Ball Milling and Post Annealing as an Effective Route to Synthesize Co۱-xCuxSbS Paracostibite Thermoelectric Material

Metal sulfides containing non-toxic and earth abundant elements have emerged as new environmentally friendly thermoelectric materials. In the present work, a new, fast and large scale route to synthesise bulk nanostructured Co۱-xCuxSbS paracostibite is presented. Stoichiometric compositions of Co۱-xCuxSbS nanoparticles with ۰ ≤ x ≤ ۰.۰۸ were first processed by high energy ball milling for ۳ h, and then annealed at different temperatures between ۴۰۰ ºC to ۶۵۰ ºC for ۱ h. The phase transitions and diffusion process during annealing were thoroughly studied by x-ray diffraction (XRD) and scanning electron microscopy (SEM). Agglomerated nanoparticles with sizes in the range from ۴۰ nm to ۸۰ nm were obtained after ۳ h of ball milling, and remained below ۱۰۰ nm after annealing and hot pressing. The thermoelectric properties of hot pressed samples, including the Seebeck coefficient (S), electrical conductivity (σ) and thermal conductivity (k), were measured from room temperature up to ۷۲۳ K. All the samples exhibited a p-type semiconductor character at room temperature and underwent a transition from p-type to n-type conduction above ۴۷۳ K. a maximum ZT value of ۰.۱۲ was obtained for Co۰.۰۶Cu۰.۰۴SbS۴ at ۷۲۳ K.

کلیدواژه ها:

CoSbS ، thermoelectric ، nanostructure ، conduction type ، Cu-doping