Abstract

The family of graphynes, novel two-dimensional semiconductors with various and fascinating chemical and physical properties, has attracted great interest from both scientific and industrial communities. Currently, the focus is on graphdiyne or graphyne-2. In this work, we systematically study the effect of acetylene, i.e., carbon–carbon triple bond, links on the electronic and optical properties of a series of graphynes (graphyne-n, where n = 1–5, the number of acetylene bonds) using ab initio calculations. We find an even–odd pattern, i.e., n = 1, 3, 5 and n = 2, 4 having different features, which has not been discovered in studying graphyne or graphdiyne alone. It is found that as the number of acetylene bonds increases, the electron effective mass increases continuously in the low-energy range because of the flatter conduction band induced by the longer acetylene links. Meanwhile, longer acetylene links result in a larger red shift of the imaginary part of the dielectric function, loss function, and extinction coefficient. In this work, we propose an effective method to tune and manipulate both the electronic and optical properties of graphynes for the applications in optoelectronic devices and photochemical catalysis.
1. Introduction
The large variety of carbon allotropes, showing different physical and chemical properties, is due to the different carbon hybridizations, i.e., sp, sp2, and sp3. For example, the natural three-dimensional (3D) graphite and diamond are formed through sp2 and sp3 hybridizations of carbon atoms, respectively. Meanwhile, the sp2 hybridization occurs in some novel man-made carbon allotropes, such as fullerene,1 carbon nanotube,2 and graphene.3 In 1987, the concept of sp–sp2 hybridized graphyne-n was theoretically proposed by Baughman,4 where n indicated the number of carbon–carbon triple (acetylene) bonds in graphyne (see Figure 1). Accordingly, there are several kinds of structures based on the polymerization mode, such as graphyne (n = 1), graphdiyne (n = 2), graphyne-3 (n = 3), and so on. After the successful synthesis of graphyne (n = 1) in the experiment, it has been of particular interest due to its unique semiconducting electronic structure and extensive applications in many fields, such as catalysis, sensor and transistor technologies, and energy storage (see reviews5,6 and references therein). Simultaneously, engineering of tuning the electronic structure by simply constructing the acetylene bonds n has been attracted more and more attention to this kind of two-dimensional (2D) materials theoretically and experimentally.
Figure 1.
Optimized geometric structures of unit cells of 2D graphynes. Each graphyne is named with an index “n”, which indicates the number of carbon–carbon triple bonds in a link, highlighted in red, between two adjacent hexagons: (a) graphyne-1, (b) graphyne-2, (c) graphyne-3, (d) graphyne-4, and (e) graphyne-5.
Recently, 2D semiconducting graphyne-2 has been synthesized on a copper surface by the cross-coupling reaction.7−9 Soon, these types of 2D materials attracted great attention in many research fields, such as catalysis, energy storage, water purification, and optoelectronic devices, due to their large interlayer distance, unique porous structure, large specific surface area, and high conductivity.10−19 Theoretical calculations reveal that graphyne-2 has higher electron mobility than graphene.20,21 Kuang et al.22 further pointed out that the electron mobility and photoconversion efficiency of perovskite solar cells with doped graphyne-2 were significantly improved, which paves the way for optoelectronic applications of graphyne-2. Wang et al.17 synthesized graphyne-2 composites by the hydrothermal method, which exhibited excellent photocatalytic degradation of methylene blue. The π-conjugated structure in graphyne-2 makes it efficient to receive photogenerated electrons in the conduction band and to suppress the recombination of electrons and holes. Luo et al.23 found that the multibody effect had a significant impact on the electronic structure and optical absorption of graphyne-2 both theoretically and experimentally. Due to the additional acetylene bond in graphyne-2 compared with graphyne-1, graphyne-2 has a larger porous and much softer structure than graphyne-1, which indicates that graphdiyne could easily form a hybrid with other materials for optical applications.5,6 The difference in the electronic structures and mechanical properties between graphyne and graphdiyne as well as the resulting different potential applications has accelerated the engineering and application of the graphyne-n family, especially in the properties of graphyne-n with longer acetylene links beyond n = 1 and 2.
In this paper, the electronic and optical properties of five members in the graphyne family, i.e., graphyne-n (n = 1–5), are systemically investigated using ab initio calculations. It was found that the length of the acetylene links greatly changes the feature of the energy bands near the Fermi level. Thus, both the electronic and optical properties of these types of 2D materials could be feasibly tuned and manipulated for optoelectronic devices and photochemical catalysis applications. This may open a way for exploring the extended graphynes in optoelectronic applications.
