Synergistic Interface Design Enabling 16% Efficiency in Segmented GeTe Thermoelectric Modules

Abstract

The absence of suitable contact layers and reliable bonding processes severely restricts the long-term stability of GeTe-based thermoelectric generators for mid-temperature power generation. Here, TiTe₂ is screened as a suitable contact material based on phase-equilibrium analysis and diffusion-couple experiments. The TiTe₂/GeTe interface exhibits excellent chemical stability, thermal-expansion compatibility, and ohmic contact, thereby combining high mechanical strength with low electrical resistance. Using low-temperature transient liquid-phase bonding, the GeTe module can be fabricated at a low bonding temperature of 523 K while operating at temperatures up to 773 K. A module composed of p-type GeTe/Bi₂Te₃ segmented legs and n-type Mg3Sb2-based segmented legs is fabricated. A high conversion efficiency of ~16% is achieved under a temperature difference of 473 K, with no measurable degradation after 150 h of operation, demonstrating the long-term reliability of the TiTe₂/GeTe interface and transient liquid-phase bonding (TLPB) junctions. By integrating a rationally designed contact layer with a facile low- temperature bonding process, this work demonstrates the reliable fabrication of GeTe-based segmented modules and provides a viable approach for the development of high-performance thermoelectric generators.

Keywords

GeTe / Diffusion couple / Transient liquid phase bonding / Segmented module

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The Author(s) 2026. This article is published by Higher Education Press.

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