Postsynthetic Degradation of Toxic Quantum Dots via Oleic Acid Complexation

Quantum-confined semiconductor nanocrystals (NCs) have found extensive applications in optoelectronics. However, their inherent toxicity, often due to the incorporation of heavy and toxic metals, poses significant environmental and health concerns. In this study, we introduce a postsynthesis degradation strategy for CdSe quantum dots (QDs) based on the use of oleic acid (OA), a long-chain fatty acid capable of complexing with heavy metals. The degradation of nanocrystals is monitored in situ using UV-vis spectroscopy, small-angle X-ray scattering (SAXS), and transmission electron microscopy (TEM). The results revealed that OA induces progressive degradation of the QDs, resulting in a reduction in their size and ultimately leading to the complete dissolution of the QDs within 24 h. The proposed mechanism has been validated for other NC systems, including PbS QDs and CdTe nanorods, highlighting its broad applicability across diverse materials. This strategy offers a sustainable and scalable route to mitigate the environmental risks associated with NC discharge.