Jin Yingshi, Hwang Junphil, Han Mi-Kyung, Shon Wonhyuk, Rhyee Jong-Soo, Kim Sung-Jin
Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea.
Department of Applied Physics and Institute of Applied Sciences, Kyung Hee University, Yongin 17104, Korea.
ACS Appl Mater Interfaces. 2020 Aug 12;12(32):36589-36599. doi: 10.1021/acsami.0c08149. Epub 2020 Jul 30.
One promising approach to improving thermoelectric energy conversion is to use nanostructured interfaces that enhance Seebeck coefficient while reducing thermal conductivity. Here, we synthesized Au-CuSe core-shell nanoparticles with different shell thicknesses by controlling the precursor concentration in solution. The Au-CuSe core-shell nanoparticles are about 37-53 nm in size, and the cores of the nanostructures are composed of Au nanoparticles with sizes of ∼11 nm. The effect of shell thickness on the thermoelectric properties of core-shell nanocomposites is investigated after sintering the core-shell nanoparticles into pellets using the spark plasma sintering (SPS) technique. The power factor was optimized by the synergetic effect of the improvement of Seebeck coefficient by energy filtering in the Au/CuSe interface and the effective tuning of carrier concentration by Ohmic contact in the interface. The lattice thermal conductivity of core-shell nanocomposites is reduced by coherent phonon scattering, which is caused by the wavelike interference of phonons due to the phase shift in the core-shell interface. The highest value of 0.61 is obtained at 723 K for Au-CuSe core-shell nanocomposite with a shell thickness of 21 nm, which is higher than that of pure CuSe nanocomposite or a mixture of Au and CuSe particles.
一种改善热电能量转换的有前景的方法是使用纳米结构界面，该界面可提高塞贝克系数，同时降低热导率。在此，我们通过控制溶液中的前驱体浓度，合成了具有不同壳层厚度的金-硒化铜核壳纳米颗粒。金-硒化铜核壳纳米颗粒尺寸约为37-53纳米，纳米结构的核由尺寸约为11纳米的金纳米颗粒组成。在使用放电等离子烧结（SPS）技术将核壳纳米颗粒烧结成颗粒后，研究了壳层厚度对核壳纳米复合材料热电性能的影响。通过金/硒化铜界面中能量过滤对塞贝克系数的改善以及界面中欧姆接触对载流子浓度的有效调节的协同效应，优化了功率因数。核壳纳米复合材料的晶格热导率通过相干声子散射降低，这是由核壳界面中的相移导致的声子波状干涉引起的。对于壳层厚度为21纳米的金-硒化铜核壳纳米复合材料，在723K时获得了0.61的最高值，该值高于纯硒化铜纳米复合材料或金与硒化铜颗粒混合物的值。