2. Computational Methods
In this work, we carried out ab initio calculations with the CASTEP module,24 which was implemented in the framework of density functional theory (DFT)25 using the generalized gradient approximation (GGA) in the parameterization of the Perdew–Burke–Ernzerhof (PBE) format exchange–correlation functional.26 The Grimme27 under dispersion correction (DFT-D) was used to improve the calculation accuracy of the weak interaction in 2D graphynes. The electron–ion interactions were described by the Vanderbilt ultrasoft pseudopotentials (US-PP).26 The convergence test and geometric optimization of the graphyne-n unit cell were performed first. The kinetic cutoff energy used for plane wave expansions was 650 eV. For graphyne-1, graphyne-2, and graphyne-3, the Monkhorst–Pack K-point meshes of 11 × 11 × 1 were used in the first Brillouin zone,28 while for graphyne-4 and graphyne-5 with large unit cells, the Brillouin zone integrations were performed using a Monkhorst–Pack grid of 8 × 8 × 1. The vacuum layer thickness was set to 15 Å to eliminate the interlayer interaction. Each calculation was converged when the total energy changes during the geometry optimization process were less than 1 × 10–5 eV/atom, and the force per atom and the residual stress of the unit cell were less than 0.01 eV/Å and 0.05 GPa, respectively. The maximum displacement between cycles was less than 0.005 Å when the convergence reached.
3. Results and Discussion
3.1. Geometric Structures
The geometric structures of the unit cells of graphyne-1, graphyne-2, graphyne-3, graphyne-4, and graphyne-5 are shown in Figure 1. The size of the cavity of graphynes is proportional to the length of the acetylene linkages. The structural stability of graphynes can be estimated by the cohesive energy, which can be defined as follows.29
| 1 |
where Ecoh is the cohesive energy of graphynes, n is the number of carbon atoms in a unit cell, and Eatom and Etotal are the energy of a single carbon atom and the total energy in a unit cell, respectively. The details of the lattice constant, cohesive energy, and comparison with other reports are shown in Table 1. As can be seen, the calculated lattice parameters in this work are in good agreement with previously reported works. Our cohesive energies are slightly higher than other results, which might be due to the different pseudopotentials used.
Table 1. Lattice Constants and Cohesive Energies of Graphynes.
| graphyne | graphdiyne | graphyne-3 | graphyne-4 | graphyne-5 | ||
|---|---|---|---|---|---|---|
| lattice constant (Å) | this work | 6.872 | 9.436 | 12.011 | 14.576 | 17.592 |
| other works | 6.86a, 6.877b, 6.89c | 9.44a, 9.46c, 9.490c | 12.02a, 12.04c, 12.43d | 14.6a, 14.60c | ||
| cohesive energy (eV atom–1) | this work | 8.635 | 8.513 | 8.450 | 8.419 | 8.397 |
| other works | 7.95a, 7.21e | 7.78a, 7.87e | 7.70a | 7.66a |
It is noted that the cohesive energy is the energy required for separating the neutral atoms in the ground state at 0 K.30 Thus, the larger the Ecoh, the more stable the crystal structure. According to the calculated cohesive energies in Table 1, it can be found that the planar two-dimensional structure of graphyne-1 is the most stable. Meanwhile, the cohesive energy of graphynes decreases gradually with the increase of the number of acetylene bonds (n).
3.2. Electronic Properties
Figure 2 shows the band structures of graphynes. It can be seen that all of them are direct-band-gap (Eg) semiconductors with band gaps of 0.446, 0.464, 0.548, 0.524, and 0.544 eV. It is worth noting that the band gap size is not simply linearly proportional to the number of acetylene bonds (n). Interestingly, the direct band gap of graphyne-n with odd n, i.e., n = 1, 3, 5, is located at the M-point, while it is at the Γ-point for even n. Meanwhile, the energy-band dispersions at the bottom of the conduction band and at the top of the valence band are quite similar for all graphynes, which indicates that they have similar effective mass of both electrons and holes.
Figure 2.
Energy-band structures of graphyne-n. Eg is the direct band gap. A and B indicate the possible electron excitation, hopping from the valence band to the conduction band.
The effective mass of electrons and holes in semiconductors is an essential parameter, which greatly affects the performance of electronic and/or optical devices. The effective mass of graphynes is calculated by the following equation.35
| 2 |
The values of the effective mass in the conduction band (mc, holes) and valence band (mv, electrons) are listed in Table 2. It is found that the effective mass is isotropic from M to K and Γ for graphyne-n with even (n = 2, 4) acetylene bonds, while it is anisotropic if n is odd. Our calculations show that the low energy levels of the conduction band are mainly contributed by the 2p state of carbon atoms, where the electrons have quite a small effective mass under the excitation of photons. This indicates that it facilitates the formation of the effective photogenerated electrons and the transferred charge carriers, while more effective photogenerated holes would be formed in the valence-band region.
