3D 프린팅으로 제조된 Bi₂Te₃계 열전소재의 열간등방가압 공정을 통한 전기적 특성 향상

Enhanced Electrical Properties of 3D Printed Bi₂Te₃-Based Thermoelectric Materials via Hot Isostatic Pressing

While Three-dimensional (3D) printing enables the fabrication of thermoelectric materials with customized geometries for arbitrary shape of heat sources, its pressureless sintering process leads to limited control over thermoelectric properties. Here, we investigated the effect of Hot isostatic pressing (HIP) treatment on the electrical properties of 3D printed Bi2Te3-based thermoelectric materials. After HIP treatment at 400°C and 150 MPa, both carrier concentration and mobility simultaneously increased, leading to a 21% enhancement in power factor from 2.43 mW m-1 K-2 to 2.93 mW m-1 K-2 at room temperature. The single parabolic band modeling revealed that nondegenerate mobility increased by 14% after HIP, indicating reduced carrier scattering. Microstructural analysis revealed that the average grain size increased and it contributed to enhanced carrier mobility. These results demonstrate that HIP treatment can be an effective post-processing approach for improving the thermoelectric performance of 3D-printed materials.