Composition is a well-known variable that controls material properties across length scales and has helped lead to a wide range of applications for metal chalcogenides. As the material composition is made more complex by the introduction of additional elements, challenges in controlling atom position emerge, which is especially crucial at the nanoscale. Several synthetic strategies have been identified as promising routes to access metal chalcogenide nanoparticles of various compositions. Of these, cation exchange is particularly versatile in accessing compositionally complex metal chalcogenide nanoparticles. Single reaction vessel syntheses have been less explored for complex metal chalcogenides, although they are desirable for their scalability, and ultimately, the translation of these materials into everyday technologies. Here, these two methods are investigated to identify mechanistic principles that can be used to access the widest variety of material compositions with the least number of synthetic steps. Specifically, we study nanoparticles containing copper, silver, and selenium elements synthesized using both cation exchange and a single reaction vessel method. Initially, we show that the cation exchange and single reaction vessel methods yield particles with tunable compositions but different atom arrangements. We then identify the main factor in the single reaction vessel synthesis that dictates atom arrangement in the final nanoparticle structures: copper precursor oxidation state. Specifically, we demonstrate that by controlling precursor chemistries, the single reaction vessel pathway can be used alone to access these two different atom arrangements in the resulting nanoparticle samples. Taken together, these results demonstrate the importance of identifying synthetic parameters that control atom position and the benefits of manipulating these factors to control final nanoparticle architecture.

Controlling atom arrangement in ternary metal chalcogenide nanoparticles using precursor oxidation state

ACS Spring Meeting 2021

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