CsPbBr3 perovskite quantum dots with excellent water stability and optical properties synthetized through modifying with 6-aminohexanoic acid

CsPbBr ₃ perovskite quantum dots (PQDs) have broad application prospects due to their superior optoelectronic performance. However, the long-term stability issue in water hinders their practical commercial application. Herein, we introduced a short-chain zwitterionic compound, 6-aminohexanoic acid (EACA), and employed a ligand exchange post-treatment strategy after synthesizing CsPbBr ₃ PQDs to modify their surface properties and reduce surface defects. This strategy significantly improved the stability of CsPbBr ₃ PQDs in water, with the photoluminescence (PL) intensity remaining at 95 % of its highest intensity after dispersing in water for 12 h. Furthermore, even after being continuously exposed to water for 240 h, there was no shift in the emission peak wavelength, which remained at 521 nm. EACA-CsPbBr ₃ PQDs also exhibit a longer decay lifetime. The temperature-dependent analyses are investigated, and the relatively high activation energy indicates that the EACA-CsPbBr ₃ PQDs have the high thermal stability. Meanwhile, the EACA-CsPbBr ₃ PQDs can also be excited by X-rays, showing a linear response to X-ray radiation, which contributes to acquire excellent X-ray images. This study provides a simple and effective method for surface ligand treatment to achieve long-term water stability CsPbBr ₃ PQDs.