Stable Blue-Emitting CsPbBr₃ Nanoplatelets for Lighting and Display Applications

Quantum-confined CsPbBr3 nanoplatelets (NPLs) with narrow full width at half-maximum (FWHM), large exciton binding energies, and precisely tunable thickness have become one of the promising materials for lighting and display. Still, the synthesis of CsPbBr3 NPLs with high photoluminescence (PL) intensity and excellent stability is challenging, hindering their large-scale application in lighting devices. Herein, we present a facile post-treatment strategy to enhance the PL performance of CsPbBr3 NPLs by surface passivation with a ZnBr2 solution. The ZnBr2-treated CsPbBr3 NPLs exhibit 90% photoluminescence quantum yield (PLQY) in the dispersion at 461 nm and 50% PLQY in thin films. Benefiting from surface defect passivation and ion migration suppression, ZnBr2-treated CsPbBr3 NPLs exhibit outstanding stability over pristine CsPbBr3 NPLs during long-term storage and exposure to a polar solution, light, and heating treatment. Specifically, the PL intensity of ZnBr2-treated CsPbBr3 NPLs dispersion shows a little decrease after storage at ambient conditions for 50 days or after mixing with ethanol for 160 h. Under challenging conditions including exposure to ultraviolet light for 300 h or heating at 70 °C for 30 min, their PLQY decreases only slightly.