1
|
Brown T, Blowey PJ, Sweetman A. Precise determination of molecular adsorption geometries by room temperature non-contact atomic force microscopy. Commun Chem 2024; 7:8. [PMID: 38184736 PMCID: PMC10771516 DOI: 10.1038/s42004-023-01093-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 12/20/2023] [Indexed: 01/08/2024] Open
Abstract
High resolution force measurements of molecules on surfaces, in non-contact atomic force microscopy, are often only performed at cryogenic temperatures, due to needing a highly stable system, and a passivated probe tip (typically via CO-functionalisation). Here we show a reliable protocol for acquiring three-dimensional force map data over both single organic molecules and assembled islands of molecules, at room temperature. Isolated cobalt phthalocyanine and islands of C60 are characterised with submolecular resolution, on a passivated silicon substrate (B:Si(111)-[Formula: see text]). Geometries of cobalt phthalocyanine are determined to a ~ 10 pm accuracy. For the C60, the protocol is sufficiently robust that areas spanning 10 nm × 10 nm are mapped, despite the difficulties of room temperature operation. These results provide a proof-of-concept for gathering high-resolution three-dimensional force maps of networks of complex, non-planar molecules on surfaces, in conditions more analogous to real-world application.
Collapse
|
2
|
Franz M, Chandola S, Koy M, Zielinski R, Aldahhak H, Das M, Freitag M, Gerstmann U, Liebig D, Hoffmann AK, Rosin M, Schmidt WG, Hogan C, Glorius F, Esser N, Dähne M. Controlled growth of ordered monolayers of N-heterocyclic carbenes on silicon. Nat Chem 2021; 13:828-835. [PMID: 34155377 DOI: 10.1038/s41557-021-00721-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 04/30/2021] [Indexed: 11/09/2022]
Abstract
N-Heterocyclic carbenes (NHCs) are promising modifiers and anchors for surface functionalization and offer some advantages over thiol-based systems. Because of their strong binding affinity and high electron donation, NHCs can dramatically change the properties of the surfaces to which they are bonded. Highly ordered NHC monolayers have so far been limited to metal surfaces. Silicon, however, remains the element of choice in semiconductor devices and its modification is therefore of utmost importance for electronic industries. Here, a comprehensive study on the adsorption of NHCs on silicon is presented. We find covalently bound NHC molecules in an upright adsorption geometry and demonstrate the formation of highly ordered monolayers exhibiting good thermal stability and strong work function reductions. The structure and ordering of the monolayers is controlled by the substrate geometry and reactivity and in particular by the NHC side groups. These findings pave the way towards a tailor-made organic functionalization of silicon surfaces and, thanks to the high modularity of NHCs, new electronic and optoelectronic applications.
Collapse
Affiliation(s)
- Martin Franz
- Institut für Festkörperphysik, Technische Universität Berlin, Berlin, Germany
| | - Sandhya Chandola
- Institut für Festkörperphysik, Technische Universität Berlin, Berlin, Germany.,Lehrstuhl für Theoretische Materialphysik, Universität Paderborn, Paderborn, Germany.,Helmholtz-Zentrum Berlin für Materialen und Energie GmbH, Berlin, Germany
| | - Maximilian Koy
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Robert Zielinski
- Institut für Festkörperphysik, Technische Universität Berlin, Berlin, Germany.,Leibniz-Institut für Analytische Wissenschaften - ISAS e.V., Berlin, Germany
| | - Hazem Aldahhak
- Lehrstuhl für Theoretische Materialphysik, Universität Paderborn, Paderborn, Germany
| | - Mowpriya Das
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Matthias Freitag
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Uwe Gerstmann
- Lehrstuhl für Theoretische Materialphysik, Universität Paderborn, Paderborn, Germany
| | - Denise Liebig
- Institut für Festkörperphysik, Technische Universität Berlin, Berlin, Germany
| | | | - Maximilian Rosin
- Institut für Festkörperphysik, Technische Universität Berlin, Berlin, Germany
| | - Wolf Gero Schmidt
- Lehrstuhl für Theoretische Materialphysik, Universität Paderborn, Paderborn, Germany
| | - Conor Hogan
- Istituto di Struttura della Materia-CNR (ISM-CNR), Rome, Italy.,Department of Physics, Università di Roma 'Tor Vergata', Rome, Italy
| | - Frank Glorius
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Münster, Germany.
