Designing good compatibility factor in segmented Bi0.5Sb1.5Te3 - GeTe thermoelectrics for high power conversion efficiency

Over the past decade, thermoelectrics have progressed in leaps and bounds led by advancements in their physical understanding and design. Figure of merit zT exceeding 2 have been consistently reported, especially in GeTe, one of the best medium-temperature thermoelectrics. However, its power conversion efficiency is limited due to its low performance at room temperature. In this work, we report the design and exploration of segmented thermoelectric legs by pairing GeTe with the best room temperature thermoelectric Bi0.5Sb1.5Te3 to achieve extremely high power conversion efficiency of 13.6% between 280 K and 773 K. The high efficiency is achieved by looking beyond simply combining high zT regions to encompass the thermoelectric compatibility factors between dissimilar materials. Our work opens up an avenue for materials design beyond maximizing zT to achieve technologically significant energy harvesting performance in thermoelectrics.

Automated summary

In the past decade, advancements in the understanding and design of thermoelectrics have led to significant progress. However, room temperature performance remains a bottleneck for thermoelectric power conversion efficiency. This study explores the design of segmented thermoelectric legs by pairing GeTe with the best room temperature thermoelectric, Bi0.5Sb1.5Te3, achieving a remarkably high power conversion efficiency between 280 K and 773 K. This high efficiency is achieved by considering the thermoelectric compatibility between different materials, opening up new possibilities for technologically significant energy harvesting performance in thermoelectrics.