Modulating Thermoelectricity in Bilayer Graphene Nanoribbons Via Light Irradiation

Thermoelectric materials which convert thermal energy into electrical energy and vice versa, hold significant promise for sustainable energy technologies and waste heat recovery [1-2]. The efficiency of these materials is quantified by the dimensionless figure of merit ZT, which depends on the Seebeck coefficient, electrical conductivity, and thermal conductivity. Materials with a ZT &lt; 1 are usually deemed inefficient for real-world uses whereas those with a ZT &gt; 1 are seen as having strong thermoelectric performance. The goal generally is to reach a ZT &gt; 2 for commercially feasible solutions. This has spurred significant research efforts into enhancing thermoelectric efficiency through new materials and structural innovations, as achieving high ZT can lead to better performance in power generation technologies [3-5].<br/>We will present our investigation on utilizing bilayer graphene (BLG) for thermoelectric applications by irradiating it with light to reduce thermal conductivity while preserving its excellent electrical properties. We will utilize ultrasoft pseudopotentials in the local density approximation using the Perdew, Burke, and Ernzerhof (PBE) [6] functional to obtain the structural and phonon transport properties of the AA- and AB-stacked bilayer graphene. The van der Waals interactions, which play a crucial role in bilayer graphene, were accounted for using the Grimme D3 method [7]. By exposing BLG to light, we induce anisotropy and modify the electron and phonon interactions within the material. We provides a detailed analysis of the electron and phonon spectra of thermoelectric quantities, atomic vibration modes, phonon group velocity, and Gr{\"u}neisen parameters. This approach opens up new possibilities for optimizing the performance of thermoelectric devices using bilayer graphene.<br/><br/>References:<br/>[1]. Xu Y, Li Z, Duan W. Thermal and thermoelectric properties of graphene. Small 10.11 (2014)<br/>[2] Amollo, T. A., Mola, G. T., Kirui, M. S. K., and Nyamori, V. O. (2018). Graphene for thermoelectric applications: prospects and challenges, Critical Reviews in Solid State and Materials Sciences, 432, 133-157<br/>[3] Chen S, Wu Q, Mishra C, Kang J, Zhang H, Cho K, Cai W, Balandin A A and Ruoff R S Thermal conductivity of isotopically modified graphene. Nature Mater 11, 203–207 (2012)<br/>[4] Hao F, Fang D and Xu Z. Mechanical and thermal transport properties of graphene with defects. Applied physics letters 99, no. 4 (2011).<br/>[5] WangC, LiuY, Li L and Tan H 2014 Anisotropic thermal conductivity of graphene wrinkles. Nanoscale 6, no. 11 (2014): 5703-5707<br/>[6] Perdew, J. P, Burke, K, Ernzerhof, M. Generalized Gradient Approximation Made Simple. Phys. Rev. Lett. 1996, 77, 3865–3868.<br/>7] Chiter, F., Nguyen, V. B., Tarrat, N., Benoit, M., Tang, H., Lacaze-Dufaure, C. Effect of van der Waals Corrections on DFT-Computed Metallic Surface Properties. Mater. Res. Express 2016, 3, 046501.