Rational design and structural regulation of near-infrared silver chalcogenide quantum dots

Silver chalcogenides (Ag2E; E = S, Se, or Te) quantum dots (QDs) have emerged as promising candidates for near-infrared (NIR) applications. However, their narrow bandgap and small exciton Bohr radius render the optical properties of Ag2E QDs highly sensitive to surface and size variations. Moreover, the propensity for the formation of silver impurities and their low solubility product constants pose challenges in their controllable synthesis. Recent advancements have deepened our understanding of the relationship between the multi-hierarchical structure of Ag2E QDs and their optical properties. Through rational design and precise structural regulation, the performance of Ag2E QDs has been significantly enhanced across various applications. This review provides a comprehensive overview of historical and current progress in the synthesis and structural regulation of Ag2E QDs, encompassing aspects such as size control, crystal structure engineering, and surface/interface engineering. Additionally, it discusses outstanding challenges and potential opportunities in this field. The aim of this review is to promote the custom synthesis of Ag2E QDs for applications in biological imaging, and optoelectronics applications.