Wang Xiaoming, Zebarjadi Mona, Esfarjani Keivan
Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio, 43606, United States.
Wright Center for Photovoltaic Innovation and Commercialization, The University of Toledo, Toledo, Ohio, 43606, United States.
Sci Rep. 2018 Jun 18;8(1):9303. doi: 10.1038/s41598-018-27430-0.
Two-dimensional (2D) van der Waals heterostructures (vdWHs) have shown multiple functionalities with great potential in electronics and photovoltaics. Here, we show their potential for solid-state thermionic energy conversion and demonstrate a designing strategy towards high-performance devices. We propose two promising thermionic devices, namely, the p-type Pt-G-WSe-G-Pt and n-type Sc-WSe-MoSe-WSe-Sc. We characterize the thermionic energy conversion performance of the latter using first-principles GW calculations combined with real space Green's function (GF) formalism. The optimal barrier height and high thermal resistance lead to an excellent performance. The proposed device is found to have a room temperature equivalent figure of merit of 1.2 which increases to 3 above 600 K. A high performance with cooling efficiency over 30% of the Carnot efficiency above 450 K is achieved. Our designing and characterization method can be used to pursue other potential thermionic devices based on vdWHs.
二维（2D）范德华异质结构（vdWHs）在电子学和光伏领域展现出多种功能且具有巨大潜力。在此，我们展示了它们在固态热电子能量转换方面的潜力，并论证了一种用于高性能器件的设计策略。我们提出了两种有前景的热电子器件，即p型Pt - G - WSe - G - Pt和n型Sc - WSe - MoSe - WSe - Sc。我们使用第一性原理GW计算结合实空间格林函数（GF）形式理论来表征后者的热电子能量转换性能。最佳的势垒高度和高耐热性带来了优异的性能。所提出的器件在室温下的等效品质因数为1.2，在600 K以上时增至3。在450 K以上实现了冷却效率超过卡诺效率30%的高性能。我们的设计和表征方法可用于探索基于vdWHs的其他潜在热电子器件。
