Pioneering perovskite quantum dot nanosensors for heavy metal ion detection: mechanisms, design, and industrial applications

Abstract

Perovskite quantum dots (PQDs) are a transformative platform for ultrasensitive heavy metal ion detection, leveraging high photoluminescence quantum yield (PLQY, 50–90%), narrow emission spectra (FWHM 12–40 nm), tunable bandgaps, and defect-tolerant optoelectronic properties. This review is the first systematic evaluation of PQD-based nanosensors for detecting Hg²⁺, Cu²⁺, Cd²⁺, Fe³⁺, Cr⁶⁺, and Pb²⁺, elucidating key mechanisms like cation exchange, electron/hole transfer, Förster resonance energy transfer, and surface trap-mediated quenching. Advanced synthesis methods, including hot-injection, ligand-assisted reprecipitation, and microwave-assisted techniques, enable precise control over size, crystallinity, and surface chemistry. Lead-based PQDs (e.g., CsPbX₃) achieve limits of detection (LODs) as low as 0.1 nM with rapid response times (<10 s), while lead-free variants (e.g., Cs₃Bi₂X₉, CsSnX₃) offer eco-friendly alternatives with enhanced aqueous stability. PQD@MOF composites and ratiometric designs enhance selectivity in complex matrices, surpassing carbon quantum dots and semiconductor QDs in sensitivity and versatility. Applications include industrial wastewater remediation, lubricant quality control, and environmental compliance, ensuring ecosystem protection and product integrity. This seminal work addresses challenges like aqueous instability, Pb toxicity, scalability, and matrix interference, benchmarking PQDs against alternative nanomaterials. Future directions include comparisons with other nanoparticles, multiplexed sensing platforms, and sustainable lead-free innovations. By integrating fundamental insights with practical applications, this review establishes PQDs as a high-impact paradigm for advancing heavy metal ion sensing in industrial and environmental contexts, guiding innovations in sensitivity, selectivity, and scalability.