Europium(II)-Doped\nCsBr Nanocrystals in Glass for\nSpectrally Stable and Narrow-Band Blue-Light-Emitting Applications

Eu<sup>2+</sup>-activated metal halides with narrow-band\nblue emission\nhave attracted special attention in solid-state lighting and full-color\ndisplay. However, the poor spectral stability and high sensitivity\nto oxygen and moisture of Eu<sup>2+</sup>-activated metal halides\nlimit their further development. In this paper, CsBr nanocrystals\nwith tunable size and different Eu<sup>2+</sup> ion doping concentrations\nare precipitated in glass for the first time. Incorporation Eu<sup>2+</sup> ions into CsBr nanocrystals enables a narrow-band blue PL\nat 447 nm with a full width at half-maximum of 24 nm and a high photoluminescence\nquantum yield of 55.8%. More importantly, these CsBr/Eu<sup>2+</sup> nanocrystals in glass possess good spectral stability under different\nexcitation energies and operating temperatures as well as operating\ncurrents. Employing CsBr/Eu<sup>2+</sup> nanocrystal-doped glass as\nthe blue-emitting convertor, a blue-light-emitting device with an\nexternal quantum efficiency of 11.2%, a luminous efficacy of 3.8 lm/W,\nand a high color purity of 96.6% is realized, and the potential of\nCsBr/Eu<sup>2+</sup> nanocrystal-doped glass toward high-performance\nwhite-light-emitting devices is also demonstrated. These results provide\nan avenue for blue-emitting materials with narrow line width and good\nspectra stability.