Facile synthesis and thermoelectric properties of Cu7Te4 compounds

Cu7Te4 powders were fabricated by both wet chemistry method and hydrothermal method. The phase structure and microstructure of Cu7Te4 powders were analyzed by X-ray diffraction (XRD) and scanning electronic microscope (SEM). The XRD results showed that no secondary phases were detected in as prepared Cu7S4 powders. The SEM observation showed that all samples are composed by same oriented plate-like grains with similar sizes about diameter 1-3 mu m and thickness 0.2-0.5 mu m. The Cu7Te4 powders prepared by wet chemistry were then densified to bulk materials. The thermoelectric properties of Cu7Te4 bulk material was measured, showing that the highest ZT value of 0.05 was obtained at 723 K.