Table 2. Values of the Effective Mass of Graphynes in the Conduction (mc) and Valence Band (mv) and the Band Gap (Eg).
|
mc/m0 |
mv/m0 |
||||
|---|---|---|---|---|---|
| structure | Γ → M | M ← K | Γ → M | M ← K | Eg (eV) |
| graphyne-1 | 0.146(0.15a, 0.21b) | 0.086(0.063a, 0.087b) | 0.150(0.17a, 0.22b) | 0.068(0.066a, 0.0901b) | 0.446 at M (0.46c,0.47d,e) |
| graphyne-2 | 0.080(0.073a) | 0.074(0.075) | 0.464 at Γ (0.48,0.46f,) | ||
| graphyne-3 | 0.082(0.099a) | 0.053(0.081a) | 0.106(0.12a) | 0.081(0.085a) | 0.548 at M (0.56d) |
| graphyne-4 | 0.078(0.081a) | 0.110(0.080) | 0.524 at Γ (0.54d) | ||
| graphyne-5 | 0.101 | 0.091 | 0.133 | 0.120 | 0.544 at M |
It is found that all graphynes have covalent bonds from the Mulliken population (MP) analysis (Table S1), implying their good structural stability. Moreover, the MP analysis shows that the electronic states of graphynes are mainly contributed by the C-2p state, which is consistent with the projected density of state (PDOS) analysis shown in Figure S1. The bond lengths and band populations of C1–C2 (sp2–sp2), C2–C3 (sp2–sp), C4–C5 (sp–sp), and C6–C7 (sp–sp) bonds of graphynes (see Figure 1) remain constant with the increase of the number of acetylene bonds (n). However, the bond lengths (band populations) of C3–C4, C5–C6, and C7–C8 (sp≡sp) bonds (Figure 1) are enlarged as n increases. These alternate bonding characteristics are also illustrated by the charge-density-difference calculations as shown in Figure S2. Such an alternate −C≡C–C≡C– structure can energetically stabilize atomic carbon chains or rings, which have been reported in many carbon allotropes.40,41
3.3. Optical Properties
The calculated band structures of graphynes in Figure 2 show that they all are direct-band-gap semiconductors, and the values of band gaps are close to those of silicon (0.57 eV GGA-PBE42). Thus, we next study the optical properties of graphynes and their potential optoelectronic applications. It is well-known that standard GGA functionals like PBE underestimate the band gap. One of the major improvements in the band gap calculation is to use the hybrid functionals, such as HSE06.43 However, both GGA-PBE and HSE06 give similar spectra except for an energy shift of graphynes,44 so only GGA-PBE results are presented in this work.
The complex dielectric function ε(ω), a significant parameter to determine the polarization effect inside materials, is calculated as
| 3 |
where the imaginary part of the dielectric function ε2(ω) describes the absorption of light and the real part of the dielectric function ε1(ω) represents the amplitude modulation, that is, the resonant absorption of the electron transition.45
| 4 |
| 5 |
| 6 |
| 7 |
| 8 |
| 9 |
| 10 |
where m is the free electron mass, e is the free electric charge, ω is the incident photon frequency, BZ is the first Brillouin zone, |e·MCV(K)| is the momentum transition matrix element, K is the inverted lattice vector, k is the extinction coefficient, C is the conduction band, V is the valence band, and EC(K) and EV(K) are the intrinsic levels of the conduction and valence bands. Meanwhile, the absorption coefficient I(ω), conductivity σ(ω), refractive index n(ω), loss function L(ω), and reflectivity R(ω) can all be deduced from ε(ω) with the Kramers–Kronig dispersion.46−48
Figure 3 shows the calculated imaginary and real parts of the complex dielectric function, absorption function, and electrical conductivity of graphynes. The peak position of ε2(ω) is determined by the band gap and the degree of nonlocalization in the low-energy regions. With the increase of the number of acetylene bonds, ε2(ω) of graphynes has red-shifted as shown in Figure 3a. For the real part of the dielectric function ε1(ω), the static dielectric constant (capacitance) is denoted ε1(0) at the zero frequency. The ε1(0) of graphynes is strongly dependent on the corresponding band gaps as shown in Table 3. Our results in Figure 3b show that ε1(ω) dramatically decays to zero with the increase of the photon energies, indicating a resonance of the energy transition between electrons and photons in graphynes. Figure 3b shows that ε1(ω) of graphyne-2–5 has negative values (positive for graphyne-1). According to the wave vector equation below
| 11 |
ε1 < 0 means that the wave vector K is an imaginary number. Furthermore, this negative value region is red-shifted with the increase of the number of acetylene bonds (n) as shown in Figure 3b.
