Engineering the Photoluminescence of CsPbX3 (X = Cl, Br, and I) Perovskite Nanocrystals Across the Full Visible Spectra with the Interval of 1 nm

Fluorescent CsPbX3 (X = Cl, Br, I) perovskite nanocrystals (NCs) are compelling candidates for illumination and display applications because of the high photoluminescence quantum yields (PLQYs) narrow PL emission spectra, and in particular, the potential to tune the emission spectra in the entire visible range. However, limited by the current preparation strategy, the successive adjustment of PL emission across the full visible spectral range with very small interval, like conventional semiconductor quantum dots, is still challenging. In this work, we demonstrate the capability to tune the PL emission of CsPbX3 NCs in the full visible range with the interval of 1 nm on the basis of a modified anion-exchange route. Highly luminescent CsPbCl3 NCs with PLQY up to 34.2% are foremost prepared using alkanoyl chlorides as the chlorine source and further employed to perform anion exchange. A successive and accurate adjustment of the PL emission is achieved with the addition of ZnX2 (X = Br and I) aqueous solution and assisted by ultrasound to improve the reactivity of halogens in the anion exchange. Besides the accurately tunable PL emission position, the as-prepared CsPbX3 NCs exhibit good phase/chemical stability, high PLQY, and narrow PL emission spectra.