Thermoelectric materials have been the focus of extensive research interest in recent years due to their potential in clean power generation from waste heat. Their conversion efficiency is primarily reflected by the dimensionless figure of merit, with higher values indicating better performance. There is a pressing need to discover materials that increase output power and improve performance, from the material level to device fabrication. This review provides a comprehensive analysis of recent advancements, such as Bi2Te3-based nanostructures that reduce thermal conductivity while maintaining electrical conductivity, GeTe-based high entropy alloys that utilize multiple elements for improved thermoelectric properties, porous metal-organic frameworks offering tunable structures, and organic/hybrid films that present low-cost, flexible solutions. Innovations in thermoelectric generator designs, such as asymmetrical geometries, segmented modules, and flexible devices, have further contributed to increased efficiency and output power. Together, these developments are paving the way for more effective thermoelectric technologies in sustainable energy generation.

1. Introduction
2. Thermoelectric Materials
    2.1. Bismuth telluride (Bi2Te3)-based TE Materials
    2.2. Germanium telluride (GeTe)-based TE materials
    2.3. Metal-organic frameworks (MOF)-based TE materials
    2.4. Organic polymers and composite TE materials
3. Thermoelectric device design andfabrication
    3.1. Asymmetrical geometry-based TEGs
    3.2. Segmented TEG Modules
    3.4 Flexible TEGs
4. Summary and Future Outlook
Funding
Conflict of Interest
Data Availability Statement
Author Information and Contribution
Acknowledgement
References

• Momanyi Amos Okirigiti(Department of Materials Science and Metallurgical Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 41566, Republic of Korea, Innovative Semiconductor Education and Research Center for Future Mobility, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 41566, Republic of Korea)
• Cheol Min Kim(Department of Materials Science and Metallurgical Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 41566, Republic of Korea, Innovative Semiconductor Education and Research Center for Future Mobility, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 41566, Republic of Korea)
• Hyejeong Choi(Department of Materials Science and Metallurgical Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 41566, Republic of Korea, Innovative Semiconductor Education and Research Center for Future Mobility, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 41566, Republic of Korea)
• Kwi-Il Park(Department of Materials Science and Metallurgical Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 41566, Republic of Korea, Innovative Semiconductor Education and Research Center for Future Mobility, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 41566, Republic of Korea, Research Institute of Automotive Parts and Materials, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 41566, Republic of Korea) Corresponding author
• Nagamalleswara Rao Alluri(Department of Materials Science and Metallurgical Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 41566, Republic of Korea, Research Institute of Automotive Parts and Materials, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 41566, Republic of Korea)