Figure 3.

(a) Imaginary and (b) real parts of complex dielectric functions of graphynes. (c) Absorption function and (d) electrical conductivity of graphynes. The visible light region is labeled by two vertical dotted lines. The low-energy part is enlarged in the insets.
Table 3. Energy Corresponding to the Peak of the Imaginary Part of the Dielectric Function ε2(ω), Energy of Electron Interband Transition, Static Dielectric Constant ε1(0), and Absorption Edges Eop of Graphynes.
| structure | photon energy (eV) | transition (eV) | ε1 (0) | Eop (eV) |
|---|---|---|---|---|
| graphyne | A = 0.9 | –0.20 → 0.70 | 12.9 | 5.37 |
| B = 6.1 | –2.07 → 4.03 | |||
| graphdiyne | A = 1.2 | –0.36 → 0.84 | 10.3 | 3.57 |
| B = 4.1 | –2.64 → 1.46 | |||
| graphyne-3 | A = 1.0 | –0.21 → 0.79 | 8.9 | 2.65 |
| B = 3.0 | –1.10 → 1.90 | |||
| graphyne-4 | A = 1.1 | –0.27 → 0.84 | 9.6 | 2.15 |
| B = 2.4 | –0.80 → 1.60 | |||
| graphyne-5 | A = 1.1 | –0.25 → 0.85 | 8.9 | 1.79 |
Figure 3c shows that the absorption coefficient in graphynes increases first and consequently decreases as the photon energy goes up. The peak of the absorption coefficient of graphynes shifts to the low-energy region and induces a narrow absorption range. Further analysis on the absorption function of graphyne-1 (Figure 3c) shows that there are four main absorption peaks at 1.95, 2.96, 6.63, and 12.03 eV, which are well consistent with the experimental values.23 For graphyne-2 and graphyne-3, the highest peak is located within the ultraviolet region. Thus, they probably may have applications in ultraviolet protection or detection materials. The shift of the photoconductivity of graphynes with the photon energy is shown in Figure 3d. The conductivity peaks of graphyne-1 are at 1.46, 2.59, 6.24, and 11.97 eV. The profiles of the photoconductivity of graphynes shift to the low-energy region (Figure 3d), which approaches the energy range of the visible light.
The peak energy of the dielectric function ε2(ω), energy of electron interband transition, static dielectric constant ε1(0), and absorption edges are presented in Table 3. For graphyne-1, the primary peaks of ε2(ω) are located at A (0.9 eV) and B (6.1 eV). Based on the band structure in Figure 2, peak A mainly originates due to the transition between the unoccupied states at 0.70 eV and the occupied states at −0.20 eV. Meanwhile, peak B primarily originates from the transition from −2.07 to 4.03 eV of the 2p electrons in the valence band of the C atoms. The details of transitions of two peaks in ε2(ω) of graphyne-2, graphyne-3, and graphyne-4 are summarized in Table 3. For graphyne-5, it is worth noting that the imaginary part of the dielectric function ε2(ω) gives rise to a bimodal pattern, which shows only one peak at 1.1 eV due to the band localization and red shift of the functional profile (see in Figure 3). Furthermore, the transition between the occupied state at −0.25 eV and the empty state at 0.85 eV corresponds to peak A. Note that the peak in the imaginary part of the dielectric function ε2(ω) may not correspond to a single interband transition (Figure 2), and other interband transitions at the same peak energy may also possibly occur in the band structure.49,50
The optical absorption edges of graphynes are shown in Figure 4. The optical absorption band edge Eop is described by the following extrapolation relationship51
| 12 |
where α represents the absorption spectrum, hν is the photon energy, and A is a function of the refractive index of the material, the reduced mass, and the speed of light in vacuum. For direct-band-gap semiconductors, n takes 0.5.
Figure 4.
Optical absorption edges of graphynes, with the enlarged view shown in the inset.
The calculated values of the optical absorption band edge in graphyne-n are listed in Table 3. It is found that the absorption band edge shifts to the low-energy region with the increase of n. Moreover, there is a deviation between the absorption band edge and the corresponding band gap. It is mainly due to the electron localization in the free energy level of band structures.
