Exploring the enhancement of the thermoelectric properties of bilayer graphyne nanoribbons

Abstract

Carbon materials are vital for sustainable energy applications based on abundant and non-toxic raw materials. In this scenario, carbon nanoribbons have superior thermoelectric properties in comparison with their 2D material counterparts, owing to their particular electronic and transport properties. Therefore, we explore the electronic and thermoelectric properties of bilayer α-graphyne nanoribbons (α-BGyNRs) by means of density functional theory, tight-binding, and the non-equilibrium Green's functions (NEGF) method. Our calculations indicate that Ab stacking is the most stable configuration regardless of the edge type. The band structure presents finite band gaps with different features for armchair and zigzag nanoribbons. Concerning the thermoelectric quantities, the Seebeck coefficient is highly sensitive to the width and edge type, while its room-temperature values can achieve a measurable mV K⁻¹ scale. The electric conductance is found to increase due to layering, thus enhancing the power factor for α-BGyNRs compared with single nanoribbons. These findings therefore indicate the possibility of engineering such systems for thermal nanodevices.