Hydrothermal synthesis of hexagonal Cu_2−xSe microplates and optical properties

Hexagonal Cu_2−xSe microplates with lateral sizes of around 5-8 μm and 500 nm in thickness were synthesized by hydrothermal method using CuCl₂ and Se powder as raw materials, hydrazine hydrate as a reducing agent and oleylamine as an auxiliary agent. The morphology and crystalline structure of the product were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The influencing factors to product morphology were studied based on series of control experiments. The optical properties were investigated by UV-visible absorption spectroscopy and photoluminescence (PL) spectrum. The results show that the lateral size and uniformity of the hexagonal products can be easily regulated by changing reaction time and oleylamine quantity. The band gap energy of the Cu_2−x Se microplates is 2.25 eV.