The relationship between the complex refractive index n(ω) and extinction coefficient k(ω) with the photon energy of graphynes is shown in Figure 5a,b. At a frequency of zero, the static refractive indices of graphyne-n (n = 1–5) are located at 3.61, 3.22, 3.00, 3.01, and 2.99 eV, respectively. This indicates that the static index of refraction strongly depends on the band gap of graphynes. Furthermore, the complex refractive index of graphynes goes down first and then increases with an increase of the photon energy. The graphynes have distinct peaks of the energy loss in the calculated profile, as shown in Figure 5c. They correspond to the region of ε1(ω) = 0 and ε2(ω) < 0, which are the resonance peaks of the energy loss function in graphynes. The reflection spectrum of graphynes is shown in Figure 5d. Our results show that the reflectivity R(0) of graphyne-1 approaches 32.2 and diminishes with the increase of the photon energy. The maximum value is 12.4% at a photon energy of 7.20 eV. Furthermore, as the acetylene bonds (n) increase, the profiles of the energy loss function shift to the low-energy region, and the electron localization and maximum values are enhanced (Figure S3).
Figure 5.

(a) Real and (b) imaginary parts of the complex refractive index of graphynes. (c) Loss function and (d) reflectivity of graphynes. The visible light region is labeled by two vertical dotted lines. The low-energy part is enlarged in the insets of (a) and (b).
Conclusions
In summary, we carried out ab initio studies on the geometric, electronic, and optical properties of 2D graphyne-n sheets, a family of sp–sp2 hybrid materials with acetylene bonds. The odd–even pattern of n of graphynes on the position of direct band gaps and the dispersion of the effective mass are revealed by the electronic-structure calculation. Our photoelectron transport results show a red shift of the imaginary part of the dielectric function with the increase of the number of acetylene bonds. Furthermore, the loss function and extinction coefficient move to the low-energy region with the increase of n. These findings show that the optical parameters could be tuned and manipulated by the number of acetylene bonds to fulfill different applications.
Acknowledgments
This work was financially supported by the Sumin Zeng Project in Southwest University (ZSM2021008), the Fundamental Research Funds for the Central Universities (XDJK2017B043), and the Singapore MOE Tier 1 grant (R- 265-000-691-114).
Supporting Information Available
The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acsomega.1c00840.
Total and partial density of states, chemical bond analysis, charge density difference, and photoabsorption of graphyne-n (PDF)
Author Contributions
∥ Y.L. and J.W. contributed equally to this work.
The authors declare no competing financial interest.
Notes
The data that support the findings of this study can be obtained from the corresponding author upon reasonable request.
Supplementary Material
References
- Krätschmer W.; Lamb Lowell D.; Fostiropoulos K.; Huffman Donald R. Solid C60: a new form of carbon. Nature 1990, 347, 354–358. 10.1038/347354a0. [DOI] [Google Scholar]
- Iijima S. Helical microtubules of graphitic carbon. Nature 1991, 354, 56–58. 10.1038/354056a0. [DOI] [Google Scholar]
- Novoselov K. S.; Geim A. K.; Morozov S. V.; Jiang D.; Zhang Y.; Dubonos S. V.; Grigorieva I. V.; Firsov A. A. Electric Field Effect in Atomically Thin Carbon Films. Science 2004, 36, 666–669. 10.1126/science.1102896. [DOI] [PubMed] [Google Scholar]
