Synthesis and Characterization of Copper Sulfide Nanoparticles in Triton-X 100 Water-in-Oil Microemulsions

Abstract

Nanoparticles of copper sulfide have been synthesized by reacting a copper ammonia complex with an equimolar thiourea solution in Triton-X 100/cyclohexane water-in-oil microemulsions. The presence of an exceptionally sharp and blue-shifted peak at 475 ± 2 nm in the UV−vis spectrum reveals the formation of quasi-monodispersed, size-quantized particles. Using absorption spectroscopy, the formation of a chalchocite (Cu2S) phase is inferred. The peak position in the absorption spectra was found to be independent of net micellar water content as well as aging effect. It is attributed to the formation of a Cu(I) thiourea complex on the surface of the particles, which are hydrogen bonded to the polyoxyethylene (POE) chain of Triton-X 100 (TX-100). The role of thiourea in the tailoring of particles to the micellar periphery was confirmed by synthesizing the nanoparticles using other S2- agents like H2S, and Na2S. The role of the POE chain in mediating the adsorption was brought out by carrying out the reaction in microemulsions of POE containing surfactants other than TX-100. The kinetics of agglomeration has been studied and fits well in second-order rate law. A further enhancement in the solution stability of the particles was achieved by means of sodium hexametaphosphate.

Optical, photocatalytic properties of novel CuS nanoplate‐based architectures synthesised by a solvothermal route

“…Similar emission peaks are also given out in the researches by Xue and Wang [23,24]. Compared with bulk covellite CuS, which has a characteristic absorption band in the near-IR region [25], the absorption peaks of nanoplate-based CuS architectures obtained by us exhibit a large and distinct blue-shift, which is possibly attributed to the quantum confinement of the CuS nanoplates. The PL spectrum has a strong and broad blue emission band (464 nm) and a weak green emission band (550 nm).…”

Synthesis of Mesostructured Copper Sulfide by Cation Exchange and Liquid‐Crystal Templating

“…Konenkamp et al [2] and Alivisatos et al [4] have successfully utilized the ion exchange methods to fully transform the chemical composition of simple nanostructured inorganic materials while retaining their shapes. Although the exact mechanism by which the ions exchange while retaining the overall structure is still shown to possess interesting optical properties, [3] therefore, successful synthesis of mesostructured Cu x S shows a broad band with λ max at 375 nm, which, according to previously published results, [20,21] is indicative of Cu 2 S nanoparticle formation. It is interesting to note that we specifically observed an absorption band for Cu 2 S, when in fact Cu 2+ ions were added to the mesostructured CdS.…”

A general method for the large-scale synthesis of uniform ultrathin metal sulphide nanocrystals

“…S8). Both of their spectra show a strong absorption in the near infrared region, characteristic of covellite 18 . A discernible absorption peak is detected in the visible region at 465 nm, which is the lowest energy excitonic absorption peak of CuS nanosheet.…”