2022-06-15 スウェーデン王国・王立工科大学（KTH)
熱電変換とは、熱を直接電気に変換することです。デバイスが発生する熱を捕らえ、同じデバイスや別のデバイスで使用できる電力に変換することが可能です。そのために必要なのが、特別に設計された熱電材料である。
熱電材料の一端を加熱すると、電荷キャリア（電子と正孔）が高温端から低温端に向かって移動し、電流が発生する。
室温動作のためのハイブリッド熱電材料の設計と開発に焦点を当てたもので、固体半導体をポリマーなどの柔軟な材料と統合し、インクを形成するものである。
このコーティングは熱を放出するあらゆる表面に適用でき、電力を発生させることができる。
＜関連情報＞
- https://www.kth.se/en/om/nyheter/centrala-nyheter/ink-coating-could-enable-devices-powered-by-heat-1.1176901
- https://pubs.acs.org/doi/10.1021/acsami.1c24392
オール溶液プロセスによる熱電変換インクとハイブリッド膜の力率調整機能 Thermoelectric Inks and Power Factor Tunability in Hybrid Films through All Solution Process
José F. Serrano-Claumarchirant, Bejan Hamawandi*, Adem B. Ergül, Andrés Cantarero, Clara M. Gómez, Pankaj Priyadarshi, Neophytos Neophytou, and Muhammet S. Toprak
ACS Applied Materials＆Interfaces Published:April 22, 2022
DOI:https://doi.org/10.1021/acsami.1c24392
Abstract
Thermoelectric (TE) materials can have a strong benefit to harvest thermal energy if they can be applied to large areas without losing their performance over time. One way of achieving large-area films is through hybrid materials, where a blend of TE materials with polymers can be applied as coating. Here, we present the development of all solution-processed TE ink and hybrid films with varying contents of TE Sb2Te3 and Bi2Te3 nanomaterials, along with their characterization. Using (1-methoxy-2-propyl) acetate (MPA) as the solvent and poly (methyl methacrylate) as the durable polymer, large-area homogeneous hybrid TE films have been fabricated. The conductivity and TE power factor improve with nanoparticle volume fraction, peaking around 60–70% solid material fill factor. For larger fill factors, the conductivity drops, possibly because of an increase in the interface resistance through interface defects and reduced connectivity between the platelets in the medium. The use of dodecanethiol (DDT) as an additive in the ink formulation enabled an improvement in the electrical conductivity through modification of interfaces and the compactness of the resultant films, leading to a 4–5 times increase in the power factor for both p- and n-type hybrid TE films, respectively. The observed trends were captured by combining percolation theory with analytical resistive theory, with the above assumption of increasing interface resistance and connectivity with polymer volume reduction. The results obtained on these hybrid films open a new low-cost route to produce and implement TE coatings on a large scale, which can be ideal for driving flexible, large-area energy scavenging technologies such as personal medical devices and the IoT.
