We have employed a simple modular approach to install small chalcogenol ligands on the surface of CdSe nanocrystals.  This versatile modification strategy provides access to thiol and unique selenol and tellurol ligand sets via the in-situ reduction of R2E2 (R = tBu, Bn, Ph; E = S, Se, Te) by diphenylphosphine (Ph2PH).  The ligand exchange chemistry was analyzed by solution NMR spectroscopy, which demonstrates that reduction of the R2E2 precursors by Ph2PH directly yields the active chalcogenol ligands that subsequently bind to the surface of the CdSe nanocrystals.  Thermogravimetric analysis, FT-IR spectroscopy, and energy dispersive X-ray spectroscopy provide further evidence for chalcogenol addition to the CdSe surface with a concomitant reduction in overall organic content.  Time-resolved and low temperature photoluminescence (PL) measurements showed that, like thiol ligands, the selenol and tellurol ligands induce a fast, thermally activated quenching of the nanocrystal exciton population.  This PL quenching is likely due to hole transfer to a ligand-induced excited state and is more efficient at low temperature for the selenol and tellurol ligands.

Modular approach to colloidal CdSe nanocrystal ligand exchange with chalcogenols generated via the in-situ reduction of dialkyl and diaryl dichalcogenides

247th National Meeting (2014)

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