2+ (BAM), CaAlSiN3:Eu2+ and n-UV chip (lambda(max) = 380 nm). Under the low voltage and current conditions, the phosphor exhibits perfect stability and excellent anti degradation performance. All these results suggest that Na2HfSiO5:Eu2+ phosphor would be a potential candidate for n-UV LED and FED applications.