Recent advances in synthetic methods and applications of colloidal silver chalcogenide quantum dots

Abstract Narrow bandgap colloidal semiconductor nanocrystals have attracted increasing attention in recent years and studies have demonstrated their significant applications in optics, electronics, biomedicine, materials science, and other areas. During the past decade, many studies have investigated colloidal silver chalcogenide (Ag 2 X, X = S, Se, Te) quantum dots (QDs) due to their numerous advantages, such as near-infrared (NIR) emission, ultralow toxicity, high photo-/colloidal stability, low cost, and facile synthesis. Compared with conventional NIR QDs (which contain heavy metal elements such as Cd, Hg, or Pb), NIR emissive Ag 2 X QDs avoid the intrinsic hazard of heavy metal ions and they have ultralow toxicity in biomedical applications. However, no previous review has summarized the synthetic methods and applications of Ag 2 X QDs in a systematic manner. In this review, we discuss previously reported synthetic methods and the advantages of directly synthesized and surface functionalized Ag 2 X QDs, as well as reporting their potential applications in bioimaging, chemo-/bio-detection, QD-sensitized solar cells, and photocatalysis, as well as antimicrobials and thermoelectric materials. Recent methods for synthesizing Ag 2 X QDs are discussed in detail. The unique optoelectronic properties of Ag 2 X QDs and their assemblies make these QDs excellent materials for a broad range of applications, and thus their assemblies and properties are highlighted. Finally, we suggest the future exploration of highly efficient synthetic methods and the potential application fields of Ag 2 X QDs.