Optical absorption and energy loss spectroscopy of single-walled carbon nanotubes

Preciado-Rivas, María Rosa; Torres-Sánchez, Victor Alexander; Mowbray, D. J.

doi:10.1103/physrevb.100.235429

Cited by 8 publications

(13 citation statements)

References 59 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To do so, we employ the derivative discontinuity correction to the exchange (x) part of the Gritsenko, van Leeuwen, van Lenthe, and Baerends solid and correlation (GLLB-SC) [31] functional to perform an ab initio upshift of the unoccupied KS eigenenergies either a priori or a posteriori. This approach already successfully described the optical absorbance of both 0D chlorophyll monomers [32] and 1D SWCNTs [33].…”

Section: Introductionmentioning

confidence: 94%

LCAO-TDDFT-k- ω : spectroscopy in the optical limit

Lyon

Preciado-Rivas²,

Zamora‐Ledezma³

et al. 2020

J. Phys.: Condens. Matter

Self Cite

View full text Add to dashboard Cite

Understanding, optimizing, and controlling the optical absorption process, exciton gemination, and electron-hole separation and conduction in low dimensional systems is a fundamental problem in materials science. However, robust and efficient methods capable of modelling the optical absorbance of low dimensional macromolecular systems and providing physical insight into the processes involved have remained elusive. We employ a highly efficient linear combination of atomic orbitals (LCAOs) representation of the Kohn-Sham (KS) orbitals within time dependent density functional theory (TDDFT) in the reciprocal space (k) and frequency (ω) domains, as implemented within our LCAO-TDDFT-k-ω code, applying either a priori or a posteriori the derivative discontinuity correction of the exchange functional Δ x to the KS eigenenergies as a scissors operator. In so doing we are able to provide a semi-quantitative description of the photoabsorption cross section, conductivity, and dielectric function for prototypical 0D, 1D, 2D, and 3D systems within the optical limit ( q → 0 + ) as compared to both available measurements and from solving the Bethe-Salpeter equation with quasiparticle G 0 W 0 eigenvalues (G 0 W 0 -BSE). Specifically, we consider 0D fullerene (C 60 ), 1D metallic (10, 0) and semiconducting (10, 10) single-walled carbon nanotubes, 2D graphene (Gr) and phosphorene (Pn), and 3D rutile (R-TiO 2 ) and anatase (A-TiO 2 ). For each system, we also employ the spatially and energetically resolved electron-hole spectral density to provide direct physical insight into the nature of their optical excitations. These results demonstrate the reliability, applicability, efficiency, and robustness of our LCAO-TDDFT-k-ω code, and open the pathway to the computational design of macromolecular systems for optoelectronic, photovoltaic, and photocatalytic applications in silico.

show abstract

Section: Introductionmentioning

confidence: 94%

LCAO-TDDFT-k- ω : spectroscopy in the optical limit

Lyon

Preciado-Rivas²,

Zamora‐Ledezma³

et al. 2020

J. Phys.: Condens. Matter

Self Cite

View full text Add to dashboard Cite

show abstract

“…Nowadays, the optical properties of SWCNT films are characterized by a variety of spectroscopic techniques, including absorption 16,17 and electron energy-loss spectroscopies. 18,19 Meanwhile, morphology and geometrical parameters are determined by transmission electron (TEM), 20,21 scanning electron (SEM), 22,23 and atomic force (AFM) 24,25 microscopies. All these methods are time-and resource-consuming and require additional sample preparation steps, which might affect the properties of SWCNT films and, therefore, do not represent the actual properties of films used in applications.…”

mentioning

confidence: 99%

Express determination of thickness and dielectric function of single-walled carbon nanotube films

