Size and Shape Modulation of Cu₂S Nanoplates via Chemical Reduction with NaOH and NH₃·H₂O

Copper(I) sulfide (Cu₂S) has electrical, optical, and thermoelectric properties that make it a promising material for a variety of applications, including energy conversion and antibacterial coatings. Nevertheless, the current synthesis and morphological modulation of Cu₂S typically focuses on thermolysis of the copper and sulfur precursors, is procedurally complex, and demands expensive equipment. In this article, a facile, high-yield, three-step, low-temperature aqueous synthesis alternative for Cu₂S nanoplates is introduced. By variations of the reaction temperature, reducing agent concentration, and pH modifier (NaOH or NH₃·H₂O), the morphological characteristics can be controlled. As confirmed with scanning and transmission electron microscopy, the lateral extent of the synthesized Cu₂S nanoplates can be tuned from around 30 nm to around 300 nm simply by varying the heating conditions from 10-100 °C. A similar effect is more subtly observed by varying the concentration of the reducing agent. In addition to size variance, the morphological properties of the Cu₂S nanoplates can be changed by using different bases for the reaction. Characterization of the composition and crystalline structure of the materials has also been performed using energy-dispersive spectroscopy and X-ray diffraction, and optical properties are investigated by UV-visible and near-infrared spectroscopy (UV-vis-NIR). The synthesis pathway described in this paper can be easily performed and feasibly scaled, which is advantageous as the retrieved material is suitable for diverse applications, such as its use in battery electrodes, photonic and charged-particle sensors, and radiation shielding.