• • Ni5.75SnTe5 contact layer achieves a low interfacial contact resistivity of 3.7 μΩ cm2, lower than reported for SnTe-based devices, enabling higher device efficiency.
• • The contact layer exhibits excellent thermal stability: no significant chemical diffusion observed after one week of aging, ensuring long-term device reliability.
• • The single-leg device with Sn0.96Bi0.04Te0.98Se0.02 and Ni5.75SnTe5 contact layer achieves a maximum output power of ~0.02 W at ΔT~490 K, with conversion efficiency closely aligning with predictions from intrinsic material properties.
• • The contact layer selection strategy, guided by equilibrium thermodynamics, provides a design principle applicable to other thermoelectric materials, addressing the bottleneck of contact resistance and interdiffusion.