Nanoporous graphene: A 2D semiconductor with anisotropic mechanical, optical and thermal conduction properties

Abstract

Nanoporous graphene (NPG), consisting of ordered arrays of nanopores separated by graphene nanoribbons was recently realized using a bottom-up synthesis method (Science 360(2018), 199). In this work we accordingly explored the mechanical response, thermal conductivity and electronic/optical properties of single-layer NPG using the density functional theory and molecular dynamics simulations. Along the armchair direction, NPG was found to exhibit higher tensile strength and thermal conductivity by factors of 1.6 and 2.3, respectively, in comparison with the zigzag direction. Despite of showing high rigidity and tensile strength, NPG was predicted to show around two orders of magnitude suppressed thermal conductivity than graphene. Results based on GGA/PBE highlight that NPG monolayer presents semiconducting electronic character with a direct band-gap of 0.68 eV. According to the HSE06 estimation, NPG monolayer shows a band-gap of 0.88 eV, very promising for the application in nanoelectronics. Optical results reveal that NPG nanomembranes can absorb the visible, IR and NIR light. This work highlights the outstanding physics of NPG, as a novel porous carbon based two-dimensional material, which may serve as a promising candidate to design advanced nanoelectronics, nanooptics and energy conversion systems.transitions. Some weak peaks are also observable between these two peaks, which are related to weak resonances. It is worthy to note that because of optical selection rules, only *    and *    transitions are allowed if the respectively, in the visible range of light. The first absorption peaks reveal that NPG nanomembranes can absorb the visible, IR and NIR light, suggesting their prospect for the applications in optoelectronics and nanoelectronics. The acquired results by extensive theoretical simulations provide a comprehensive vision concerning the critical properties of this novel nanoporous carbon based 2D semiconductor and will hopefully serve as a guide for the future theoretical and experimental studies. Acknowledgment B. M. and T. R.

Thermal conductivity and thermal rectification of nanoporous graphene: A molecular dynamics simulation

“…For comparison, the thermal conductivity of infinite graphene (709.2 / ) was calculated by this manner and the same potential in the previous work [30]. Also, this result is in agreement with the previous work [19]. As the last point of our study in this section, it is promising that the semiconductor NPG can be used as thermoelectric material because of its small thermal conductivity and get high performance for power generators [31].…”

“…As shown in the Fig. 3, the heat current that flows along the armchair direction of the NPG is greater than the zigzag direction [19].…”

“…This molecule shows inherent semiconducting character. [19] To employ the NPG in a practical situation, it needs to understand specifications and properties in a deep way. Thermal properties are the main issue in our current work that we study it in various conditions.…”

“…In the semiconductor and semimetals, the contribution of phonons in heat carriers is greater than the electrons that present in the system. According to the previous work [19] the NPG is a semiconductor so that we can ignore the electron contribution in the thermal conductivity [23]. In this work, all of NEMD simulations were performed using LAMMPS [24] package.…”

A Study on Phase and Microstructure of Reduced Graphene Oxide Prepared by Heating Corncobs

“…Microscopically, graphite consists of thin sheets resulting from bonds between carbon atoms called graphene [1]. Graphene is a developing material with a honeycomb-like two-dimensional crystal structure formed by carbon atoms at the sp2 hybrid junction, exhibiting unmatched electronic, thermal, and mechanical properties [2]. The most important problem for realizing graphene's potential is to achieve mass and controlled production [3].…”