Search for: All records

Copper germanium sulfide-Cu2GeS3, is a ternary chalcogenide semiconductor that has attracted significant attention due to its tunable band gap, non-toxic and Earth-abundant elements in its composition, and versatile synthetic routes. However, the poor aqueous solubility of commonly used germanium precursors (GeO2, GeCl4) has hindered the development of green synthesis methods for Cu2GeS3. To overcome this challenge, we employed a diaquabis (glycolato-O,O′′) germanium(IV) (Ge-GA) prepared in house, as a water-soluble germanium precursor to produce Cu2GeS3 nanoparticles through a simple, one-step hydrothermal synthesis method. In addition to the Ge-GA, the hydrothermal synthesis of Cu2GeS3, utilizes inexpensive precursors: copper chloride dihydrate and thioacetamide, and leads to nanoparticles crystallizing in a monoclinic structure. The crystallographic and morphological properties were confirmed by X-ray diffraction with Rietveld refinement, Raman spectroscopy, high-resolution transmission electron microscopy (TEM) equipped with electron dispersive X-Ray spectroscopy (EDS), and scanning electron microscopy (SEM) with EDS. Optical characterization revealed a band gap of ~ 1.69 eV, while first-principles calculations were used to analyze the band structure and density of states. This work demonstrates the first aqueous synthesis approach of Cu2GeS3 nanoparticles, a facile method that could be extrapolated to other Ge-containing compounds. As Cu2GeS3 is a semiconductor, this synthesis route opens avenue for its facile translation to optoelectronic, thermoelectric and photovoltaic applications.