Ermolaev

Tsapenko

Volkov

et al. 2020

Applied Physics Letters

View full text Add to dashboard Cite

Single-walled carbon nanotube (SWCNT) films are promising building blocks for diversified applications in electronics, photovoltaics, and photonics. However, their electrical and optical engineering is still a challenging task owing to multiple obstacles, including the absence of fast and easy-to-use methods for the determination of SWCNT film properties. Here, we present a rapid, contactless, and universal technique for accurate estimation of both SWCNT film thicknesses and their dielectric functions. The approach combines broadband optical absorbance and highly sensitive spectroscopic ellipsometry measurements. The observed linear dependence of the film thickness on its absorbance at 550 nm provides a time-effective and contactless method of thickness assignment, which is of significant importance to the practical implementation of SWCNT films in optoelectronic devices. Additionally, our approach revealed that a simple procedure of film densification allows to controllably alter the dielectric response by at least 40% and, thus, to add extra fine-tuning capabilities during material property engineering. Therefore, this express technique as a whole offers an advanced metrological tool for current and next-generation SWCNT-based devices.

show abstract

“…This dramatic decrease in the RBM frequency is consistent with the filling of the e-doped SWCNT's CBM, i.e., the first van Hove singularity. Moreover, the initial slope exhibits a quasi-linear dependence on the diameter, with d ≈ 0.784, 0.831, 0.916, and 0.936 nm for the (8,3), (7,5), (11,1), and (10,3) SWCNTs, respectively 42 (Figure 5b,c). These findings provide empirical justification of our model of the RBM downshift provided in eqs 2 and 3.…”

Section: ■ Results and Discussionmentioning

confidence: 96%

“…In addition, for similar diameters it is ruled by the band gap energy E 11 . Figure b illustrates the theoretical versus experimental E 11 transition energies from refs and for the semiconducting SWCNT species found in our enriched HiPco samples.…”

Section: Discussionmentioning

confidence: 95%

“…(a) Schematic of electronic density of states of semiconducting (left) and metallic (right) SWCNTs, with optical transitions between the first (S 11 /M 11 ) and second (S 22 ) van Hove singularities marked in red. (b) Theoretical versus experimental E 11 transition energies for the semiconducting HiPco SWCNT samples from refs and , respectively. (c) SWCNT indices ( n , m ) with semiconducting (red) and metallic (blue) SWCNTs in our samples marked.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Understanding the Electron-Doping Mechanism in Potassium-Intercalated Single-Walled Carbon Nanotubes

et al. 2020

Self Cite

View full text Add to dashboard Cite

Single-walled carbon nanotubes (SWCNTs) can be doped with potassium, similar to graphite, leading to intercalation compounds. These binary systems exhibit a clear metallic character. However, the entire picture of how electron doping (edoping) modifies the SWCNTs' vibrational spectra as a function of their diameter, chirality, and metallicity is still elusive. Herein, we present a detailed study of the intercalation and solid state reduction of metallic and semiconducting enriched HiPco ® SWCNTs. We performed a combined experimental and theoretical study of the evolution of their Raman response with potassium exposure, focusing specifically on their radial breathing mode (RBM). We found the charge donated from the potassium atoms occupies anti-bonding π orbitals of the SWCNTs, weakening their C-C bonds, and reducing the RBM frequency. This RBM downshift with increasing doping level is quasi-linear with a step-like behavior when the Fermi level crosses a van Hove singularity for semiconducting species. Moreover, this weakening of the C-C bonds is greater with decreasing curvature, or increasing diameter. Overall, this suggests the RBM downshift with e-doping is proportional to both the SWCNT's integrated density of states (DOS) ϱ(ε) and diameter d. We have provided a precise and complete description of the complex electron doping mechanism in SWCNTs up to a charge density of -18 me/C, far beyond that achievable by standard gate voltage studies, based on their excitation energy, diameter, band gap energy, chiral angle, and metallicity. This work is highly relevant to tuning the electronic properties of SWCNTs for applications in nanoelectronics, plasmonics, and thermoelectricity.

show abstract

Optical absorption and energy loss spectroscopy of single-walled carbon nanotubes

Cited by 8 publications

References 59 publications

LCAO-TDDFT-k- ω : spectroscopy in the optical limit

LCAO-TDDFT-k- ω : spectroscopy in the optical limit

Express determination of thickness and dielectric function of single-walled carbon nanotube films

Understanding the Electron-Doping Mechanism in Potassium-Intercalated Single-Walled Carbon Nanotubes

Contact Info

Product

Resources

About