Optical excitations and thermoelectric properties of two-dimensional holey graphene

Abstract

Recently, holey graphene (HG) was synthesized successfully at atomic precision with regard to hole size and shape, which indicates that HG has interesting physical and chemical properties for energy and environmental applications. The shaping of the pores also transforms semimetallic graphene into semiconductor HG, which opens new doors for its use in electronic applications. We investigated systematically the structural, electronic, optical, and thermoelectric properties of HG structure using first-principles calculations. HG was found to have a direct band gap of 0.65 eV (PBE functional) and 0.95 eV (HSE06 functional); the HSE06 functional is in good agreement with experimental results. For the optical properties, we used single-shot G 0 W 0 calculations by solving the Bethe-Salpeter equation to determine the intralayer excitonic effects. From the absorption spectrum, we obtained an optical gap of 1.28 eV and a weak excitonic binding energy of 80 meV. We found large values of thermopower of 1662.59 μV/K and a better electronic figure of merit, ZT e , of 1.13 from the investigated thermoelectric properties. Our investigations exhibit strong and broad optical absorption in the visible light region, which makes monolayer HG a promising candidate for optoelectronic and thermoelectric applications.

An ab initio Study of Structural, Electronic and Optical Properties of Janus AlInS2 homo-bilayer

“…To calculate the dielectric constant, we used the real (𝜀 1 ) and imaginary (𝜀 2 ) part, 𝜀(𝜔) = 𝜀 1 (𝜔) + 𝑖𝜀 2 (𝜔) [21,22]. The real part can be used to understand the polarizability of the material by using the Clausis-Mossoti relation [23] while the imaginary part is used to analyze the electronic band structure of the material. The real part is shown in Fig.…”

Dimensionality effects in high‐performance thermoelectric materials: Computational and experimental progress in energy harvesting applications

“…32 Some other investigations also suggest that the LD materials improved the TE performance. 108,[156][157][158][159][160][161][162][163][164][165][166] The lists of novel LD TE materials for high TE performance are summarized in Table 2. From these results, the nanostructures significantly improved the performance of TE materials.…”

Stability of and conduction in single-walled Si$_2$BN nanotubes

“…Low dimensional material research has produced exciting results by combining computational predictions, experimental synthesis, and characterization [1]. The immense interest in low dimensional materials is fueled by alluring properties and a broad range of potential applications, such as quantum computing, batteries, electrocatalysis, photovoltaics, electronics, bio-medicals, and photonics [2][3][4][5][6][7][8]. There exists a broad range of two-dimensional (2D), one-dimensional (1D), and even dot-like structures.…”