1
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Eguchi K, Murata H. The ionization energy of α-sexithiophene and p-sexiphenyl in 2D and 3D thin films grown on silicon oxide surfaces. Phys Chem Chem Phys 2024; 26:8687-8694. [PMID: 37947076 DOI: 10.1039/d3cp04475k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
The ionization energy (IE) of molecular thin films is sensitive to the molecular environments surrounding ionized molecules. In this study, we investigate the evolution of the IE on dimension-controlled 2D and 3D thin films of rod-like molecules, namely α-sexithiophene (α-6T) and p-sexiphenyl (p-6P), grown on SiO2 surfaces via photoelectron yield spectroscopy. In 2D thin films, the IE of α-6T and p-6P showed nearly constant values of 4.93 eV and 5.50 eV, respectively. In 3D thin films, however, with increasing coverage, the IE of the α-6T thin films gradually decreased to 4.84 eV at 15 ML (ML: monolayer) and the IE of the p-6P thin films gradually increased to 5.65 eV at 7 ML. These experimental findings underline the less significant impact of the domain size on the IE in 2D thin films and the significant impact of the neighboring layers on the IE in 3D thin films.
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Affiliation(s)
- Keitaro Eguchi
- School of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa 923-1292, Japan.
| | - Hideyuki Murata
- School of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa 923-1292, Japan.
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2
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Günder D, Diez-Cabanes V, Huttner A, Breuer T, Lemaur V, Cornil J, Witte G. F-Center-Mediated Growth of Patterned Organic Semiconductor Films on Alkali Halides. ACS APPLIED MATERIALS & INTERFACES 2022; 14:46086-46094. [PMID: 36191090 DOI: 10.1021/acsami.2c13934] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Organic semiconductors combine flexible tailoring of their optoelectronic properties by synthetic means with strong light-matter coupling, which is advantageous for organic electronic device applications. Although spatially selective deposition has been demonstrated, lateral patterning of organic films with simultaneous control of molecular and crystalline orientation is lacking as traditional lithography is not applicable. Here, a new patterning approach based on surface-localized F-centers (halide vacancies) generated by electron irradiation of alkali halides is presented, which allows structural control of molecular adlayers. Combining optical and atomic force microscopy, X-ray diffraction, and density functional theory (DFT) calculations, it is shown that dinaphthothienothiophene (DNTT) molecules adopt an upright orientation on pristine KCl surfaces, while the F-centers stabilize a recumbent orientation, and that these orientations are maintained in thicker films. This specific nucleation results also in different crystallographic morphologies, namely, densely packed islands and jagged fibers, each epitaxially aligned on the KCl surface. Spatially selective surface irradiation can also be used to create patterns of F-centers and thus laterally patterned DNTT films, which can be further transferred to any (including elastomer) substrate due to the water solubility of the alkali halide growth templates.
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Affiliation(s)
- Darius Günder
- Fachbereich Physik, Philipps-Universität Marburg, 35032 Marburg, Germany
| | - Valentin Diez-Cabanes
- Laboratory for Chemistry of Novel Materials, University of Mons (UMONS), BE-7000 Mons, Belgium
- Laboratoire de Physique et Chimie Théoriques (LPCT), Université de Lorraine & CNRS, F-54000 Nancy, France
| | - Andrea Huttner
- Fachbereich Physik, Philipps-Universität Marburg, 35032 Marburg, Germany
| | - Tobias Breuer
- Fachbereich Physik, Philipps-Universität Marburg, 35032 Marburg, Germany
| | - Vincent Lemaur
- Laboratory for Chemistry of Novel Materials, University of Mons (UMONS), BE-7000 Mons, Belgium
| | - Jérôme Cornil
- Laboratory for Chemistry of Novel Materials, University of Mons (UMONS), BE-7000 Mons, Belgium
| | - Gregor Witte
- Fachbereich Physik, Philipps-Universität Marburg, 35032 Marburg, Germany
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3
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Simbrunner J, Domke J, Forker R, Resel R, Fritz T. Correlation between two- and three-dimensional crystallographic lattices for epitaxial analysis. I. Theory. Acta Crystallogr A Found Adv 2022; 78:262-271. [PMID: 35502717 PMCID: PMC9062828 DOI: 10.1107/s2053273322002182] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 02/23/2022] [Indexed: 11/24/2022] Open