| | - Norbert Esser
- Institut für Festkörperphysik, Technische Universität Berlin, Berlin, Germany. .,Leibniz-Institut für Analytische Wissenschaften - ISAS e.V., Berlin, Germany.
| | - Mario Dähne
- Institut für Festkörperphysik, Technische Universität Berlin, Berlin, Germany.
| |
Collapse
|
3
|
Geagea E, Jeannoutot J, Féron M, Palmino F, Thomas CM, Rochefort A, Chérioux F. Collective radical oligomerisation induced by an STM tip on a silicon surface. NANOSCALE 2021; 13:349-354. [PMID: 33346311 DOI: 10.1039/d0nr08291k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Over the past decade, on-surface fabrication of organic nanostructures has been widely investigated for the development of molecular electronic components, catalysts, and new materials. Here, we introduce a new strategy to obtain alkyl oligomers in a controlled manner using on-surface radical oligomerisations that are triggered by electrons between the tip of a scanning tunnelling microscope and the Si(111)√3 ×√3 R30°-B surface. This electron transfer event only occurs when the bias voltage is below -4.5 V and allows access to reactive radical species under exceptionally mild conditions. This transfer can effectively 'switch on' a sequence leading to the formation of oligomers of defined size distribution thanks to the on-surface confinement of the reactive species. Our approach enables new ways to initiate and control radical oligomerisations with tunnelling electrons, leading to molecularly precise nanofabrication.
Collapse
Affiliation(s)
- Elie Geagea
- Univ. Bourgogne Franche-Comte, FEMTO-ST, UFC, CNRS, 15B Avenue des Montboucons, F-25030 Besancon cedex, France.
| | | | | | | | | | | | | |
Collapse
|
4
|
Custovic I, Teyssieux D, Jeannoutot J, Lamare S, Palmino F, Abbasian H, Rochefort A, Chérioux F. Large-extended 2D supramolecular network of dipoles with parallel arrangement on a Si(111)-B surface. NANOSCALE 2020; 12:17399-17404. [PMID: 32789378 DOI: 10.1039/d0nr03372c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We have investigated the self-assembly of a strong dipolar molecule (LDipCC) on the semiconducting Si(111)-B surface with scanning tunneling microscopy (STM), density functional theory (DFT) calculations and STM simulations. Although the formation of an extended two-dimensional network was clearly revealed by STM under ultra-high vacuum, the assignment of a specific STM signature to the different terminal groups from the LDipCC molecular unit required a complete analysis by numerical simulations. The overall observed assembly is explained in terms of STM contrasts associated with the molecular structure of LDipCC and the molecule-surface interactions. To distinguish the relative arrangement of the dipolar molecules within the assembly, a rational combination of experimental results and electronic structure calculations allows us to identify a single adsorbed LDipCC phase in which the molecular dipoles are homogeneously arranged into a parallel fashion on the Si(111)-B surface.
Collapse
Affiliation(s)
- Irma Custovic
- Université Bourgogne Franche-Comté, FEMTO-ST, UFC, CNRS, 15 B Avenue des Montboucons, F-25030 Besançon, France.
| | | | | | | | | | | | | | | |
Collapse
|
5
|
Tan A, Zhang P. Tailoring the growth and electronic structures of organic molecular thin films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:503001. [PMID: 31422957 DOI: 10.1088/1361-648x/ab3c22] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
In the rapidly developing electronics industry, it has become increasingly necessary to explore materials that are cheap, flexible and versatile which have led to significant research efforts towards organic molecular thin films. Organic molecules are unique compared to their inorganic atomic counterparts as their properties can be tuned drastically through chemical functionalization, offering versatility, though their extended shape and weak intermolecular interactions bring significant challenges to the control of both the growth and the electronic structures of molecular thin films. In this paper, we will review the self-assembly process and how to establish long-range ordered organic molecular thin films. We will also discuss how the electronic structures of thin films are impacted by the molecule's local electrostatic environment and its interaction with the substrate, within the context of controlling interfacial energy level alignment between organic semiconductors and electrodes in electronic devices.
