Copper sulfide nanoparticles produced by the reaction of N-alkyldithiocarbamatecopper(II) complexes with sodium borohydride

Copper sulfide nanoparticles (CuxS-NP) surface-stabilized by dithiocarbamate (DTC) molecules were obtained with controlled size and shape by a novel one-step wet chemical methodology for the chemical transformation of a single-source precursor. The reaction of N-alkyldithiocarbamatecopper(II) complexes with NaBH4 in ethanol solution produces CuxS-NP of hexyl- (NP6), dodecyl- (NP12), and octadecyl- (NP18) carbon chains. The characterization of the particles was carried out by IR spectroscopy, Diffuse Reflectance Spectroscopy, Powder X-ray Diffraction, Thermal Analyses, and Transmission Electron Microscopy. The CuxS-NP are capped with DTC ligands which can tune the particle size. The CuxS phases obtained are closely related to the DTC chains length since NP6 produces Cu9S5 and CuS, NP12 yields Cu9S5 and Cu2S, finally, Cu9S5 and CuS are produced with NP18. In all the cases, the particles have a quasi-spherical shape, and the length of the DTC chain controls the particle size. The band gap of the CuxS-NP is around 3.0 eV, calculated by the Tauc baseline method, confirming their semiconductor nature and strong quantum confinement.