The thermoelectric effect, which converts waste heat into electricity, holds promise as a renewable energy technology. Recently, bismuth telluride (Bi2Te3)-based alloys are being recognized as important materials for practical applications in the temperature range from room temperature to 500 K. However, conventional sintering processes impose limitations on shape-changeable and tailorable Bi2Te3 materials. To overcome these issues, three-dimensional (3D) printing (additive manufacturing) is being adopted. Although some research results have been reported, relatively few studies on 3D printed thermoelectric materials are being carried out. In this study, we utilize extrusion 3D printing to manufacture n-type Bi1.7Sb0.3Te3 (N-BST). The ink is produced without using organic binders, which could negatively influence its thermoelectric properties. Furthermore, we introduce graphene oxide (GO) at the crystal interface to enhance the electrical properties. The formed N-BST composites exhibit significantly improved electrical conductivity and a higher Seebeck coefficient as the GO content increases. Therefore, we propose that the combination of the extrusion 3D printing process (Direct Ink Writing, DIW) and the incorporation of GO into N-BST offers a convenient and effective approach for achieving higher thermoelectric efficiency.

1. Introduction
2. Experimental
    2.1 Synthesis of n-type Bi1.7Sb0.3Te3 and ink for 3Dprinting sample
    2.2 Characteristics of the powder and samples
3. Results and Discussion
4. Conclusion
Acknowledgement

• Jinhee Bae(Department of 3D Printing Materials, Powder Materials Division, Korea Institute of Materials Science (KIMS), Changwon 51508, Republic of Korea)
• Seungki Jo(Department of 3D Printing Materials, Powder Materials Division, Korea Institute of Materials Science (KIMS), Changwon 51508, Republic of Korea)
• Kyung Tae Kim(Department of 3D Printing Materials, Powder Materials Division, Korea Institute of Materials Science (KIMS), Changwon 51508, Republic of Korea) Corresponding Author