Collapse
Affiliation(s)
- Andrew Tan
- Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, United States of America
| | | |
Collapse
|
6
|
Amsterdam SH, Stanev TK, Zhou Q, Lou AJT, Bergeron H, Darancet P, Hersam MC, Stern NP, Marks TJ. Electronic Coupling in Metallophthalocyanine-Transition Metal Dichalcogenide Mixed-Dimensional Heterojunctions. ACS NANO 2019; 13:4183-4190. [PMID: 30848891 DOI: 10.1021/acsnano.8b09166] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Mixed-dimensional heterojunctions, such as zero-dimensional (0D) organic molecules deposited on two-dimensional (2D) transition metal dichalcogenides (TMDCs), often exhibit interfacial effects that enhance the properties of the individual constituent layers. Here we report a systematic study of interfacial charge transfer in metallophthalocyanine (MPc) - MoS2 heterojunctions using optical absorption and Raman spectroscopy to elucidate M core (M = first row transition metal), MoS2 layer number, and excitation wavelength effects. Observed phenomena include the emergence of heterojunction-specific optical absorption transitions and strong Raman enhancement that depends on the M identity. In addition, the Raman enhancement is tunable by excitation laser wavelength and MoS2 layer number, ultimately reaching a maximum enhancement factor of 30x relative to SiO2 substrates. These experimental results, combined with density functional theory (DFT) calculations, indicate strong coupling between nonfrontier MPc orbitals and the MoS2 band structure as well as charge transfer across the heterojunction interface that varies as a function of the MPc electronic structure.
Collapse
Affiliation(s)
- Samuel H Amsterdam
- Department of Chemistry and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
- Center for Light Energy Activated Redox Processes , Evanston , Illinois 60208 , United States
| | - Teodor K Stanev
- Department of Physics and Astronomy , Northwestern University , Evanston , Illinois 60208 , United States
| | - Qunfei Zhou
- Department of Materials Science and Engineering and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
- Center for Nanoscale Materials , Argonne National Laboratory , Lemont , Illinois 60439 , United States
| | - Alexander J-T Lou
- Department of Chemistry and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
| | - Hadallia Bergeron
- Department of Materials Science and Engineering and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
| | - Pierre Darancet
- Center for Nanoscale Materials , Argonne National Laboratory , Lemont , Illinois 60439 , United States
- Northwestern Argonne Institute for Science and Engineering , Evanston , Illinois 60208 , United States
| | - Mark C Hersam
- Department of Chemistry and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
- Center for Light Energy Activated Redox Processes , Evanston , Illinois 60208 , United States
- Department of Materials Science and Engineering and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
| | - Nathaniel P Stern
- Department of Physics and Astronomy , Northwestern University , Evanston , Illinois 60208 , United States
- Northwestern Argonne Institute for Science and Engineering , Evanston , Illinois 60208 , United States
| | - Tobin J Marks
- Department of Chemistry and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
- Center for Light Energy Activated Redox Processes , Evanston , Illinois 60208 , United States
- Department of Materials Science and Engineering and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
| |
Collapse
|
7
|
Matvija P, Rozbořil F, Sobotík P, Ošťádal I, Pieczyrak B, Jurczyszyn L, Kocán P. Electric-field-controlled phase transition in a 2D molecular layer. Sci Rep 2017; 7:7357. [PMID: 28779091 PMCID: PMC5544747 DOI: 10.1038/s41598-017-07277-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 06/23/2017] [Indexed: 11/25/2022] Open
Abstract
Self-assembly of organic molecules is a mechanism crucial for design of molecular nanodevices. We demonstrate unprecedented control over the self-assembly, which could allow switching and patterning at scales accessible by lithography techniques. We use the scanning tunneling microscope (STM) to induce a reversible 2D-gas-solid phase transition of copper phthalocyanine molecules on technologically important silicon surface functionalized by a metal monolayer. By means of ab-initio calculations we show that the charge transfer in the system results in a dipole moment carried by the molecules. The dipole moment interacts with a non-uniform electric field of the STM tip and the interaction changes the local density of molecules. To model the transition, we perform kinetic Monte Carlo simulations which reveal that the ordered molecular structures can form even without any attractive intermolecular interaction.
