One-step electrosynthesis of CdS quantum dots stabilized by babassu oil and luminescent films deposited by DoD technology

Abstract

The electrochemical synthesis of CdS quantum-dots was carried out in a one-step electrochemical procedure using babassu oil (BO) as stabilizer. The electrochemical reduction of elemental sulfur in DMSO was investigated by cyclic voltammetry, showing the formation of polysulfides and S2−, such results are in agreement to literature. Thus, the CdS-BO electrosynthesis was realized in DMSO solvent and 30 mA constant current in cavity cell. The cadmium and sulfide ions were locally generated by simultaneous oxidation of a cadmium bar (sacrificial anode), and reduction of elemental sulfur in a graphite powder macroelectrode. The CdS-BO quantum-dots showed a UV–Vis absorption band at λmax = 387 nm with symmetrical emission band at λem = 547 nm, with a full width at half maximum (FWHM) of 124 nm. Lauric (C12H24O2, 48.9%) and myristic (C14H28O2, 20.4%) acids were identified as major components of the BO, in addition, 2.4% of free fatty acids were identified in the BO composition by titration, which explains the good stabilization of CdS QDs synthesized. The CdS-BO colloidal system was used as photonic ink and deposited on silica sheets by inkjet printing by drop on demand technology, without waste generation at all stages. The nanoparticles preserved luminescence after printing and drying, showing that the BO promotes an effective stabilization of the quantum dots.