Efficient and stable cyan-emitting CsPbBr quantum dots with zinc bromide inorganic passivation

The emission of cyan light (470-500 nm), an essential component of the visible light spectrum, plays a crucial role in lighting, display, and light communication. CsPbBr 3 quantum dots (QDs) have shown excellent performance in the green spectral regions, with high color purity, efficiency, and brightness. In order to shift the emission wavelength to the cyan, mixed-halide compositions and quantum-confinement engineering have been employed. Unfortunately, mixed-halide perovskites exhibit undesirable phase separation during optical and electrical excitations, leading to spectral instability. Quantum confinement in pure-halide QDs requires synthetic protocols that involve high loading of long-chain insulating ligands. In this study, we report color-stable cyan CsPbBr 3 quantum dots (C-PQDs) by surface passivation via incorporating Zn 2+ cations. The incorporation of ZnBr 2 into the precursor solution facilitates Zn 2+ and Br − substitution into the QDs surface/subsurface layers to induce passivation of existing Pb 2+ and Br − vacancies and increase the photoluminescence quantum yield from 53.6% to 96.4% at 480 nm. Moreover, after storage under ambient conditions for 30 days or exposure to ultraviolet light for 60 minutes or heating at 333 K, the PL intensity of ZnBr 2 -treated C-PQDs only shows a minimal decrease. Furthermore, white and cyan light-emitting diodes (LEDs) are successfully constructed, suggesting that the proposed ZnBr 2 -treated strategy can promote the development of perovskite materials for a wider range of optoelectronic applications. The present study proposes color-stable cyan CsPbBr 3 quantum dots (C-PQDs) by surface passivation incorporating Zn 2+ cations. The ZnBr 2 -treated C-PQDs exhibit a high photoluminescence quantum yield of 96.4% at 480 nm and exceptional stability.