Abstract
A general formalism to determine the surface unit cell of a three-dimensional crystallographic lattice is presented. The epitaxial growth of molecular crystals at single-crystalline surfaces is often strongly related to the first monolayer at the substrate surface. The present work presents a theoretical approach to compare three-dimensional lattices of epitaxially grown crystals with two-dimensional lattices of the molecules formed within the first monolayer. Real-space and reciprocal-space representations are considered. Depending on the crystallographic orientation relative to the substrate surface, proper linear combinations of the lattice vectors of the three-dimensional unit cell result in a rhomboid in the xy plane, representing a two-dimensional projection. Mathematical expressions are derived which provide a relationship between the six lattice parameters of the three-dimensional case and the three parameters obtained for the two-dimensional surface unit cell. It is found that rotational symmetries of the monolayers are reflected by the epitaxial order. Positive and negative orientations of the crystallographic contact planes are correlated with the mirror symmetry of the surface unit cells, and the corresponding mathematical expressions are derived. The method is exemplarily applied to data obtained in previous grazing-incidence X-ray diffraction (GIXD) measurements with sample rotation on thin films of the conjugated molecules 3,4;9,10-perylenetetracarboxylic dianhydride (PTCDA), 6,13-pentacenequinone (P2O), 1,2;8,9-dibenzopentacene (trans-DBPen) and dicyanovinyl-quaterthiophene (DCV4T-Et2) grown by physical vapor deposition on Ag(111) and Cu(111) single crystals. This work introduces the possibility to study three-dimensional crystal growth nucleated by an ordered monolayer by combining two different experimental techniques, GIXD and low-energy electron diffraction, which has been implemented in the second part of this work.
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4
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Simbrunner J, Schrode B, Hofer S, Domke J, Fritz T, Forker R, Resel R. Searching for New Polymorphs by Epitaxial Growth. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2021; 125:618-626. [PMID: 33488907 PMCID: PMC7818500 DOI: 10.1021/acs.jpcc.0c10021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 11/24/2020] [Indexed: 06/12/2023]
Abstract
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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Affiliation(s)
- Josef Simbrunner
- Department
of Neuroradiology, Vascular and Interventional Radiology, Medical University Graz, Auenbruggerplatz 9, Graz 8036, Austria
| | - Benedikt Schrode
- Institute
of Solid State Physics, Graz University
of Technology, Petersgasse 16, Graz 8010, Austria
| | - Sebastian Hofer
- Institute
of Solid State Physics, Graz University
of Technology, Petersgasse 16, Graz 8010, Austria
| | - Jari Domke
- Institute
of Solid State Physics, Friedrich Schiller
University Jena, Helmholtzweg 5, Jena 07743, Germany
| | - Torsten Fritz
- Institute
of Solid State Physics, Friedrich Schiller
University Jena, Helmholtzweg 5, Jena 07743, Germany
| | - Roman Forker
- Institute
of Solid State Physics, Friedrich Schiller
University Jena, Helmholtzweg 5, Jena 07743, Germany
| | - Roland Resel
- Institute
of Solid State Physics, Graz University
of Technology, Petersgasse 16, Graz 8010, Austria
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5
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Castillo-Quevedo C, Cabellos JL, Aceves R, Núñez-González R, Posada-Amarillas A. Cu-Doped KCl Unfolded Band Structure and Optical Properties Studied by DFT Calculations. MATERIALS (BASEL, SWITZERLAND) 2020; 13:E4300. [PMID: 32993129 PMCID: PMC7579127 DOI: 10.3390/ma13194300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 09/16/2020] [Accepted: 09/22/2020] [Indexed: 11/25/2022]
Abstract
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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Affiliation(s)
- César Castillo-Quevedo
- Departamento de Fundamentos del Conocimiento, Centro Universitario del Norte, Universidad de Guadalajara, Carretera Federal No. 23, Km. 191, C.P. 46200 Colotlán, Jalisco, Mexico;
| | - Jose Luis Cabellos
- Departamento de Investigación en Física, Universidad de Sonora, Blvd. Luis Encinas y Rosales S/N, 83000 Hermosillo, Sonora, Mexico;
| | - Raul Aceves
