Thermoelectric (TE) materials can convert temperature gradients into electricity and vice versa, playing a crucial role in NASA's deep space exploration since the 1970s. In recent years, TE has gained significant importance in applications such as sensing, powering small devices (including the Internet of Things and medical appliances), thermal management, and waste heat recovery for renewable energy technologies. The field of TEs is unique in its scientific nature as it involves the intricate interplay between thermal and electronic phenomena within materials.

To fully understand the TE properties of a material, a diverse range of techniques is required for comprehensive characterization. The TE community has encountered challenges in establishing uniform measurement methodologies and synthesis procedures, which hinder reliable performance comparisons across different laboratories. Addressing these inconsistencies is crucial for successfully transitioning novel TE materials from the laboratory to the market.

Optimizing the TE performance of materials requires careful adjustment of numerous, often conflicting parameters. Classically, this has included electronic and thermal transport properties as well as mechanical performance, but these are closely tied and controlled by crystallographic, compositional, and microstructural features. Consequently, a wide array of synthesis procedures has been developed, exploring diverse and innovative approaches to enhance TE performance.

This Topical Collection aims to foster transparency in synthesis and characterization processes, thereby reducing barriers to entry in TE research and enhancing the reproducibility of reported material properties. This collection invites authors to share their synthesis and characterization methodologies, facilitating the rigorous exploration of TE materials while advancing the understanding and reproducibility of measurement techniques.