title: Thermionic Energy Conversion Based on Graphene van der Waals Heterostructures.
abstract: Seeking for thermoelectric (TE) materials with high figure of merit (or ZT), which can directly converts low-grade wasted heat (400 to 500 K) into electricity, has been a big challenge. Inspired by the concept of multilayer thermionic devices, we propose and design a solid-state thermionic devices (as a power generator or a refrigerator) in using van der Waals (vdW) heterostructure sandwiched between two graphene electrodes, to achieve high energy conversion efficiency in the temperature range of 400 to 500 K. The vdW heterostructure is composed of suitable multiple layers of transition metal dichalcogenides (TMDs), such as MoS2, MoSe2, WS2and WSe2. From our calculations, WSe2and MoSe2are identified as two ideal TMDs (using the reported experimental material's properties), which can harvest waste heat at 400 K with efficiencies about 7% to 8%. To our best knowledge, this design is the first in combining the advantages of graphene electrodes and TMDs to function as a thermionic-based device.
authors.affiliation: SUTD-MIT International Design Center (IDC), Singapore University of Technology and Design (SUTD), 8 Somapah road, 487372, Singapore.
authors.forename: Shi-Jun
authors.initials: SJ
authors.lastname: Liang
authors.affiliation: School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore.
authors.forename: Bo
authors.initials: B
authors.lastname: Liu
authors.affiliation: Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Hu
authors.affiliation: School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore.
authors.forename: Kun
authors.initials: K
authors.lastname: Zhou
authors.affiliation: SUTD-MIT International Design Center (IDC), Singapore University of Technology and Design (SUTD), 8 Somapah road, 487372, Singapore.
authors.forename: L K
authors.initials: LK
authors.lastname: Ang