Wet chemical synthesis of self-standing single-crystalline copper telluride Cu7Te4 nanorods: Characterizations and mechanism
Résumé
Single crystalline Cu7Te4 nanorods were obtained from a two-step synthesis route. The first step is the electro-
chemical deposition of self-standing tellurium nanorods on Pt-coated glass electrode in an ionic liquid electrolyte
acting as a structuring solvent. Afterwards, soft chemical transformation in Cu7Te4 is performed by immersing
the Te-covered electrode in a Cu(II) solution in presence of ascorbic acid acting as reducer at room temperature
and atmospheric pressure. Tellurium seems to undergo a reaction of disproportionation induced by the simul-
taneous presence of Cu(II) and Cu(I) into Te(IV) and Cu7Te4, which is supported by thermodynamic consider-
ations. The copper telluride nanorods were analyzed by XRD, SEM-EDX, HRTEM-FFT/SAED, EELS and XPS that
allowed to set the required parameters in terms of molar ratio of precursors in the bath to induce the targeted
chemical reaction. The analyses highlight the obtention of single crystalline Cu7Te4 with a homogeneous chemical composition along the nanorods. A detailed analysis of the microstructure shows the presence of
stacking local defects, leading to curved nanostructures.
