Morphological and Structural Investigation of Sexithiophene Growth on KCl (100)

Schwabegger, Günther; Djuric, Tatjana; Sitter, H.; Resel, Roland; Simbrunner, Clemens

doi:10.1021/cg3010823

Cited by 24 publications

(41 citation statements)

References 39 publications

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“…We computed the PC KCl lattice constant through minimization of the total energy by employing the parameters shown in Table 1 . The obtained result was 4.507 Å for the FCC PC system, which is in agreement with the experimental lattice constant of 6.29 Å [ 3 , 33 , 34 , 35 ]—larger by 1.22% and is slightly shorter by 0.3%—compared with other theoretical calculations that obtained 4.522 Å [ 71 ]. It is more similar to other calculations that used an all-electron scheme [ 28 ] (see Table 2 ).…”

Section: Resultssupporting

confidence: 90%

“…In this structure, an octahedron of six counterions surrounds each ion; hence, the coordination number is six for both the anion, Cl − , and cation, K + . The experimental lattice constant is 6.29 Å [ 3 , 33 , 34 , 35 ]. Figure 1 a shows the FCC primitive cell (PC) of pristine KCl, with two atoms at the base; the cation K + is located at the [0,0,0] position, and the anion Cl − is located at the [1/2,1/2,1/2] position, for which the Brillouin zone (BZ) is a truncated octahedron [ 36 , 37 ], and its primitive vectors are [0, 1/2,1/2], [1/2,0,1/2], and [1/2,1/2,0].…”

Section: Theoretical Methods and Computational Detailsmentioning

confidence: 99%

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Cu-Doped KCl Unfolded Band Structure and Optical Properties Studied by DFT Calculations

et al. 2020

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The unfolded band structure and optical properties of Cu-doped KCl crystals were computed by first principles within the framework of density functional theory, implemented in the ABINIT software program, utilizing pseudopotential approximation and a plane-wave basis set. From a theoretical point of view, Cu substitution into pristine KCl crystals requires calculation by the supercell (SC) method. This procedure shrinks the Brillouin zone, resulting in a folded band structure that is difficult to interpret. To solve this problem and gain insight into the effect of copper ions (Cu+) on electronic properties, the band structure of SC KCl:Cu was unfolded to make a direct comparison with the band structure of the primitive cell (PC) of pristine KCl. To understand the effect of Cu substitution on optical absorption, we calculated the imaginary part of the dielectric function of KCl:Cu through a sum-over-states formalism and broke it down into different band contributions by partially making an iterated cumulative sum (ICS) of selected valence and conduction bands. Consequently, we identified those interband transitions that give rise to the absorption peaks due to the Cu+ ion. These transitions involve valence and conduction bands formed by the Cu-3d and Cu-4s electronic states.

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Section: Resultssupporting

confidence: 90%

Section: Theoretical Methods and Computational Detailsmentioning

confidence: 99%

Cu-Doped KCl Unfolded Band Structure and Optical Properties Studied by DFT Calculations

et al. 2020

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“…Moreover, multiple crystal orientations of the same crystal phase can appear, and different polymorphs within a single sample can be present. 38 , 39 In our previous work, we have shown the theoretical concept of the assignment of diffraction peaks to individually oriented crystallites. 40 In this paper, we will apply this methodology to a number of examples with known and unknown bulk polymorphs.…”

Section: Introductionmentioning

confidence: 99%

Searching for New Polymorphs by Epitaxial Growth

et al. 2020

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The formation of unknown polymorphs due to the crystallization at a substrate surface is frequently observed. This phenomenon is much less studied for epitaxially grown molecular crystals since the unambiguous proof of a new polymorph is a challenging task. The existence of multiple epitaxial alignments of the crystallites together with the simultaneous presence of different polymorphs does not allow simple phase identification. We present grazing incidence X-ray diffraction studies on conjugated molecules like perylenetetracarboxylic dianhydride (PTCDA), pentacene, dibenzopentacene (trans-DBPen), and dicyanovinylquater-thiophene (DCV4T-Et2) grown by physical vapor deposition on single crystalline surfaces like Ag(111), Cu(111), and graphene. A new method for indexing the observed Bragg peaks allows the determination of the crystallographic unit cells so that the type of crystallographic phase can be clearly identified. This approach even works when several polymorphs are simultaneously present within a single sample as shown for DCV4T-Et2 on Ag(111). Additionally, epitaxial relationships between the epitaxially grown crystallites and the single crystalline surfaces are determined. In a subsequent step, the experimental data are used for the crystal structure solution of an unknown polymorph, as shown for the example trans-DBPen grown on Cu(111).

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“…In this structure, an octahedron of six counterions surrounds each ion; hence, the coordination number is six for both the anion, Cl − , and cation, K − . The experimental lattice constant is 6.29 Å [3,[33][34][35]. Figure 1(a) shows the FCC primitive cell (PC) of pristine KCl, with two atoms at the base; the cation K − is located at the [0,0,0] position, and the anion Cl − is located at the [1/2,1/2,1/2] position, for which the Brillouin zone (BZ) is a truncated octahedron [36,37] The six Cl − anions surrounding the monovalent Cu + cation are asymmetric.…”

Section: Theoretical Methods and Computational Detailsmentioning

confidence: 99%

Cu-Doped KCl Unfolded Band Structure and Optical Properties Studied by DFT Calculations

Castillo-Quevedo¹,

Cabellos²,

Aceves³

et al. 2020

Preprint

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The unfolded band structure and optical properties of Cu-doped KCl crystals were computed by first principles within the framework of density functional theory, implemented in the ABINIT electronic structure package utilizing pseudopotential approximation and a plane-wave basis set. From a theoretical point of view, Cu substitution into pristine KCl crystals requires calculation by the supercell (SC) method. This procedure shrinks the Brillouin zone, resulting in a folded band structure that is difficult to interpret. To solve this problem and gain insight into the effect of copper ions (Cu+) on electronic properties, the band structure of SC KCl:Cu was unfolded to make a direct comparison with the band structure of the primitive cell (PC) of pristine KCl. To understand the effect of Cu substitution on optical absorption, we calculated the imaginary part of the dielectric function of KCl:Cu through a sum-over-states formalism and broke it down into different band contributions by partially making an iterated cumulative sum (ICS) of selected valence and conduction bands. Consequently, we identified those interband transitions that give rise to the absorption peaks due to the Cu+ ion. These transitions involve valence and conduction bands formed by the Cu-3d and Cu-4s electronic states

show abstract

Morphological and Structural Investigation of Sexithiophene Growth on KCl (100)

Cited by 24 publications

References 39 publications

Cu-Doped KCl Unfolded Band Structure and Optical Properties Studied by DFT Calculations

Cu-Doped KCl Unfolded Band Structure and Optical Properties Studied by DFT Calculations

Searching for New Polymorphs by Epitaxial Growth

Cu-Doped KCl Unfolded Band Structure and Optical Properties Studied by DFT Calculations

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