Prominently optimized thermoelectric performance via possibly magnified carrier energy filtering effect in sandwich-structured p-type Cu-doped Bi0.5Sb1.5Te3 films

Energy filtering effect has been demonstrated an effective strategy to enhance the electrical transport properties and reduce the thermal conductivity of thermoelectric materials. However, to realize the energy filtering effect is so challenging, needing delicate design for specific system, which requires appropriate nano inclusions to well disperse in the pristine matrix and proper interface to produce potential energy barrier. Herein, we report a possible strategy to magnify the energy filtering effect in Cu-doped p-type CuxBi(0.5)Sb(1.5)Te(3) films prepared by intermittent magnetron co-sputtering technique. Due to the simultaneous optimization of the electrical conductivity and Seebeck coefficient with appreciable magnitude, the power factor shows a 564% enhancement for x = 0.015 in comparison with that of the undoped film. This enhancement is presumably due to a modulable energy filtering effect in the sandwich-structured film system, which provides a potential application for other thermoelectric materials.