摘要
The electronegative filling in skutterudites not only broadened the scope of filling atoms,but also facilitated the preparation of p-type skutterudites.However,the introduction of a single sulfur atom in the Co_(4)Sb_(12) cannot be achieved without charge compensation through the traditional equilibrium method.In the present study,the dual occupations of S-atoms by self-charge compensation were shown as the most stable forms under high pressure,and a series of p-type S_(y)Co_(4)Sb_(12-2y)S_(2y) skutterudites was successfully prepared by high-pressure-high-temperature(HPHT)method.The electronic structures and transport properties of as-obtained materials were investigated,and the related mechanisms were explored.The results suggested that the presence of S-impurities led to flattening of the electronic band that led to a higher Seebeck coefficient.The S-doped Co_(4)Sb_(12) displayed lower elastic modulus,elastic constant,and Debye temperature,thus indicating the chemical bond softening in skutterudites.The thermal conductivities of S_(y)Co_(4)Sb_(12-2y)S_(2y) compounds reduced monotonously with the increase in Scontent.This study provides a new and promising avenue for optimizing the thermoelectric properties of p-type Co_(4)Sb_(12).
基金
the financial support from the National Natural Science Foundation of China(Grant No.51772231 and 51972253)
the Fundamental Research Funds for the Central Universities(WUT:2017-YB-033,2020IB001,and 2020IB013).
