Experimental tuning of 2D heat conduction and thermoelectric conversion based on shape control

2019 Fiscal Year Final Research Report

• Project/Area Number: 18K13704
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 19020:Thermal engineering-related
• Research Institution: Kyushu University
• Principal Investigator: Li Qin-Yi 九州大学, 工学研究院, 助教 (60792041)
• Project Period (FY): 2018-04-01 – 2020-03-31
• Keywords: ナノスケール伝熱 / グラフェン / 熱伝導率 / 導電率 / ゼーベック係数 / 熱電性能指数 / 形状制御 / ナノ構造

Outline of Final Research Achievements

In this project, we designed a one-process approach for fabricating shape-tunable, high-quality graphene along with a new test device, which allows for simultaneous precise measurements of the thermal conductivity, electrical conductivity, and Seebeck coefficient. By adjusting the sample length and width, we measured largely reduced thermal conductivity and enhanced Seebeck coefficient while keeping high electrical conductivity. As a result, we obtained record-high thermoelectric figure of merit of graphene that is 2-4 orders of magnitude higher as compared to literature reports. The mechanisms behind the shape-tunable properties were clearly revealed by our physical simulations of quasi-particles.

Free Research Field

熱工学

Academic Significance and Societal Importance of the Research Achievements

非毒性かつ柔軟な2次元熱電材料は超スマートIoT社会のフレキシブルデバイスの電力供給源として注目されているが、熱電変換の効率はまだ非常に低いため大規模な展開は厳しく制限されている。本研究ではグラフェンの熱電性能指数を2～4桁向上させて、グラフェンが有望な柔軟熱電材料であることを示した。更に、２次元材料の熱と電気特性を前例のないレベルの別々にチューニングすることを実現して、熱科学の基礎研究に貢献できた。