Formation and Transformation of Cu_2–xSe_1–yTe_y Nanoparticles Synthesized by Tellurium Anion Exchange of Copper Selenide

Abstract

Ion exchange reactions of colloidal nanoparticles post-synthetically modify the composition while maintaining the morphology and crystal structure and therefore are important for tuning properties and producing otherwise inaccessible and/or metastable materials. Reactions involving anion exchange of metal chalcogenides are particularly interesting, as they involve the replacement of the sublattice that defines the structure while also requiring high temperatures that can be disruptive. Here, we show that the tellurium anion exchange of weissite Cu 2−x Se nanoparticles using a trioctylphosphine−tellurium complex (TOP�Te) yields weissite Cu 2−x Se 1−y Te y solid solutions, rather than complete exchange to weissite Cu 2−x Te, with compositions that are tunable based on the amount of TOP�Te used. Upon storage at room temperature in either solvent or air, tellurium-rich Cu 2−x Se 1−y Te y solid solution nanoparticles transform, over the span of several days, to a seleniumrich Cu 2−x Se 1−y Te y composition. The tellurium that is expelled from the solid solution during this process migrates to the surface and forms a tellurium oxide shell, which correlates with the onset of particle agglomeration due to the change in surface chemistry. Collectively, this study demonstrates tunable composition during tellurium anion exchange of copper selenide nanoparticles along with unusual post-exchange reactivity that transforms the composition, surface chemistry, and colloidal dispersibility due to the apparent metastable nature of the solid solution product.

Temperature-Dependent Selection of Reaction Pathways, Reactive Species, and Products during Postsynthetic Selenization of Copper Sulfide Nanoparticles

“…This method was extended to create Cu 2−x (Se,Te) from Cu 2−x Se. 42 This current work adds a new example of anion exchange on a sulfide to incorporate selenide and offers a pathway to composition-morphology control that is inaccessible via direct or seeded growth.…”

Controlled Surface Modification of Cobalt Phosphide with Sulfur Tunes Hydrogenation Catalysis

“…We report a more controlled approach of modifying cobalt phosphide ( CoP ) with sulfur that includes the reaction of CoP with different phosphine sulfides (SPR 3 ). Phosphine chalcogenide reagents have previously been used for the synthesis and transformation of metal chalcogenide nanoparticles, − and SPR 3 are well-documented S-transfer reagents in molecular coordination chemistry. − We show that this S-transfer ability of the SPR 3 reagents enabled the addition of S to CoP at the surface and with varied number and type of S. Furthermore, we employed equilibration reactions of CoP with different SPR 3 to provide new insight into the thermochemistry of sulfur binding to CoP . We tested the bare and S-modified CoP as catalysts for the hydrogenation of cinnamaldehyde and showed that varied number and binding strength of S on the CoP surface diversely influenced the productivity, activity, and selectivity of the reaction.…”

Smart Design of Noble Metal–Copper Chalcogenide Dual Plasmonic Heteronanoarchitectures for Emerging Applications: Progress and Prospects

“…Dual plasmonic heteronanostructures could serve as parent nanocrystals to create a myriad of novel nanomaterials preserving the size and shape, particularly through the transformation of the copper chalcogenide component. Ternary Cu 2– x S y Se 1– y nanosystems have shown tunable plasmonic properties between 1000 and 1600 nm. , Recently, Cu 2– x Se 1– y Te y solid solutions were obtained as a result of partial tellurium anion exchange in weissite Cu 2‑x Se nanoparticles with tunable tellurium content based on the amount of its precursor . Therefore, combining such ternary semiconductors with noble metal NPs would form a new and unexplored type of dual plasmonic nanostructures.…”