Cation exchange represents a promising avenue to colloidal nanomaterials with previously unavailable combinations of size, shape, and composition. The method has so far been restricted both in scope and in scale due to limitations in reactivity, ion mobility, and co-solubility of the nanoparticles and exchange reagents employed. In this presentation, we describe a cation exchange reagent permits rapid and highly efficient, room temperature exchange using both cadmium and lead chalcogenide quantum dots as starting materials. The reagent is based on a silver(I) complex that is prepared in situ and is soluble in toluene at concentrations up to 0.5 M. The reagent is air-stable and photostable for at least weeks on the shelf under fluorescent lighting. Optical spectra, elemental analysis, and TEM images provide evidence for rapid, room-temperature cation exchange using this reagent with CdSe and PbS quantum dots. Sizes of the resulting Ag<sub>2</sub>S and Ag<sub>2</sub>Se quantum dots are defined by the initial PbS or CdSe quantum dots. Partial exchanges are being explored as a path to mixed-metal species, with particular interest aimed at the spatial distribution of cations in these products. Finally, these silver-containing quantum dots are being employed in successive cation exchange reactions to achieve compositions not directly attainable from the original PbS and CdSe quantum dots at room temperature.

Room temperature, scalable cation exchange in PbS and CdSe quantum dots using a silver(I) complex

253rd National Meeting (2017)

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