Tunable Room-Temperature Synthesis of Coinage Metal Chalcogenide Nanocrystals from N‑Heterocyclic Carbene Synthons

• Published in: Chemistry of materials Vol. 29; no. 3; pp. 1396 - 1403
• Main Authors: Lu, Haipeng, Brutchey, Richard L
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 14-02-2017; American Chemical Society (ACS)
• Subjects: INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; MATERIALS SCIENCE
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/acs.chemmater.6b05293

We present a new toolset of precursors for semiconductor nanocrystal synthesis, N-heterocyclic carbene (NHC)-metal halide complexes, which enables a tunable molecular platform for the preparation of coinage metal chalcogenide quantum dots (QDs). Phase-pure and highly monodisperse coinage metal chalcogenide (Ag2E, Cu2–x E; E = S, Se) QDs are readily synthesized from the direct reaction of an NHC-MBr synthon (where M = Ag, Cu) with alkylsilyl chalcogenide reagents at room temperature. We demonstrate that the size of the resulting QDs is well-tailored by the electron-donating ability of the L-type NHC ligands, which are further confirmed to be the only organic capping ligands on the QD surface, imparting excellent colloidal stability. Local superstructures of the NHC-capped Ag2S QDs are observed by TEM, further demonstrating their potential for synthesizing monodisperse ensembles and mediating self-assembly.