Challenging breaking thermoelectric performance limits by twistronics

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2023-06, Vol.11 (25), p.13519-13526
• Main Authors: Song, Jizhe, Sun, Mengtao
• Format: Article
• Language: English
• Subjects: Bilayers; Borophene; Cell size; Energy conversion; Figure of merit; Heat transfer; Phonons; Power factor; Silver; Thermal conductivity; Thermal energy; Thermoelectric materials
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d3ta02283h

With today's scarce resources, the issue of energy conversion is of great concern. Thermoelectric materials are capable of converting thermal energy to electrical energy. An excellent figure of merit ( ZT ) requires a high power factor and low thermal conductivity. Electron crystal-phonon glass materials can satisfy both these conditions. When phonon glass transforms into phonon liquid, it is of lower thermal conductivity and thus achieves a higher ZT . In this study, a twisted bilayer borophene (TBB) with a twist angle of 21.79° on a Ag(111) film is investigated. The bilayer borophene without twist angles has been synthesized experimentally [X. Liu, Q. Li, Q. Ruan, M. S. Rahn, B. I. Yakobson and M. C. Hersam, Nat. Mater. , 2022, 21 , 35-40]. The large cell size of 21.79° TBB creates favorable conditions for the short-range disordered phonon liquid state, which leads to a decrease in thermal conductivity and excellent ZT values. By taking advantage of the twist angle superlattice, the larger period leads to increased atomic short-range disorder, which can effectively reduce the thermal conductivity of bilayer borophene resulting in excellent ZT values.