Govt. College of Engineering & Textile Technology, Berhampore, WB, India.
Phys Chem Chem Phys. 2019 Nov 28;21(44):24758-24767. doi: 10.1039/c9cp04863d. Epub 2019 Nov 4.
A novel sp hybridized planar 2D carbon allotrope consisting of tetra, penta and octagonal (TPO) rings is proposed in this work. Its thermodynamic stability is confirmed by molecular dynamics in the canonical ensemble at 600 K and the analysis shows that it can also remain stable at 1000 K. The mechanical stability of this material has been estimated by the Born-Huang criterion. Its in-plane stiffness constants are found to be 85% of that of graphene ensuring its high strength quality. The investigation of the electronic properties reveals that the material is metallic in nature with a Dirac cone at 3.7 eV above its Fermi level at an asymmetric position in the conduction band. The study of its optical property for parallel and perpendicular polarization yields the absence of any plasma frequency. Besides, its absorption is mostly spread within 10-20 eV. Further electrical transport study shows negative differential resistance (NDR) above 3.5 V for one nano device. Nano ribbons made out of a TPO-graphene sheet exhibit metallic character. When the porous sheet of TPO-graphene is exposed to Li and S atoms, it is found that the Li atoms pass through the pores unlike the S atoms owing to the less barrier energy compared to S atoms. Substitutional doping with boron and nitrogen at different sites of TPO-graphene showed splitting of the Dirac feature. Also suitable B and N doping brings about semiconducting properties with tunability in band gap with a maximum band gap of 1.09 eV for an isoelectronic structure. All these theoretical predictions might trigger further new avenues involving this novel TPO graphene.
在这项工作中，提出了一种由四面体、五面体和八面体（TPO）环组成的新型 sp 杂化平面二维碳同素异形体。通过正则系综在 600 K 下的分子动力学证实了其热力学稳定性，分析表明它在 1000 K 下也能保持稳定。通过 Born-Huang 判据估计了这种材料的机械稳定性。发现其面内弹性常数为石墨烯的 85%，确保了其高强度质量。对电子特性的研究表明，该材料本质上是金属的，在导带的非对称位置，费米能级上方 3.7 eV 处有一个狄拉克锥。对平行和垂直偏振的光学性质的研究表明，不存在任何等离子体频率。此外，其吸收主要分布在 10-20 eV 范围内。进一步的电输运研究表明，对于一个纳米器件，在 3.5 V 以上存在负微分电阻（NDR）。由 TPO-石墨烯片制成的纳米带表现出金属特性。当 TPO-石墨烯的多孔片暴露于 Li 和 S 原子时，发现与 S 原子相比，Li 原子由于比 S 原子的势垒能量小而穿过孔。在 TPO-石墨烯的不同位置用硼和氮进行取代掺杂会导致狄拉克特征的分裂。此外，适当的 B 和 N 掺杂会带来半导体性质，并可通过带隙调谐实现，对于等电子结构，最大带隙为 1.09 eV。所有这些理论预测可能会引发涉及这种新型 TPO 石墨烯的新途径。