Collapse
Affiliation(s)
- Peter Matvija
- Faculty of Mathematics and Physics, Charles University, Prague, 121 16, Czech Republic.
| | - Filip Rozbořil
- Faculty of Mathematics and Physics, Charles University, Prague, 121 16, Czech Republic
| | - Pavel Sobotík
- Faculty of Mathematics and Physics, Charles University, Prague, 121 16, Czech Republic
| | - Ivan Ošťádal
- Faculty of Mathematics and Physics, Charles University, Prague, 121 16, Czech Republic
| | - Barbara Pieczyrak
- Instytut Fizyki Doswiadczalnej, Universytet Wroclawski, Wroclaw, 50-001, Poland
| | - Leszek Jurczyszyn
- Instytut Fizyki Doswiadczalnej, Universytet Wroclawski, Wroclaw, 50-001, Poland
| | - Pavel Kocán
- Faculty of Mathematics and Physics, Charles University, Prague, 121 16, Czech Republic
| |
Collapse
|
8
|
Olszowski P, Zajac L, Godlewski S, Such B, Pawlak R, Hinaut A, Jöhr R, Glatzel T, Meyer E, Szymonski M. Ordering of Zn-centered porphyrin and phthalocyanine on TiO 2(011): STM studies. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2017; 8:99-107. [PMID: 28144569 PMCID: PMC5238625 DOI: 10.3762/bjnano.8.11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 12/21/2016] [Indexed: 05/04/2023]
Abstract
Zn(II)phthalocyanine molecules (ZnPc) were thermally deposited on a rutile TiO2(011) surface and on Zn(II)meso-tetraphenylporphyrin (ZnTPP) wetting layers at room temperature and after elevated temperature thermal processing. The molecular homo- and heterostructures were characterized by high-resolution scanning tunneling microscopy (STM) at room temperature and their geometrical arrangement and degree of ordering are compared with the previously studied copper phthalocyanine (CuPc) and ZnTPP heterostructures. It was found that the central metal atom may play some role in ordering and growth of phthalocyanine/ZnTPP heterostructures, causing differences in stability of upright standing ZnPc versus CuPc molecular chains at given thermal annealing conditions.
Collapse
Affiliation(s)
- Piotr Olszowski
- Research Centre for Nanometer-Scale Science and Advanced Materials, NANOSAM, Faculty of Physics, Astronomy, and Applied Computer Science, Jagiellonian University, Lojasiewicza 11, 30-348 Krakow, Poland
| | - Lukasz Zajac
- Research Centre for Nanometer-Scale Science and Advanced Materials, NANOSAM, Faculty of Physics, Astronomy, and Applied Computer Science, Jagiellonian University, Lojasiewicza 11, 30-348 Krakow, Poland
| | - Szymon Godlewski
- Research Centre for Nanometer-Scale Science and Advanced Materials, NANOSAM, Faculty of Physics, Astronomy, and Applied Computer Science, Jagiellonian University, Lojasiewicza 11, 30-348 Krakow, Poland
| | - Bartosz Such
- Research Centre for Nanometer-Scale Science and Advanced Materials, NANOSAM, Faculty of Physics, Astronomy, and Applied Computer Science, Jagiellonian University, Lojasiewicza 11, 30-348 Krakow, Poland
| | - Rémy Pawlak
- University of Basel, Department of Physics, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Antoine Hinaut
- University of Basel, Department of Physics, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Res Jöhr
- University of Basel, Department of Physics, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Thilo Glatzel
- University of Basel, Department of Physics, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Ernst Meyer
- University of Basel, Department of Physics, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Marek Szymonski
- Research Centre for Nanometer-Scale Science and Advanced Materials, NANOSAM, Faculty of Physics, Astronomy, and Applied Computer Science, Jagiellonian University, Lojasiewicza 11, 30-348 Krakow, Poland
| |
Collapse
|
9
|
Liang Z, Sun H, Shen K, Hu J, Song B, Lu Y, Jiang Z, Song F. Unveiling orbital coupling at the CoPc/Bi(111) surface by ab initio calculations and photoemission spectroscopy. RSC Adv 2017. [DOI: 10.1039/c7ra09495g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Orbital coupling is revealed at the CoPc/Bi(111) interface with the local magnetic moment retained in CoPc.