- Departamento de Investigación en Física, Universidad de Sonora, Blvd. Luis Encinas y Rosales S/N, 83000 Hermosillo, Sonora, Mexico;
| | - Roberto Núñez-González
- Departamento de Matemáticas, Universidad de Sonora, Blvd. Luis Encinas y Rosales S/N, 83000 Hermosillo, Sonora, Mexico;
| | - Alvaro Posada-Amarillas
- Departamento de Investigación en Física, Universidad de Sonora, Blvd. Luis Encinas y Rosales S/N, 83000 Hermosillo, Sonora, Mexico;
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6
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Farahvash A, Lee CK, Sun Q, Shi L, Willard AP. Machine learning Frenkel Hamiltonian parameters to accelerate simulations of exciton dynamics. J Chem Phys 2020; 153:074111. [DOI: 10.1063/5.0016009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Affiliation(s)
- Ardavan Farahvash
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | | | - Qiming Sun
- Tencent America, Palo Alto, California 94306, USA
| | - Liang Shi
- Department of Chemistry and Chemical Biology, University of California, Merced, California 95343, USA
| | - Adam P. Willard
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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7
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Abd El-Khalek H, Abd- El Salam M, Amin FM. Fabrication and characterization of dual-band organic/inorganic photodetector for optoelectronic applications. CURRENT APPLIED PHYSICS 2019; 19:629-638. [DOI: 10.1016/j.cap.2019.02.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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8
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Duva G, Mann A, Pithan L, Beyer P, Hagenlocher J, Gerlach A, Hinderhofer A, Schreiber F. Template-Free Orientation Selection of Rod-Like Molecular Semiconductors in Polycrystalline Films. J Phys Chem Lett 2019; 10:1031-1036. [PMID: 30767499 DOI: 10.1021/acs.jpclett.9b00304] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Many organic semiconductors (OSCs) feature strong optical anisotropy that can be exploited to increase the efficiency of optoelectronic devices. We demonstrate that for the technologically relevant, rod-like OSCs diindenoperylene (DIP), pentacene (PEN), and α-sexithiophene (6T) deposited on silicon oxide surfaces it is possible to prepare polycrystalline thin films in which the long molecular axis is oriented parallel to the substrate plane in a template-free fashion. In films grown by organic molecular beam deposition at room temperature or higher, the molecules are oriented upright standing (σ-orientation). Instead, the here-presented growth at low temperatures followed by slow annealing up to a temperature near molecular desorption has the effect of "freezing" the molecules with their long axis oriented parallel to the substrate plane (λ-orientation) while conferring them crystalline long-range order. We discuss the huge impact on the optical anisotropy of the films observed as a consequence of the orientation transition. Finally, we propose a mechanism for explaining the achieved λ-orientation, which is stable under environmental conditions.
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Affiliation(s)
- Giuliano Duva
- Institute for Applied Physics , University of Tübingen , Auf der Morgenstelle 10 , 72076 Tübingen , Germany
| | - Alexander Mann
- Institute for Applied Physics , University of Tübingen , Auf der Morgenstelle 10 , 72076 Tübingen , Germany
| | - Linus Pithan
- ESRF The European Synchrotron , 71, Avenue des Martyrs , 38000 Grenoble , France
| | - Paul Beyer
- ESRF The European Synchrotron , 71, Avenue des Martyrs , 38000 Grenoble , France
| | - Jan Hagenlocher
- Institute for Applied Physics , University of Tübingen , Auf der Morgenstelle 10 , 72076 Tübingen , Germany
| | - Alexander Gerlach
- Institute for Applied Physics , University of Tübingen , Auf der Morgenstelle 10 , 72076 Tübingen , Germany
| | - Alexander Hinderhofer
- Institute for Applied Physics , University of Tübingen , Auf der Morgenstelle 10 , 72076 Tübingen , Germany
| | - Frank Schreiber
- Institute for Applied Physics , University of Tübingen , Auf der Morgenstelle 10 , 72076 Tübingen , Germany
- Center for Light-Matter Interactions, Sensors & Analytics (LISA+) , Auf der Morgenstelle, 15 , 72076 Tübingen , Germany
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9
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van Enckevort WJP, Noorduin WL, Graswinckel S, Verwer P, Vlieg E. Epitaxy of Anthraquinone on (100) NaCl: A Quantitative Approach. CRYSTAL GROWTH & DESIGN 2018; 18:5099-5107. [PMID: 30258306 PMCID: PMC6150655 DOI: 10.1021/acs.cgd.8b00546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 07/13/2018] [Indexed: 06/08/2023]
