Exceptional Performance of Room Temperature Sputtered Flexible Thermoelectric Thin Film Using High Target Utilisation Sputtering Technique

Publication status: PublishedAbstractThe High Target Utilisation Sputtering technique (HiTUS) is of interest for industrial processes, including in roll‐to‐roll manufacturing. This study marks the first application of HiTUS to thermoelectric materials, exemplified by bismuth telluride. The HiTUS technique separates the sputtering power into the plasma power and the target power, with additional kinetic energy in the sputtering particles from the applied electrical field, thus enabling a much wider sputter parameter space to modify the film performance. This study investigates how plasma power, target power, and substrate bias in HiTUS intricately influence crystal orientation/size, elemental composition, surface morphology, and other film properties. These factors subsequently affect carrier density/mobility, and consequently the thermoelectric performance of the bismuth telluride film. These deposited films reach a power factor of 6.5 × 10−4 W m−1 K−2 with a figure of merit ≈0.14 at room temperature, the highest value for room‐temperature sputtered un‐doped bismuth telluride. Subsequent post‐deposition annealing significantly enhances the crystallinity of the film (highly polycrystalline), further improving the power factor to 23.5 × 10−4 W m−1 K‐2, with a figure of merit ≈0.45 at room temperature. The excellent performance of the HiTUS fabricated thermoelectric film opens opportunities for the large‐area manufacture of thin‐film thermoelectric materials and devices.</jats:p

Roadmap on energy harvesting materials

Abstract Ambient energy harvesting has great potential to contribute to sustainable development and address growing environmental challenges. Converting waste energy from energy-intensive processes and systems (e.g. combustion engines and furnaces) is crucial to reducing their environmental impact and achieving net-zero emissions. Compact energy harvesters will also be key to powering the exponentially growing smart devices ecosystem that is part of the Internet of Things, thus enabling futuristic applications that can improve our quality of life (e.g. smart homes, smart cities, smart manufacturing, and smart healthcare). To achieve these goals, innovative materials are needed to efficiently convert ambient energy into electricity through various physical mechanisms, such as the photovoltaic effect, thermoelectricity, piezoelectricity, triboelectricity, and radiofrequency wireless power transfer. By bringing together the perspectives of experts in various types of energy harvesting materials, this Roadmap provides extensive insights into recent advances and present challenges in the field. Additionally, the Roadmap analyses the key performance metrics of these technologies in relation to their ultimate energy conversion limits. Building on these insights, the Roadmap outlines promising directions for future research to fully harness the potential of energy harvesting materials for green energy anytime, anywhere