Water-solvent spray-drying synthesis of KI-encapsulated CsPbI3 perovskite quantum dots for stable and high-performance red emission

CsPbI 3 perovskite quantum dots demonstrate tremendous potential in display and lighting technologies due to their excellent luminescent properties. However, conventional synthesis methods typically involve toxic reagents and complex procedures, which not only pose severe safety and environmental risks but also present long-term, serious challenges to the stability of the resulting products. Developing efficient and convenient synthesis strategies to achieve controllable preparation of high-quality red perovskite quantum dots represents a significant research direction in this field. Based on the concept of green synthesis, this study develops a spray-drying method using only water as the solvent to prepare CsPbI 3 perovskite quantum dots. In this method, CsPbI 3 perovskite quantum dots crystallize directly within KI, which not only achieves effective isolation from the external environment but also provides an iodine-rich atmosphere. Meanwhile, it effectively suppresses agglomeration of quantum dots, thereby enabling a rapid one-step synthesis of highly stable perovskite quantum dots. The prepared CsPbI 3 quantum dot crystals exhibit excellent performance, with a full width at half maximum (FWHM) of merely 43 nm. Thanks to the protection of the KI matrix, the obtained powder exhibits excellent phase stability in air, along with good redispersibility, facilitating its incorporation into ink systems. We have successfully applied it to patterned fluorescent anti-counterfeiting labels and further integrated it with blue GaN chips to fabricate red light-emitting diode (pc-LED) prototype devices with high brightness and color purity. The successful implementation of this method has significantly advanced its practical application in optoelectronic devices such as light-emitting diodes (LEDs) and wide-color-gamut displays.