Abstract
A growth cell suitable for microscopic in situ observation of well-controlled crystal growth from the vapor phase is used to study the heteroepitaxial growth of anthraquinone crystals on a (100) NaCl substrate. In this, the morphology, orientation, nucleation, and growth rate of the crystals is studied as a function of driving force, Δμ/kT. At the lowest Δμ/kT, the crystals are block-shaped and show no preferential orientation with respect to the substrate. Increasing the driving force leads to the growth of oriented block- and needle-shaped crystals, which nucleate from macrosteps on the substrate. At the highest Δμ/kT, crystals nucleate on the flat surface areas or at monatomic steps on the substrate, resulting in a dramatic increase in epitaxial needle density. Growth rate measurements show an exponential behavior as a function of Δμ/kT. In all cases, the supply of growth units proceeds via surface diffusion over the NaCl substrate surface toward the anthraquinone crystals. At the lowest Δμ/kT, growth is partly limited by integration of the growth units at the crystal surfaces. At intermediate driving force, kinetic roughening sets in, leading to rounded needle tips. At the highest supersaturation, growth is completely governed by the supply of growth units via surface diffusion, leading to tip splitting as a consequence of morphological instability.
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Affiliation(s)
- Willem. J. P. van Enckevort
- Radboud
University, Institute for Molecules and
Materials, Heyendaalseweg
135, 6525 ED Nijmegen, The Netherlands
| | - Wim L. Noorduin
- Radboud
University, Institute for Molecules and
Materials, Heyendaalseweg
135, 6525 ED Nijmegen, The Netherlands
| | - Sander Graswinckel
- Radboud
University, Institute for Molecules and
Materials, Heyendaalseweg
135, 6525 ED Nijmegen, The Netherlands
| | - Paul Verwer
- Akzo
Nobel Industrial Chemicals, Salt and Crystallization, Deventer, The Netherlands
| | - Elias Vlieg
- Radboud
University, Institute for Molecules and
Materials, Heyendaalseweg
135, 6525 ED Nijmegen, The Netherlands
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10
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Röthel C, Radziown M, Resel R, Grois A, Simbrunner C, Werzer O. Crystal alignment of caffeine deposited onto single crystal surfaces via hot-wall epitaxy. CrystEngComm 2017; 19:2936-2945. [PMID: 28670199 PMCID: PMC5471919 DOI: 10.1039/c7ce00515f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 04/27/2017] [Indexed: 01/09/2023]
Abstract
Crystal growth of caffeine on single crystalline surfaces yields needle or bird-like shaped crystals depending on surface chemistry and symmetry.
Defined crystal growth is highly demanded for technological applications but also fundamental research. Within this work, the crystal growth of the asymmetric molecule caffeine was studied on single crystalline surfaces of muscovite mica, sodium chloride and potassium chloride. While elongated needle-like crystals grow on muscovite mica and sodium chloride, smaller individual “bird-like” structures were observed on potassium chloride. Depending on the surface type and temperature, the disk-shaped caffeine molecules prefer either an edge-on or flat-on orientation with respect to the surface, but in each case, a defined crystallographic relation between the surface and caffeine crystallites was determined by using the X-ray pole figure technique. On muscovite mica and sodium chloride, needle-like crystallites with edge-on oriented molecules aligned mainly with the unit cell c-axis (which coincides with the long needle axis) along the [1–10]mica, [100]mica, [110]mica and [110]NaCl, [1–10]NaCl directions, respectively. Crystals consisting of flat-on oriented molecules on KCl showed also defined alignments with respect to the substrate, but due to the altered molecule–substrate contact, the b-axis aligned along [110]KCl and [1–10]KCl. Growth at elevated temperatures enabled changes in the crystal growth whereby more defined structures formed on NaCl. On KCl, the bird-like structures remained very similar, while caffeine on the mica surface at elevated temperatures resulted in even additional texture forming with the caffeine molecules now also favoring a flat-on orientation with respect to the surface. The systematic variation of various system parameters demonstrates how sensitive the growth behavior of caffeine on this variety of substrates is.
