Facile preparation and control of Cu-Se compounds with various preparation conditions

Preparation of Cu-Se compounds, chalcogenide-based materials, is studied in this paper. The Cu-Se compounds were synthesized by using a hydrothermal method. This method possesses the advantages of simple preparation, facile manipulation, and the use of nontoxic supercritical water as a solvent. The chemical composition of the Cu-Se compounds was controlled by varying the copper source, reaction time, temperature, and surfactant. When CuCl₂ was used as a copper source, the Cu-Se compound tended to form a CuSe₂ phase. This phase was also formed at short reaction times and low reaction temperatures. Additionally, we investigated the change in the chemical composition of various Cu-Se compounds by using an acid treatment. The CuSe phase easily decomposed in acidic media while the CuSe₂ phase showed a high resistance to acidic media. This synthesized CuSe₂ can be used as a Cu(In,Ga)Se₂ (CIGS) precursor in a nonselenization method. This preparation method is expected to have potential applications in energy-related devices.