Rapid Direct Conversion of Cu2-xSe to CuAgSe Nanoplatelets via Ions Exchange Reactions at Room Temperature (original) (raw)
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Cu2Se and Cu Nanocrystals as Local Sources of Copper in Thermally ActivatedIn SituCation Exchange
ACS Nano, 2016
Among the different synthesis approaches to colloidal nanocrystals a recently developed toolkit is represented by cation exchange reactions, where the use of template nanocrystals gives access to materials that would be hardly attainable via direct synthesis. Besides, post-synthetic treatments, such as thermally activated solid state reactions, represent a further flourishing route to promote finely controlled cation exchange. Here, we report that, upon in situ heating in a transmission electron microscope, Cu 2 Se nanocrystals deposited on an amorphous solid substrate undergo partial loss of Cu atoms, which are then engaged in local cation exchange reactions with Cu "acceptors" phases represented by rod-and wire-shaped CdSe nanocrystals. This thermal treatment slowly transforms the initial CdSe nanocrystals into Cu 2-x Se nanocrystals, through the complete sublimation of Cd and the partial sublimation of Se atoms. Both Cu "donor" and "acceptor" particles were not always in direct contact with each other, hence the gradual transfer of Cu species from Cu 2 Se or metallic Cu to CdSe nanocrystals was mediated by the substrate and depended on the distance between the donor and acceptor nanostructures. Differently from what happens in the comparably faster cation exchange reactions performed in liquid solution, this study shows that slow cation exchange reactions can be performed at the solid state, and helps to shed light on the intermediate steps involved in such reactions.
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2012
The copper(II) complex of 1,1,5,5-tetra-iso-propyl-2-thiobiuret was used as a single source precursor for the synthesis of copper sulfide nanoparticles in a continuous flow process. The nanoparticles had a spherical morphology and were produced either as a pure Cu 7 S 4 or Cu 7 S 4 with minor impurities of Cu 9 S 5 .
Alloyed copper chalcogenide nanoplatelets via partial cation exchange reactions
ACS nano, 2014
We report the synthesis of alloyed quaternary and quinary nanocrystals based on copper chalcogenides, namely, copper zinc selenide-sulfide (CZSeS), copper tin selenide-sulfide (CTSeS), and copper zinc tin selenide-sulfide (CZTSeS) nanoplatelets (NPLs) (∼20 nm wide) with tunable chemical composition. Our synthesis scheme consisted of two facile steps: i.e., the preparation of copper selenide-sulfide (Cu2-xSeyS1-y) platelet shaped nanocrystals via the colloidal route, followed by an in situ cation exchange reaction. During the latter step, the cation exchange proceeded through a partial replacement of copper ions by zinc or/and tin cations, yielding homogeneously alloyed nanocrystals with platelet shape. Overall, the chemical composition of the alloyed nanocrystals can easily be controlled by the amount of precursors that contain cations of interest (e.g., Zn, Sn) to be incorporated/alloyed. We have also optimized the reaction conditions that allow a complete preservation of the size,...
Synthesis of Colloidal CuGaSe 2 , CuInSe 2 , and Cu(InGa)Se 2 Nanoparticles
Chemistry of Materials, 2008
We synthesize CuGaSe 2 , CuInSe 2 , and Cu(InGa)Se 2 nanoparticles in oleylamine with narrow size distribution using commercial grade copper, indium, gallium salts, and Se powder. Tunable nanoparticle size and composition are achieved through manipulation of reaction temperature and precursor concentrations. Ternary and quaternary materials are engineered by the judicious matching of ligand-precursor reactivities.
Structural, Optical and Thermal Characterization of Non-Stoichiometric Cu2-xSe Nanoparticles
2020
Fluorescent Cu2-xSe nanoparticles were prepared by a fast, versatile, microwave-assisted solvothermal method using microwave oven. Copper ions were from copper acetate dihydrate, selenite ions were from sodium selenite and reaction medium consisted of ethylene glycol and distilled water. The XRD patterns indicate that all the peaks are matching the peaks of non-stoichiometric Cu1.78Se and the average size of the nanoparticle is found to be 15nm. XRD, SEM, EDX and FTIR studies confirm the morphology and composition of Cu2-xSe nanoparticles. The optical band gap energy of the material was estimated using Tauc relation from UV-Visible spectrum. In the PL spectrum a sharp, intense blue emission peak is observed at 439.6nm. TGA shows that the prepared Cu2-xSe nanoparticles are very stable up to 486C. Keywords—Chalcogenide, Copper selenide, nonstoichiometric, microwave, solvothermal.
Journal of Alloys and Compounds, 2014
Fast ionic conductor acting as catalyst offers an efficient choice to produce one-dimensional nanomaterial with high crystallinity and flexible tolerance for lattice mismatch. We report the colloidal synthesis of CuGaS x Se 2Àx nanoribbons with the assistance of Cu 1.75 (SSe) nanocrystals for their intrinsic nature of fast ionic conductors. The structure of the as-prepared CuGaS x Se 2Àx nanoribbons is hexagonal wurtzite with (0 0 1) lattice planes exposed. The composition of nanoribbons can be tuned within the broad range by changing the relative concentration of Se/OA in stock solution. By monitoring the structures, compositions, and morphologies of the nanoribbons, it is confirmed that Cu 1.75 (SSe) nanocrystals are formed firstly, originating from the thermal decomposition of copper diethyldithiocarbamate precursors in the presence of dodecanethiol and selenium-oleylamine, and then act as the catalysts for the growth of the nanoribbons.
Colloidal Preparation of CuInSe2, CuGaSe2 and CIGS Nanoparticles
CuInSe 2 , CuGaSe 2 and CuIn (1Àx) Ga x Se 2 (CIGS) nanoparticles were synthesised from the diisopropyldiselenophosphinatometal complexes M x [ i Pr 2 PSe 2 ] n (M ¼ Cu(I), In(III), Ga(III); n ¼ 1, 3) by thermal decomposition of the precursors in HDA/TOP at 120-210 C or 250 C. The semiconductor nanoparticles obtained were characterized by powder X-ray diffraction (p-XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray (EDX) analysis. The diameters of the nanoparticles for CuInSe 2 , CuGaSe 2 and CuIn 0.7 Ga 0.3 Se 2 were found to be 4.9 AE 0.6 nm (at 180 C), 13.5 AE 2.9 nm (at 250 C) and 14 AE 2.22 nm (at 250 C) respectively. The p-XRD patterns for the nanoparticulate samples were assigned to the corresponding ICDD patterns for tetragonal chalcopyrite phase.