Effects of hydrothermal synthesis conditions on material properties of Cu-Se compounds for thermoelectric and photothermal energy conversion

Copper selenide (CuSe) is a promising material for these applications due to its unique properties such as meaningful electrical conductivity, Seebeck coefficient, and photothermal conversion efficiency. Here, a sys-tematic investigation into the hydrothermal synthesis and characterization of copper selenides (CuSe) was performed for thermoelectric and photothermal applications. Depending on the feeding ratio of the Cu and Se precursors and reducing agent, CuSe2, CuSe, and Cu2Se were synthesized at a relatively low temperature and within a limited time frame. The crystal growth and morphology of the compounds were composition-dependent, which led to variations in their electrical conductivity, Seebeck coefficient, and thermoelectric properties. Synthesized Cu-Se compounds also showed promising photothermal conversion characteristics, which were utilized to increase the energy harvesting of the thermoelectric module under light exposure. This study provide important insights into the relationship between the synthesis conditions and the material properties, as well as the potential of CuSe-based materials for thermoelectric and photothermal applications.