- Baughman R. H.; Eckhardt H.; Kertesz M. Structure-property predictions for new planar forms of carbon: Layered phases containing Sp2 and sp atoms. J. Chem. Phys. 1987, 87, 6687–6699. 10.1063/1.453405. [DOI] [Google Scholar]
- Li Y.; Xu L.; Liu H.; Li Y. Graphdiyne and graphyne: from theoretical predictions to practical construction. Chem. Soc. Rev. 2014, 43, 2572. 10.1039/c3cs60388a. [DOI] [PubMed] [Google Scholar]
- Peng Q.; Dearden A. K.; Crean J.; Han L.; Liu S.; Wen X.; De S. New materials graphyne, graphdiyne, graphone, and graphane: review of properties, synthesis, and application in nanotechnology. Nanotechnol., Sci. Appl. 2014, 7, 1–29. 10.2147/NSA.S40324. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Li G. X.; Li Y. L.; Liu H. B.; Guo Y. B.; Li Y. J.; Zhu D. B. Architecture of graphdiyne nanoscale films. Chem. Commun. 2010, 46, 3256–3258. 10.1039/b922733d. [DOI] [PubMed] [Google Scholar]
- Shang H.; Zou Z.; Li L.; Wang F.; Liu H. B.; Li Y. J.; Li Y. L. Ultrathin Graphdiyne Nanosheets Grown In Situ on Copper Nanowires and Their Performance as Lithium-Ion Battery Anodes. Angew. Chem., Int. Ed. 2018, 57, 774–778. 10.1002/anie.201711366. [DOI] [PubMed] [Google Scholar]
- Zhou W. X.; Shen H.; Wu C.; Tu Z.; He F.; Gu Y.; Xue Y.; Zhao Y.; Yi Y.; Li Y.; Li Y. Direct Synthesis of Crystalline Graphdiyne Analogue Based on Supramolecular Interactions. J. Am. Chem. Soc. 2019, 141, 48–52. 10.1021/jacs.8b09945. [DOI] [PubMed] [Google Scholar]
- Han Y. Y.; Lu X. L.; Tang S. F.; Yin X. P.; Wei Z. W.; Lu T. B. Metal-Free 2D/2D Heterojunction of Graphitic Carbon Nitride/Graphdiyne for Improving the Hole Mobility of Graphitic Carbon Nitride. Adv. Energy Mater. 2018, 8, 1702992–1702999. 10.1002/aenm.201702992. [DOI] [Google Scholar]
- He J.; Bao K.; Cui W.; Yu J.; Huang C.; Shen X.; Cui Z.; Wang N. Construction of Large-Area Uniform Graphdiyne Film for High-Performance Lithium-Ion Batteries. Chem. - Eur. J. 2018, 24, 1187–1192. 10.1002/chem.201704581. [DOI] [PubMed] [Google Scholar]
- Liu R.; Liu H.; Li Y.; Yi Y.; Shang X.; Zhang S.; Yu X.; Zhang S.; Cao H.; Zhang G. Nitrogen-doped graphdiyne as a metal-free catalyst for high-performance oxygen reduction reactions. Nanoscale 2014, 6, 11336–11343. 10.1039/C4NR03185G. [DOI] [PubMed] [Google Scholar]
- Liu R.; Zhou J.; Gao X.; Li J.; Xie Z.; Li Z.; Zhang S.; Tong L.; Zhang J.; Liu Z. Graphdiyne Filter for Decontaminating Lead-Ion-Polluted Water. Adv. Electron. Mater. 2017, 3, 1700122 10.1002/aelm.201700122. [DOI] [Google Scholar]
- Parvin N.; Jin Q.; Wei Y.; Yu R.; Zheng B.; Huang L.; Zhang Y.; Wang L.; Zhang H.; Gao M.; et al. Few-Layer Graphdiyne Nanosheets Applied for Multiplexed Real-Time DNA Detection. Adv. Mater. 2017, 29, 1606755 10.1002/adma.201606755. [DOI] [PubMed] [Google Scholar]
- Wang S.; Yi L.; Halpert J. E.; Lai X.; Liu Y.; Cao H.; Yu R.; Wang D.; Li Y. A Novel and Highly Efficient Photocatalyst Based on P25–Graphdiyne Nanocomposite. Small 2012, 8, 265–271. 10.1002/smll.201101686. [DOI] [PubMed] [Google Scholar]
- Xue Y.; Zou Z.; Li Y.; Liu H.; Li Y. Graphdiyne-Supported NiCo2S4 Nanowires: A Highly Active and Stable 3D Bifunctional Electrode Material. Small 2017, 13, 1700936 10.1002/smll.201700936. [DOI] [PubMed] [Google Scholar]
- Zhang H.; Xia Y.; Bu H.; Wang X.; Zhang M.; Lou Y.; Zhao M. Graphdiyne: A promising anode material for lithium ion batteries with high capacity and rate capability. J. Appl. Phys. 2013, 113, 044309 10.1063/1.4789635. [DOI] [Google Scholar]
- Zhang S.; Liu H.; Huang C.; Cui G.; Li Y. Bulk graphdiyne powder applied for highly efficient lithium storage. Chem. Commun. 2015, 51, 1834–1837. 10.1039/C4CC08706B. [DOI] [PubMed] [Google Scholar]