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Affiliation(s)
- Christian Röthel
- Institute of Pharmaceutical Sciences , Department of Pharmaceutical Technology , Karl-Franzens Universität Graz , Universitätsplatz 1 , 8010 Graz , Austria . ; .,Institute of Solid State Physics , Graz University of Technology , Petersgasse 16 , 8010 Graz , Austria
| | - Michal Radziown
- Institute of Semiconductor and Solid State Physics , Johannes Kepler Universität Linz , Altenbergerstraße 69 , 4040 Linz , Austria
| | - Roland Resel
- Institute of Solid State Physics , Graz University of Technology , Petersgasse 16 , 8010 Graz , Austria.,BioTechMed - Graz , Austria
| | - Andreas Grois
- Institute of Solid State Physics , Graz University of Technology , Petersgasse 16 , 8010 Graz , Austria
| | - Clemens Simbrunner
- Institute of Solid State Physics , Graz University of Technology , Petersgasse 16 , 8010 Graz , Austria.,Institute of Solid State Physics , University of Bremen , Otto-Hahn-Allee 1 , 28359 Bremen , Germany
| | - Oliver Werzer
- Institute of Pharmaceutical Sciences , Department of Pharmaceutical Technology , Karl-Franzens Universität Graz , Universitätsplatz 1 , 8010 Graz , Austria . ; .,BioTechMed - Graz , Austria
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11
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Simbrunner C, Schwabegger G, Resel R, Dingemans T, Sitter H. The Epitaxial Growth of Self-Assembled Ternaphthalene Fibers on Muscovite Mica. CRYSTAL GROWTH & DESIGN 2014; 14:442-449. [PMID: 24526866 PMCID: PMC3919176 DOI: 10.1021/cg400912t] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 11/07/2013] [Indexed: 05/25/2023]
Abstract
The morphology and structure of 2,2':6',2″-ternaphthalene (NNN) deposited on muscovite mica(001) substrates was investigated by scanning force microscopy (SFM) and specular X-ray diffraction measurements. Consistently, both methods reveal the coexistence of needle-like structures with a {111} contact plane and {001} orientated island-like crystallites, which are built up by almost upright standing NNN molecules. Both orientations are characterized by a well-defined azimuthal alignment relative to the substrate surface, which is analyzed by X-ray diffraction pole figure (XRD-PF) measurements. Based on XRD-PF and SFM analysis, the azimuthal alignment of {001} orientated crystallites is explained by ledge-directed epitaxy along the fibers' sidewalls. These fibers are found to orient along two dominant directions, which is verified and explained by a doubling of the energetically preferred molecular adsorption site by mirror symmetry of the substrate surface. The experimental findings are confirmed by force-field simulations and are discussed based on a recently reported growth model.
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Affiliation(s)
- Clemens Simbrunner
- Institute
of Semiconductor and Solid State Physics, Johannes Kepler University, Altenbergerstrasse 69, A-4040 Linz, Austria
| | - Günther Schwabegger
- Institute
of Semiconductor and Solid State Physics, Johannes Kepler University, Altenbergerstrasse 69, A-4040 Linz, Austria
| | - Roland Resel
- Institute
of Solid State Physics, Graz University
of Technology, Petersgasse
16, A-8010 Graz, Austria
| | - Theo Dingemans
- Faculty
of Aerospace Engineering, Delft University
of Technology, 2629 HS Delft, The Netherlands
| | - Helmut Sitter
- Institute
of Semiconductor and Solid State Physics, Johannes Kepler University, Altenbergerstrasse 69, A-4040 Linz, Austria
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12
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Kjelstrup-Hansen J, Simbrunner C, Rubahn HG. Organic surface-grown nanowires for functional devices. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2013; 76:126502. [PMID: 24262288 DOI: 10.1088/0034-4885/76/12/126502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Discontinuous organic thin film growth on the surface of single crystals results in crystalline nanowires with extraordinary morphological and optoelectronic properties. By way of being generated at the interface of organic and inorganic materials, these nanowires combine the advantages of flexible organic films with the defectless character of inorganic crystalline substrates. The development of destruction-free transfer and direct growth methods allows one to integrate the organic nanowires into semiconductor, metallic electronic or photonic platforms. This article details the mechanisms that lead to the growth of these nanowires and exemplifies some of the linear as well as non-linear photonic properties, such as optical wave guiding, lasing and frequency conversion. The article also highlights future potential by showing that organic nanowires can be integrated into optoelectronic devices or hybrid photonic/plasmonic platforms as passive and active nanoplasmonic elements.
