Optimization of interface properties in BiCuSeO-based thermoelectric devices via hot pressing process

BiCuSeO-based materials show great promise for thermoelectric generators in waste heat recovery due to their excellent thermoelectric properties. However, the limited focus on device development has hindered their industrial-scale implementation. Here, high-performance BiCuSeO-based compounds with exceptional thermal stability were synthesized and remained stable aging for 400 h, making them suitable for investigation in the device bonding process. The BiCu80AgP is identified as the optimal solder from eight candidates, effectively connecting the copper (Cu) electrode with BiCuSeO-based compounds. The optimized bonding process substantially resulted in an impressive interfacial shear strength of about 15 MPa and reduced interfacial resistance to 2.2 mΩ cm 2 . Interface analysis revealed the formation of diverse, complex compounds, with variations in their concentrations greatly affecting joint performance. Achieving a uniform distribution of these compounds effectively mitigated thermal expansion mismatches and extended joint longevity by a factor of 6.6. This research proposes a novel fabrication method for BiCuSeO-based thermoelectric devices utilizing BCu80AgP solder, providing a foundation for future advancements in this field.