Thermo electric measurement of nanocrystalline cobalt doped copper sulfide for energy generation

Submicron crystallites of CuS and Co doped CuS have been prepared by hydrothermal route. The structure of prepared crystallites were found to be hexagonal shape with space group P63/mmc and the size of the crystallites is in the range 89-127 nm. The morphology of the prepared CuS is nanoflower and there is no change in the morphology with cobalt doping. The d spacing and the cell parameters of the crystallites is found to be decreasing with doping of cobalt. The samples are pressed into pellets and their thermoelectric properties were investigated. CuS has an exothermic peak at 390 K as obtained in Differential Scanning Calorimetry (DSC) analysis so the electrical and thermal properties of all bulk samples were measured from 310 K to 370 K to avoid the phase change. The pure CuS samples prepared via hydrothermal synthesis reached the highest thermoelectric figure of merit (ZT) of 5.45 × 10−3 at 362 K and for the Cu1.6Co0.4S the ZT value is increased to 8.3 × 10−3 at 362 K.