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13
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Schwabegger G, Oehzelt M, Salzmann I, Quochi F, Saba M, Mura A, Bongiovanni G, Vollmer A, Koch N, Sitter H, Simbrunner C. Interface properties of organic para-hexaphenyl/α-sexithiophene heterostructures deposited on highly oriented pyrolytic graphite. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:14444-14450. [PMID: 24156627 PMCID: PMC3842851 DOI: 10.1021/la402242b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 10/23/2013] [Indexed: 06/02/2023]
Abstract
It was recently reported, that heterostructures of para-hexaphenyl (p-6P) and α-sexithiophene (6T) deposited on muscovite mica exhibit the intriguing possibility to prepare lasing nanofibers of tunable emission wavelength. For p-6P/6T heterostructures, two different types of 6T emission have been observed, namely, the well-known red emission of bulk 6T crystals and additionally a green emission connected to the interface between p-6P and 6T. In this study, the origin of the green fluorescence is investigated by photoelectron spectroscopy (PES). As a prerequisite, it is necessary to prepare structurally similar organic crystals on a conductive surface, which leads to the choice of highly oriented pyrolytic graphite (HOPG) as a substrate. The similarity between p-6P/6T heterostructures on muscovite mica and on HOPG is evidenced by X-ray diffraction (XRD), scanning force microscopy (SFM), and optical spectroscopy. PES measurements show that the interface between p-6P and 6T crystals is sharp on a molecular level without any sign of interface dipole formation or chemical interaction between the molecules. We therefore conclude that the different emission colors of the two 6T phases are caused by different types of molecular aggregation.
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Affiliation(s)
- Günther Schwabegger
- Institute
of Semiconductor and Solid State Physics, Johannes Kepler University, Altenbergerstrasse 69, A-4040 Linz, Austria
| | - Martin Oehzelt
- Helmholtz
Zentrum Berlin für Materialien und Energie GmbH, BESSY II, D-12489 Berlin, Germany
- Institut
für Physik, Humboldt-Universität zu Berlin, D-12489 Berlin, Germany
| | - Ingo Salzmann
- Institut
für Physik, Humboldt-Universität zu Berlin, D-12489 Berlin, Germany
| | - Francesco Quochi
- Dipartimento
di Fisica, Università di Cagliari, I-09042 Monserrato
(CA), Italy
| | - Michele Saba
- Dipartimento
di Fisica, Università di Cagliari, I-09042 Monserrato
(CA), Italy
| | - Andrea Mura
- Dipartimento
di Fisica, Università di Cagliari, I-09042 Monserrato
(CA), Italy
| | - Giovanni Bongiovanni
- Dipartimento
di Fisica, Università di Cagliari, I-09042 Monserrato
(CA), Italy
- Istituto
Officina dei Materiali (CNR-IOM), Unità
di Cagliari, I-09042 Monserrato (CA), Italy
| | - Antje Vollmer
- Helmholtz
Zentrum Berlin für Materialien und Energie GmbH, BESSY II, D-12489 Berlin, Germany
| | - Norbert Koch
- Helmholtz
Zentrum Berlin für Materialien und Energie GmbH, BESSY II, D-12489 Berlin, Germany
- Institut
für Physik, Humboldt-Universität zu Berlin, D-12489 Berlin, Germany
| | - Helmut Sitter
- Institute
of Semiconductor and Solid State Physics, Johannes Kepler University, Altenbergerstrasse 69, A-4040 Linz, Austria
| | - Clemens Simbrunner
- Institute
of Semiconductor and Solid State Physics, Johannes Kepler University, Altenbergerstrasse 69, A-4040 Linz, Austria
- Dipartimento
di Fisica, Università di Cagliari, I-09042 Monserrato
(CA), Italy
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