Yan Lin, Luo Xuan, Yang RuiZhuang, Dai Fei, Zhu DongDong, Bai JunNan, Zhang Lin, Lei Haile
Research Center of Laser Fusion, China Academy of Engineering Physics, 621900 Mianyang, China.
ACS Appl Mater Interfaces. 2022 Aug 3;14(30):34562-34570. doi: 10.1021/acsami.2c05003. Epub 2022 Jul 23.
Due to its unique high conductivity and flexibility, the two-dimensional MXene material (TiCT) is expected to possess great potential in the thermoelectric field. However, the low thermoelectric performance from high thermal conductivity and a low Seebeck coefficient has limited its practical application. In this report, we demonstrate the uniform growth of ZnO layers on the laminar TiCT membrane by atomic layer deposition (ALD). Benefiting from the low-temperature deposition characteristics of the ALD technique, the ZnO@TiCT composite films maintain the basic apparent morphology of the original films after the deposition. We reveal that the Schottky barrier formed between ZnO and TiCT exhibits an energy-filtering effect, significantly enhancing the Seebeck coefficient to result in more than a double increase in the power factor. Meanwhile, the strong phonon-interface scattering between ZnO and TiCT is found to reduce the thermal conductivity of the composite films by a factor of four as compared to pure TiCT ones, further improving the overall thermoelectric properties of the ZnO@TiCT composite films. Our investigation provides an ALD-based strategy for growing wide band gap layers on the narrow band gap films to improve the thermoelectric performance of various MXene materials.
由于其独特的高导电性和柔韧性，二维MXene材料（TiCT）有望在热电领域具有巨大潜力。然而，高热导率和低塞贝克系数导致的低热电性能限制了其实际应用。在本报告中，我们通过原子层沉积（ALD）展示了ZnO层在层状TiCT膜上的均匀生长。受益于ALD技术的低温沉积特性，ZnO@TiCT复合薄膜在沉积后保持了原始薄膜的基本表观形态。我们发现，ZnO和TiCT之间形成的肖特基势垒表现出能量过滤效应，显著提高了塞贝克系数，使功率因数增加了一倍以上。同时，发现ZnO和TiCT之间强烈的声子界面散射使复合薄膜的热导率与纯TiCT薄膜相比降低了四倍，进一步提高了ZnO@TiCT复合薄膜的整体热电性能。我们的研究提供了一种基于ALD的策略，用于在窄带隙薄膜上生长宽带隙层，以提高各种MXene材料的热电性能。
