Highly Controllable and Efficient Synthesis of Mixed-Halide CsPbX3 (X = Cl, Br, I) Perovskite QDs toward the Tunability of Entire Visible Light

CsPbX₃ (X = Cl, Br, I) perovskite quantum dots (PQDs) have been intensively investigated on photoelectric devices due to their superior optical properties. To date, the stability of CsPbX₃ PQDs is still an open challenge. The previous mixed-halide CsPbX₃ PQDs were generally obtained via the anion-exchange method at 40 °C. Here, the single- and mixed-halide CsPbX₃ PQDs are synthesized at high temperature via the hot injection technique. The surface ligands could thus be strongly coordinated onto the surface of the PQDs, which dramatically improve the optical properties of the PQDs. The resulting CsPbX₃ PQDs have high quantum yield (QY, 40-95%), narrow full width at half-maximum (FWHM) (the narrowest FWHM <10 nm), tunable band gap (408-694 nm), and highly strong photostability. The variation of their emission peaks upon anion atoms is well-supported by the theoretical band gaps calculated by the density functional theory calculations with the alloy formula correction. Hence, these PQDs show great potential as good candidates for photoelectric devices.