Eu2+:CsCaX3 (X = Cl, Br, I) perovskite nanocrystals in glasses for blue light-emitting applications

Abstract

Metal halide perovskite nanocrystals (PNCs) are considered as luminescent materials for next generation displays for their wide color gamut. Compared with green and red ones, the performance of blue light-emitting PNCs still lags far behind. Herein, divalent europium doped cesium calcium halide (Eu²⁺:CsCaX₃, X = Cl, Br, and I) PNCs are precipitated in glasses for the first time. These Eu²⁺:CsCaX₃ PNCs in glasses show blue emission from 435 nm to 458 nm with a maximal photoluminescence quantum yield of 81.9% and a full width at half maximum of 22–30 nm. These Eu²⁺:CsCaX₃ PNCs embedded in glasses exhibit good chemical-, thermal-, and photo-stabilities. Utilizing these Eu²⁺:CsCaCl₃ perovskite nanocrystal doped glasses as down-conversion layers and a commercial 395 nm UV LED chip as the excitation source, deep blue LEDs with an external quantum efficiency of 24.6% (I = 100 mA), a maximal luminous efficacy of 5.2 lm W⁻¹ (I = 50 mA), and long-term operation stability are realized. These results demonstrate that Eu²⁺:CsCaX₃ PNC doped glasses have promising applications in the field of blue LEDs.