Eu2+-activated metal halides with narrow-band
blue emission
have attracted special attention in solid-state lighting and full-color
display. However, the poor spectral stability and high sensitivity
to oxygen and moisture of Eu2+-activated metal halides
limit their further development. In this paper, CsBr nanocrystals
with tunable size and different Eu2+ ion doping concentrations
are precipitated in glass for the first time. Incorporation Eu2+ ions into CsBr nanocrystals enables a narrow-band blue PL
at 447 nm with a full width at half-maximum of 24 nm and a high photoluminescence
quantum yield of 55.8%. More importantly, these CsBr/Eu2+ nanocrystals in glass possess good spectral stability under different
excitation energies and operating temperatures as well as operating
currents. Employing CsBr/Eu2+ nanocrystal-doped glass as
the blue-emitting convertor, a blue-light-emitting device with an
external quantum efficiency of 11.2%, a luminous efficacy of 3.8 lm/W,
and a high color purity of 96.6% is realized, and the potential of
CsBr/Eu2+ nanocrystal-doped glass toward high-performance
white-light-emitting devices is also demonstrated. These results provide
an avenue for blue-emitting materials with narrow line width and good
spectra stability.