Collapse
Affiliation(s)
- Zhaofeng Liang
- Shanghai Synchrotron Radiation Facility
- Shanghai Institute of Applied Physics
- Chinese Academy of Sciences
- China
- University of Chinese Academy of Sciences
| | - Haoliang Sun
- Shanghai Synchrotron Radiation Facility
- Shanghai Institute of Applied Physics
- Chinese Academy of Sciences
- China
- University of Chinese Academy of Sciences
| | - Kongchao Shen
- Shanghai Synchrotron Radiation Facility
- Shanghai Institute of Applied Physics
- Chinese Academy of Sciences
- China
| | - Jinbang Hu
- Shanghai Synchrotron Radiation Facility
- Shanghai Institute of Applied Physics
- Chinese Academy of Sciences
- China
| | - Bo Song
- University of Shanghai for Science and Technology
- Shanghai
- China
| | - Yunhao Lu
- College of Materials Science and Engineering
- Zhejiang University
- Hangzhou
- China
| | - Zheng Jiang
- Shanghai Synchrotron Radiation Facility
- Shanghai Institute of Applied Physics
- Chinese Academy of Sciences
- China
| | - Fei Song
- Shanghai Synchrotron Radiation Facility
- Shanghai Institute of Applied Physics
- Chinese Academy of Sciences
- China
| |
Collapse
|
10
|
Tan A, Wagner S, Zhang P. Self-assembly of F16ZnPc thin films and F16ZnPc-ZnPc heterostructures on deactivated Si surfaces studied by scanning tunneling microscopy. J Chem Phys 2016; 146:052809. [DOI: 10.1063/1.4967262] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Andrew Tan
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824-2320, USA
| | - Sean Wagner
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824-2320, USA
| | - Pengpeng Zhang
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824-2320, USA
| |
Collapse
|
11
|
Chen T, Foley BJ, Park C, Brown CM, Harriger LW, Lee J, Ruff J, Yoon M, Choi JJ, Lee SH. Entropy-driven structural transition and kinetic trapping in formamidinium lead iodide perovskite. SCIENCE ADVANCES 2016; 2:e1601650. [PMID: 27819055 PMCID: PMC5088641 DOI: 10.1126/sciadv.1601650] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 09/22/2016] [Indexed: 05/19/2023]
Abstract
A challenge of hybrid perovskite solar cells is device instability, which calls for an understanding of the perovskite structural stability and phase transitions. Using neutron diffraction and first-principles calculations on formamidinium lead iodide (FAPbI3), we show that the entropy contribution to the Gibbs free energy caused by isotropic rotations of the FA+ cation plays a crucial role in the cubic-to-hexagonal structural phase transition. Furthermore, we observe that the cubic-to-hexagonal phase transition exhibits a large thermal hysteresis. Our first-principles calculations confirm the existence of a potential barrier between the cubic and hexagonal structures, which provides an explanation for the observed thermal hysteresis. By exploiting the potential barrier, we demonstrate kinetic trapping of the cubic phase, desirable for solar cells, even at 8.2 K by thermal quenching.
