An effective strategy for enhancing 2D graphene-like thermoelectric performance: Hydrogenation distortion

Abstract

Identifying the electronic origins of superior thermoelectric properties is crucial for designing and controlling new thermoelectric materials. In this work, we combined DFT calculations with Boltzmann's semiclassical transport theory to elucidate the general rules governing the thermal and electrical transport properties of hydrogenated graphene-like materials (2H-Graphenylene). Our results demonstrate that 2H-Graphenylene achieves a peak thermoelectric merit value of up to 1.66, surpassing most reported two-dimensional graphene-like materials. This superior performance is attributed to hydrogen atoms, which slow down phonon group velocity, reduce phonon relaxation time, and enhance the Grüneisen parameter. Simultaneously, hydrogenation transforms graphenylene into a topological material with nodal semimetals, increases its energy level degeneracy, and further reduces phonon propagation speed. This study presents novel strategies and foundations for regulating the thermoelectric properties of two-dimensional graphene-like materials.