Europium(II)-Doped CsBr Nanocrystals in Glass for Spectrally Stable and Narrow-Band Blue-Light-Emitting Applications

Eu 2+ -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 Eu 2+ -activated metal halides limit their further development. In this paper, CsBr nanocrystals with tunable size and different Eu 2+ ion doping concentrations are precipitated in glass for the first time. Incorporation Eu 2+ 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/Eu 2+ nanocrystals in glass possess good spectral stability under different excitation energies and operating temperatures as well as operating currents. Employing CsBr/Eu 2+ 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/Eu 2+ 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.