Visible Light-Driven Luminescence Evolution of CsPbBr₃ Quantum Dots via Surface Reconstruction

Abstract

Ligand exchange has been demonstrated as an efficient strategy to improve the photoluminescence quantum yield (PLQY) and stability of quantum dots (QDs). Long-term illumination can considerably accelerate the ligand desorption after ligand exchange because of the weak bonding between the ligand and QDs. Here, a novel light-driven luminescence evolution strategy in combination with ligand exchange is devised by using N-acetyl-L-cysteine (NAC) as a ligand. NAC is expected to coordinate with the uncoordinated Pb 2+ to improve the bonding between NAC and QDs. Light illumination is employed to accelerate the digestive ripening process and realize the uniform distribution of QDs. On the basis of the synergistic effect of NAC ligand exchange and light illumination, the CsPbBr 3 QDs show reduced surface defects with nearly 100% PLQY and remarkable stability in polar solvents. Furthermore, a white light-emitting diode is demonstrated with a high rendering index of 80.7 and color temperature of 5595 K.

Tuneable Efficient White Emission of Sb3+/Mn2+ Co-Doped Lead-Free Perovskites for Single-Component White Light-Emitting Diodes

“…Lead halide perovskites (CsPbX 3 , X = Cl, Br, and I) have received widespread attention due to their excellent optical properties, including high photoluminescence quantum yield (PLQY), narrow half peak width, and spectral tenability. − Recently, these excellent optical properties in combination with the superior defect tolerance contribute to great performance in the field of optoelectronic devices such as light-emitting diodes (LEDs), , photodetectors, and solar cells. − However, the toxic concern of heavy metal lead will inevitably cause irreversible harm to human health and the environment. The use of heavy metals in electronic and electrical equipment is strictly restricted under the Hazardous Substances Restriction Directive (RoHS) in European Union .…”