| 초록 |
Thermoelectric(TE) materials have been spotlighted for providing energy without a movable part and undesirable byproduct. Nevertheless, the development of TE materials have been stagnant due to the interdependence among electrical conductivity, Seebeck coefficient, and thermal conductivity. Since lattice thermal conductivity is the only independent parameter, a design for complex crystal structure with intrinsically low lattice thermal conductivity can be an effective approach to enhance TE figure of merit(ZT). Herein, we report the synthesis of Cu4Bi4Se9 complex thermoelctric system by Na doping. Through Na doping, effective mass dramatically increases from m0 = 0.18 me to m0 = 0.67 me at room temperature, which leads to enhancing power factor up to 1.05 μW cm-1 K-2 at 523 K. Consequently, 5% Na-doped sample results in higher ZT ~0.16 at 523 K, which shows 45% improvement compared to that of the pristine one. |
