Fully Aqua-Mediated Ripening of Perovskite Quantum Dots with 98% PLQY and Self-Assembly into Bioimaging Nanoparticles

Ongoing research on perovskite quantum dots (PQDs) spanning diverse areas such as crystallography and biology represents a rapidly expanding frontier in nanotechnology, yet is still limited by the poor water stability and inadequate biocompatibility. Herein, this study reports an ultra-simplified, eco-friendly, cost-effective, and industrial-grade fully aqua-mediated ripening (FAMR) technique for aqueous-PQDs (APQDs) with tunable spectra, achieved by directly stirring the raw precursors with zwitterionic ligands in water at a set pH via Ostwald ripening crystallization.These APQDs exhibit high photoluminescence quantum yields (PLQYs) of up to 82.8% (blue), 98.2% (green), and 92.4% (red), respectively. Owing to the highly efficient bidentate binding of zwitterionic ligands onto APQDs surfaces, as confirmed by theoretical studies, the APQDs demonstrate excellent water storage stability for over 1 month and can retain an impressive 83% of the initial PL intensity after 3 months when transferred to EtOH. With elevated exciton binding energy, extended carrier lifetimes, and lower defect density, APQDs also outperform conventional oil-phase PQDs in terms of thermal and UV irradiation stability. Based on this, water-soluble fluorescent nanoparticles (NPs) are synthesized through self-assembly of APQDs and DSPE-PEG 2000 using EtOH and water as biphasic solvents. Finally, the APQDs@NPs, possessing desired luminescence and biocompatibility, exhibited excellent bioimaging performance in U251 cells.