Effects of IIIA element doping on structure stability, electronic structure and optical properties of T-carbon
Introduction
It is well known that there are three natural allotropes of carbon, called as graphite, diamond, and amorphous carbon. Their properties are very different. In the past few decades, carbon has been used to synthesize several different substances with excellent properties, such as fullerenes, carbon nanotubes, and two-dimensional graphene. This makes it possible to synthesize new carbon allotropes.
In 2011, Chen et al. predicted that T-carbon with a diamond structure would make research on new lithium battery materials possible [1]. T-carbon is obtained by replacing carbon atoms in the cubic diamond structure with carbon tetrahedrons. The space group of T-carbon is Fd3m, the lattice constant is 7.52 Å, which is more than twice that of diamond (3.566 Å). Compared with diamond, T-carbon has two types, tetrahedral bonds and intertetrahedral bonds, which are 1.502 Å and 1.417 Å, respectively. The density is 1.50 g cm−3, which is much smaller than diamond and graphite. T-carbon has a Vickers hardness of 61.1 GPa, which is about a third softer than diamond (96 GPa). The above results are only theoretical predictions, and there is no experimental evidence. Until 2017, Zhang et al. prepared T-carbon through experiments, which set off a wave of T-carbon research [2]. Except for the slightly different lattice constants (7.80 Å in experiment), other properties such as hardness, band gap, elasticity, etc. are highly consistent with the prediction. Sun et al. studied the optical properties of T-carbon and found that T-carbon is a semiconductor with a direct band gap (GGA: 2.25 eV; HSE06: 2.273 eV; B3LYP: 2.968 eV), and the energy level in the conduction band is smaller than that of perovskite structure by 0.5 eV. In addition, the calculated electron mobility can reach 2.36 × 103 cm2s−1V−1, which is superior to conventional electron transport materials, such as TiO2, ZnO and SnO2 [3]. Moreover, the research group also studied the mechanical behavior and structural evolution of T-carbon nanowires under tension through molecular dynamics, and found that T-carbon nanowires exhibit excellent mechanical properties, such as anisotropy, and excellent ductility [4]. Recently, T-carbon was synthesized experimentally from pseudo-topological conversion of multi-walled carbon nanotubes (MW CNTs) suspended in methanol under picosecond pulsed laser irradiation. It is proved that T carbon nanowires have better ductility and larger failure strain than other carbon materials such as diamond and diamond-like carbon [5]. At the same time, research on T-carbon doping is also underway. Hao et al. studied the effect of single doping on system stability and band gap [6]. Hamidreza Alborznia et al. studied the effect of single doping at high pressure on the electronic and optical properties of the system [7]. The above research shows T-carbon and its doping system have excellent electrochemical properties.
However, because T carbon is a new type of material, the research focuses on the basic properties of T-carbon, and there are few explorations on its modification. In order to explore the new direction of the application of T-carbon modified materials, in this present contribution, by combining first-principles calculations, the electronic structures and optical properties of bulk T-carbon as well as doping systems are systematically investigated. First of all, by calculating the electronic properties of intrinsic T-carbon by using different functionality, the insensitivity to the selection of functionality has been shown. Then the effects of different elements doping in different positions on the electronic and optical properties are studied in detail.
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Computational method and models
The present calculations are performed within the framework of density functional theory (DFT) in the CASTEP package and used the general gradient approximation (GGA) with Perdew-Burke-Ernzerhof (PBE) version for the exchange–correlation energies [8], [9]. The central electron–ion interactions are described using ultra-soft pseudopotential. The method that reduces the effect of van der Waals (vdW) interaction is dispersion-corrected DFT (DFT-D). In the calculation we used 400 eV as the
Optimization results of doped T-carbon
The lattice constants of the systems after and before doping are calculated and then shown in Table 1. The stability of the B-doping system is indirectly proven due to the low volume expansion rate of no more than 1%. However, Al-doping will cause large lattice distortion, which is not conducive to the stability of the system.
For T-Carbon, the formation energy is an important parameter and represents the stability of the material. The smaller the formation energy is, the more stable the
Conclusion
In this present contribution, the first-principle calculations based on density functional theory are conducted to investigate the effects of substitution on the performance in T-carbon. The effective mass of intrinsic T-carbon electrons is far less than 1.5 m0, indicating that its electron migration rate is extremely high compared to other intrinsic semiconductors. The mh*/me* means that it is difficult for electrons and holes to match, which is conducive to the improvement of its
CRediT authorship contribution statement
Xuefeng Lu: Conceptualization, Writing - review & editing. Zhihong Cui: Data curation, Formal analysis, Writing - original draft. Xin Guo: Investigation, Project administration. Junqiang Ren: Resources, Software. Hongtao Xue: Visualization, Validation. Junchen Li: Supervision. Fuling Tang: Project administration.
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
The work was supported by the National Natural Science Foundation of China (Grant No. 51662026), Graduate Research Exploration Project, Joint fund between Shenyang National Laboratory for Materials Science and State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals (Grant No. 18LHPY001), the open fund of the State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals (SKLAB02019011).
References (22)
- et al.
Nat. Commun.
(2017) - et al.
Carbon
(2018) - et al.
Carbon
(2020) - et al.
Optik.
(2019) - et al.
Comp. Mater. Sci.
(2018) - et al.
Comp. Mater. Sci.
(2019) - et al.
Ann. Phys.-Berlin.
(2017) - et al.
Phys. Rev. B.
(2011) - P.P. Sun, L.C. Bai, D.R. Kripalani, K. Zhou, Comp. Mater. Sci. 5 (2019) 9....
- et al.
Chem. Phys.
(2019)
Phys. Rev. B.
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