https://scholars.lib.ntu.edu.tw/handle/123456789/616363
標題: | Thermally Strain-Induced Band Gap Opening on Platinum Diselenide-Layered Films: A Promising Two-Dimensional Material with Excellent Thermoelectric Performance | 作者: | Su T.-Y. Chou T.-L. Chen L.-C. Chen K.-H. LI-CHYONG CHEN |
公開日期: | 2021 | 卷: | 33 | 期: | 10 | 起(迄)頁: | 3490-3498 | 來源出版物: | Chemistry of Materials | 摘要: | In this work, we, for the first time, observed the remarkable thermoelectric properties of a few high-quality PtSe2 layered films fabricated by a post selenization of Pt thin films. An excellent power factor of ∼200 μW/mK2 with a Seebeck coefficient of >100 μV/K in the PtSe2 layered film of 10 layers can be experimentally demonstrated over a wide temperature range, which is much better than those of most of the two-dimensional materials reported in the literature. Optical absorption spectra and DFT (density functional theory) calculations indicate a semiconductor-metal transition at a critical thickness once the thickness increases from 7.7 (15 layers) to 14.3 nm (30 Layers). The results are consistent with the experimental results of the dramatic reduction in the power factor, the magnitude of the Seebeck coefficient, and the resistivity when the thickness increases from 7.7 (15 layers) to 14.3 nm (30 Layers). Nevertheless, the semiconductor-metal transition would occur when the thickness increases from 1.5 nm (3 layers) to 2 nm (4 layers). To figure out this unusual performance, a detailed material examination has been conducted. After the transmission electron microscopy examination, ∼7% biaxial compressive strain built in the polycrystalline PtSe2 thin film can be observed. The strain, as revealed by our DFT calculations, plays an important role in opening the electronic energy gap and hence significantly improves the thermoelectric performance. Boltzmann transport calculation results suggested that both the strain and the hole concentration in the p-type specimens are well optimized. We further propose that an even better power factor can be achieved with n-type-doped PtSe2. © 2021 American Chemical Society. |
URI: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-85106475285&doi=10.1021%2facs.chemmater.0c04351&partnerID=40&md5=a8da40ea3820314dd327a7541960f0e5 https://scholars.lib.ntu.edu.tw/handle/123456789/616363 |
ISSN: | 08974756 | DOI: | 10.1021/acs.chemmater.0c04351 | SDG/關鍵字: | Density functional theory;Electric power factor;Energy gap;High resolution transmission electron microscopy;Light absorption;Platinum compounds;Seebeck coefficient;Selenium compounds;Thermoelectricity;Thin films;Biaxial compressive strain;Boltzmann transport calculations;Material examination;Semiconductor-metal transition;Thermoelectric performance;Thermoelectric properties;Two-dimensional materials;Wide temperature ranges;Potassium compounds |
顯示於: | 凝態科學研究中心 |
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