- Zou Z.; Shang H.; Chen Y.; Li J.; Liu H.; Li Y.; Li Y. A facile approach for graphdiyne preparation under atmosphere for an advanced battery anode. Chem. Commun. 2017, 53, 8074–8077. 10.1039/C7CC03200E. [DOI] [PubMed] [Google Scholar]
- Padilha J. E.; Fazzio A.; Silva A. J. R. Directional Control of the Electronic and Transport Properties of Graphynes. J. Phys. Chem. C 2014, 118, 18793–18798. 10.1021/jp5062804. [DOI] [Google Scholar]
- Chen J.; Xi J.; Wang D.; Shuai Z. Carrier Mobility in Graphyne Should Be Even Larger than That in Graphene: A Theoretical Prediction. J. Phys. Chem. Lett. 2013, 4, 1443–1448. 10.1021/jz4005587. [DOI] [PubMed] [Google Scholar]
- Kuang C.; Tang G.; Jiu T.; Yang H.; Liu H.; Li B.; Luo W.; Luo W.; Li X.; Zhang W.; Lu F.; et al. Highly Efficient Electron Transport Obtained by Doping PCBM with Graphdiyne in Planar-Heterojunction Perovskite Solar Cells. Nano Lett. 2015, 15, 2756–2762. 10.1021/acs.nanolett.5b00787. [DOI] [PubMed] [Google Scholar]
- Luo G.; Qian X.; Liu H.; Qin R.; Zhou J.; Li L.; Gao Z.; Wang E.; Mei W. N.; Lu J.; et al. Quasiparticle energies and excitonic effects of the two-dimensional carbon allotrope graphdiyne: Theory and experiment. Phys. Rev. B: Condens. Matter Mater. Phys. 2011, 84, 075439 10.1103/PhysRevB.84.075439. [DOI] [Google Scholar]
- Perdew J. P.; Burke K.; Ernzerhof M. Generalized Gradient Approximation Made Simple. Phys. Rev. Lett. 1997, 78, 1396. 10.1103/PhysRevLett.78.1396. [DOI] [PubMed] [Google Scholar]
- Segall M. D.; Lindan P. J. D.; Probert M.; Pickard C. J.; Hasnip P. J.; Clark S. J.; Payne M. C. First-principles simulation: ideas, illustrations and the CASTEP code. J. Phys.: Condens. Matter 2002, 14, 2717. 10.1088/0953-8984/14/11/301. [DOI] [Google Scholar]
- Vanderbilt D. Soft self-consistent pseudopotentials in a generalized eigenvalue formalism. Phys. Rev. B: Condens. Matter Mater. Phys. 1990, 41, 7892. 10.1103/PhysRevB.41.7892. [DOI] [PubMed] [Google Scholar]
- Grimme S.; Antony J.; Ehrlich S.; Krieg H. A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu. J. Chem. Phys. 2010, 132, 154104 10.1063/1.3382344. [DOI] [PubMed] [Google Scholar]
- Chadi D. J. Special points for Brillouin-zone integrations. Phys. Rev. B: Condens. Matter Mater. Phys. 1977, 16, 1746. 10.1103/PhysRevB.16.1746. [DOI] [Google Scholar]
- Puigdollers A. R.; Alonso G.; Gamallo P. First-principles study of structural, elastic and electronic properties of α-, β- and γ-graphyne. Carbon 2016, 96, 879–887. 10.1016/j.carbon.2015.10.043. [DOI] [Google Scholar]
- Dickman S.; Senozan N. M.; Hunt R. L. Thermodynamic Properties and the Cohesive Energy of Calcium Ammoniate. J. Chem. Phys. 1970, 52, 2657–2663. 10.1063/1.1673354. [DOI] [Google Scholar]
- Ducéré J.-M.; Lepetit C.; Chauvin R. Carbo-graphite: Structural, Mechanical, and Electronic Properties. J. Phys. Chem. C 2013, 117, 21671–21681. 10.1021/jp4067795. [DOI] [Google Scholar]
- Naritta N.; Nagai S.; Suzuki S.; Nakao K. Optimized geometries and electronic structures of graphyne and its family. Phys. Rev. B 1998, 58, 11009. 10.1103/PhysRevB.58.11009. [DOI] [Google Scholar]
- Yue Q.; Chang S.; Kang J.; Qin S.; Li J. Mechanical and Electronic Properties of Graphyne and Its Family under Elastic Strain: Theoretical Predictions. J. Phys. Chem. C 2013, 117, 14804–14811. 10.1021/jp4021189. [DOI] [Google Scholar]
- Cranford S. W.; Brommer D. B.; Buehler M. Extended graphynes: simple scaling laws for stiffness, strength and fracture. Nanoscale 2012, 4, 7797–7809. 10.1039/c2nr31644g. [DOI] [PubMed] [Google Scholar]
- Harald I.; Hans L.; Laszlo M.; David M. Solid-State Physics: An Introduction to Theory and Experiment. Am. J. Phys. 1992, 60, 1053–1054. 10.1119/1.16993. [DOI] [Google Scholar]
