4-Chlorrate Assisted in Situ Passivation of CsPbCl3 Perovskite Quantum Dots with High Water Stability for Light-Emitting Diode

The application of all inorganic halide perovskite quantum dots (PQDs) in the field of optoelectronic devices has made exciting progress. However, the preparation of CsPbX₃·PQDs with high water stability is still a great challenge. In this article, the direct synthesis of CsPbCl₃·PQDs in water using 4-chlorobutyric acid (CBA) and oleamine (OLA) as surface ligands was proposed for the first time. Transmission electron microscopy spectra show that the QDs synthesized in water have good crystallinity and monodispersity. At the same time, CBA-CsPbCl₃·PQDs synthesized by this method continuously emitted light in water for more than 400 h. In contrast, OA-CsPbCl₃·PQDs were almost completely quenched after only 20 min of mixing with water. X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and hydrogen spectroscopy nuclear magnetic resonance were used to verify the passivation effect of CBA on the surface of QDs. The carboxyl ligands provided by CBA form a stable hydrophobic shell on the surface of CsPbCl₃·PQDs, which makes CsPbCl₃·PQDs have excellent water stability. In this study, CsPbCl₃·PQDs with excellent water stability were synthesized with CBA/OLA as the surface ligand for the first time, which provides an effective way to explore perovskite light-emitting diodes with good water stability.