A facile synthetic route toward phase-pure colloidal Cu2GeS3 nanostructures mediated through metal xanthate precursors

Copper germanium sulfides (CGSs), a class of ternary I-IV-VI semiconductor metal chalcogenides, are considered quite desirable when it comes to efficient light harvesting materials for cost-effective and sustainable solar cells. Producing phase-pure CGS materials, free from binary impurities at the nanoscale is highly desirable. This report outlines a simple and easily scalable pathway toward phase-pure cubic Cu2GeS3 nanostructures via the thermolysis of copper and germanium isopropylxanthates in oleylamine (OAm). The crystal structure, phase purity, morphology, elemental composition and band gap of the as-synthesized Cu2GeS3 nanostructures were thoroughly evaluated via powder X-ray diffraction (PXRD), Raman spectroscopy, scanning and transmission electron microscopy (SEM and TEM), energy dispersive X-ray spectroscopy (EDS), and UV-Vis and diffuse reflectance spectroscopy (DRS), respectively. The band gap of these nanomaterials lies in an optimum range for solar cell applications. Finally, the pristine Cu2GeS3 nanocrystal-based prototype photoelectrochemical cells exhibit photovoltaic activity along with high photoresponsivity and stability under alternating light and dark conditions, which make them promising candidates for alternative low-cost photon absorber materials.

Automated summary

This study presents a simple method for producing phase-pure Cu2GeS3 nanostructures and thoroughly evaluates their structural characteristics, phase purity, morphology, elemental composition, and band gap. The results show that these nanomaterials are suitable for solar cell applications and exhibit good photoelectric properties and stability.