Collapse
Affiliation(s)
- Tianran Chen
- Department of Physics, University of Virginia, Charlottesville, VA 22904, USA
| | - Benjamin J. Foley
- Department of Chemical Engineering, University of Virginia, Charlottesville, VA 22904, USA
| | - Changwon Park
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Craig M. Brown
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Leland W. Harriger
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Jooseop Lee
- Cornell High Energy Synchrotron Source, Cornell University, Ithaca, NY 14853, USA
| | - Jacob Ruff
- Cornell High Energy Synchrotron Source, Cornell University, Ithaca, NY 14853, USA
| | - Mina Yoon
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Joshua J. Choi
- Department of Chemical Engineering, University of Virginia, Charlottesville, VA 22904, USA
| | - Seung-Hun Lee
- Department of Physics, University of Virginia, Charlottesville, VA 22904, USA
| |
Collapse
|
12
|
Growing Ultra-flat Organic Films on Graphene with a Face-on Stacking via Moderate Molecule-Substrate Interaction. Sci Rep 2016; 6:28895. [PMID: 27356623 PMCID: PMC4928121 DOI: 10.1038/srep28895] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 06/10/2016] [Indexed: 11/13/2022] Open
Abstract
The electronic properties of small molecule organic crystals depend heavily on the molecular orientation. For multi-layer organic photovoltaics, it is desirable for the molecules to have a face-on orientation in order to enhance the out-of-plane transport properties. However, it is challenging to grow well-ordered and smooth films with a face-on stacking on conventional substrates such as metals and oxides. In this work, metal-phthalocyanine molecules is used as a model system to demonstrate that two-dimensional crystals such as graphene can serve as a template for growing high quality, ultra-flat organic films with a face-on orientation. Furthermore, the molecule-substrate interaction is varied systematically from strong to weak interaction regime with the interaction strength characterized by ultrafast electron transfer measurements. We find that in order to achieve the optimum orientation and morphology, the molecule-substrate interaction needs to be strong enough to ensure a face-on stacking while it needs to be weak enough to avoid film roughening.
Collapse
|
13
|
Zając Ł, Olszowski P, Godlewski S, Such B, Jöhr R, Pawlak R, Hinaut A, Glatzel T, Meyer E, Szymonski M. Ordered heteromolecular overlayers formed by metal phthalocyanines and porphyrins on rutile titanium dioxide surface studied at room temperature. J Chem Phys 2016; 143:224702. [PMID: 26671391 DOI: 10.1063/1.4936658] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Molecular heterostructures are formed from meso-tetraphenyl porphyrins-Zn(II) (ZnTPP) and Cu(II)-phthalocyanines (CuPc) on the rutile TiO2(011) surface. We demonstrate that ZnTPP molecules form a quasi-ordered wetting layer with flat-lying molecules, which provides the support for growth of islands comprised of upright CuPc molecules. The incorporation of the ZnTPP layer and the growth of heterostructures increase the stability of the system and allow for room temperature scanning tunneling microscopy (STM) measurements, which is contrasted with unstable STM probing of only CuPc species on TiO2. We demonstrate that within the CuPc layer the molecules arrange in two phases and we identify molecular dimers as basic building blocks of the dominant structural phase.
Collapse
Affiliation(s)
- Łukasz Zając
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, ul. S. Łojasiewicza 11, 30-348 Krakow, Poland
| | - Piotr Olszowski
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, ul. S. Łojasiewicza 11, 30-348 Krakow, Poland
| | - Szymon Godlewski
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, ul. S. Łojasiewicza 11, 30-348 Krakow, Poland
| | - Bartosz Such
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, ul. S. Łojasiewicza 11, 30-348 Krakow, Poland
| | - Res Jöhr
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Rémy Pawlak
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Antoine Hinaut
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Thilo Glatzel
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Ernst Meyer
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Marek Szymonski
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, ul. S. Łojasiewicza 11, 30-348 Krakow, Poland
| |
Collapse
|