Conversion Efficiency Improvement of Te-Based Thermoelectric Devices through Introduction of the SnTe Alloy Barrier Layer

Despite the excellent thermoelectric properties of Te, the element diffusion and reaction at the interface with the metal electrodes introduce a large contact resistivity (ρc), significantly reducing the conversion efficiency (η) of the device. Therefore, suitable barrier layers are being sought to optimize the connection between Te and metal electrodes. In this study, a Sn–Te alloy barrier layer is reported based on interfacial reaction. The results indicate that there is no reaction layer or microscopic defects at the interface of the SnTe/Te0.985Sb0.015 device. Additionally, the η of the single-leg device is approximately 4.7% at a temperature difference of 230 K. Notably, this ηmax is 100% higher than that of the Ni/Te0.985Sb0.015/Ni device. Meanwhile, the interface exhibits good thermal stability, with no significant changes observed in ρc, η, and interface microstructure after aging at 523 K for 18 days. This work provides valuable insights into optimizing the interface between thermoelectric materials and metal electrodes, which could lead to the development of more efficient and stable thermoelectric devices.