- Srinivasu K.; Ghosh S. K. Graphyne and Graphdiyne: Promising Materials for Nanoelectronics and Energy Storage Applications. J. Phys. Chem. C 2012, 116, 5951–5956. 10.1021/jp212181h. [DOI] [Google Scholar]
- Zhou J.; Lv K.; Wang Q.; Chen X. S.; Sun Q.; Jena P. Electronic structures and bonding of graphyne sheet and its BN analog. J. Chem. Phys. 2011, 134, 174701 10.1063/1.3583476. [DOI] [PubMed] [Google Scholar]
- Long M.; Tang L.; Wang D.; Li Y.; Shuai Z. Electronic Structure and Carrier Mobility in Graphdiyne Sheet and Nanoribbons: Theoretical Predictions. ACS Nano 2011, 5, 2593–2600. 10.1021/nn102472s. [DOI] [PubMed] [Google Scholar]
- Zheng Q.; Luo G.; Liu Q.; Quhe R.; Zheng J.; Tang K.; Gao Z.; Nagase S.; Lu J. Structural and electronic properties of bilayer and trilayer graphdiyne. Nanoscale 2012, 4, 3990–3996. 10.1039/c2nr12026g. [DOI] [PubMed] [Google Scholar]
- Shen L.; Zeng M.; Yang S. W.; Zhang C.; Wang X.; Feng Y. Electron Transport Properties of Atomic Carbon Nanowires between Graphene Electrodes. J. Am. Chem. Soc. 2010, 132, 11481–11486. 10.1021/ja909531c. [DOI] [PubMed] [Google Scholar]
- Zhang L.; Li H.; Feng Y. P.; Shen L. Diverse Transport Behaviors in Cyclo[18]carbon-Based Molecular Devices. J. Phys. Chem. Lett. 2020, 11, 2611–2617. 10.1021/acs.jpclett.0c00357. [DOI] [PubMed] [Google Scholar]
- Tran F.; Blaha P. Importance of the Kinetic Energy Density for Band Gap Calculations in Solids with Density Functional Theory. J. Phys. Chem. A 2017, 121, 3318–3325. 10.1021/acs.jpca.7b02882. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Deák P.; Aradi B.; Frauenheim T.; Janzén E.; Gali A. Accurate defect levels obtained from the HSE06 range-separated hybrid functional. Phys. Rev. B 2010, 81, 153203 10.1103/PhysRevB.81.153203. [DOI] [Google Scholar]
- Kang J.; Li J.; Wu F.; Li S. S.; Xia J. B. Elastic, Electronic, and Optical Properties of Two-Dimensional Graphyne Sheet. J. Phys. Chem. C 2011, 115, 20466–20470. 10.1021/jp206751m. [DOI] [Google Scholar]
- Okoye C. M. I. Theoretical study of the electronic structure, chemical bonding and optical properties of KNbO3 in the paraelectric cubic phase. J. Phys.: Condens. Matter 2003, 15, 5945. 10.1088/0953-8984/15/35/304. [DOI] [Google Scholar]
- Kronig R. D. L. On the Theory of Dispersion of X-Rays. J. Opt. Soc. Am. 1926, 12, 547–557. 10.1364/JOSA.12.000547. [DOI] [Google Scholar]
- Xie Z.; Hui L.; Wang J.; Zhu G.; Chen Z.; Li C. Electronic and optical properties of monolayer black phosphorus induced by bi-axial strain. Comput. Mater. Sci. 2018, 144, 304–314. 10.1016/j.commatsci.2017.12.026. [DOI] [Google Scholar]
- Zheng S.; Wu E.; Feng Z.; Zhang R.; Xie Yuan.; Yu Y.; Zhang R.; Li Q.; Liu J.; Pang W.; et al. Acoustically enhanced photodetection by a black phosphorus–MoS2 van der Waals heterojunction p–n diode. Nanoscale 2018, 10, 10148–10153. 10.1039/C8NR02022A. [DOI] [PubMed] [Google Scholar]
- Almeida J. S.; Ahuja R. Tuning the structural, electronic, and optical properties of BexZn1–xTe alloys. Appl. Phys. Lett. 2006, 89, 061913 10.1063/1.2219341. [DOI] [Google Scholar]
- Ma T. H.; Yang C. H.; Xie Y.; Sun L.; Lv W. Q.; Wang R.; Zhu C. Q.; Wang M. Electronic and optical properties of orthorhombic LiInS2 and LiInSe2: A density functional theory investigation. Comput. Mater. Sci. 2009, 47, 99–105. 10.1016/j.commatsci.2009.06.021. [DOI] [Google Scholar]
- Srikant V.; Clarke D. R. Optical absorption edge of ZnO thin films: The effect of substrate. J. Appl. Phys. 1997, 81, 6357. 10.1063/1.364393. [DOI] [Google Scholar]
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