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Shi Y, Liu J, Hu Y, Hu W, Jiang L. Effect of contact resistance in organic field‐effect transistors. NANO SELECT 2021. [DOI: 10.1002/nano.202000059] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Affiliation(s)
- Yanjun Shi
- Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology School of Petrochemical Engineering Changzhou University Changzhou China
- Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing China
| | - Jie Liu
- Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing China
| | - Yuanyuan Hu
- Key Laboratory for Micro‐Nano Optoelectronic Devices of Ministry of Education School of Physics and Electronics Hunan University Changsha China
| | - Wenping Hu
- College of Science Tianjin University Tianjin China
| | - Lang Jiang
- Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing China
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2
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Piranej S, Shelhart Sayers MAW, Deye GJ, Maximoff SN, Hopwood JP, Park H, Slavsky JG, Ciszek JW. Role of surface phenomena in the reaction of molecular solids: the Diels–Alder reaction on pentacene. CrystEngComm 2020. [DOI: 10.1039/d0ce00269k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reactivity trends for molecular solids cannot be explained exclusively through topochemical phenomenon (i.e. diffusivity, reaction cavities) or electronic structure of the molecules.
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Affiliation(s)
- Selma Piranej
- Department of Chemistry and Biochemistry
- Loyola University Chicago
- Chicago
- USA
| | | | - Gregory J. Deye
- Department of Chemistry and Biochemistry
- Loyola University Chicago
- Chicago
- USA
| | - Sergey N. Maximoff
- Department of Chemistry and Biochemistry
- Loyola University Chicago
- Chicago
- USA
| | | | - Haejun Park
- Department of Chemistry and Biochemistry
- Loyola University Chicago
- Chicago
- USA
| | - Jean G. Slavsky
- Department of Chemistry and Biochemistry
- Loyola University Chicago
- Chicago
- USA
| | - Jacob W. Ciszek
- Department of Chemistry and Biochemistry
- Loyola University Chicago
- Chicago
- USA
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3
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Un H, Wang J, Pei J. Recent Efforts in Understanding and Improving the Nonideal Behaviors of Organic Field-Effect Transistors. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2019; 6:1900375. [PMID: 31637154 PMCID: PMC6794634 DOI: 10.1002/advs.201900375] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 08/02/2019] [Indexed: 05/20/2023]
Abstract
Over the past three decades, the mobility of organic field-effect transistors (OFETs) has been improved from 10-5 up to over 10 cm2 V-1 s-1, which reaches or has already satisfied the requirements of demanding applications. However, pronounced nonideal behaviors in current-voltage characteristics are commonly observed, which indicates that the reported mobilities may not truly reflect the device properties. Herein, a comprehensive understanding of the origins of several observed nonidealities (downward, upward, double-slope, superlinear, and humped transfer characteristics) is summarized, and how to extract comparatively reliable mobilities from nonideal behaviors in OFETs is discussed. Combining an overview of the ideal and state-of-the-art OFETs, considerable possible approaches are also provided for future OFETs.
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Affiliation(s)
- Hio‐Ieng Un
- Beijing National Laboratory for Molecular Sciences (BNLMS)Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of EducationKey Laboratory of Polymer Chemistry and Physics of Ministry of EducationCenter of Soft Matter Science and EngineeringCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871China
| | - Jie‐Yu Wang
- Beijing National Laboratory for Molecular Sciences (BNLMS)Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of EducationKey Laboratory of Polymer Chemistry and Physics of Ministry of EducationCenter of Soft Matter Science and EngineeringCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871China
| | - Jian Pei
- Beijing National Laboratory for Molecular Sciences (BNLMS)Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of EducationKey Laboratory of Polymer Chemistry and Physics of Ministry of EducationCenter of Soft Matter Science and EngineeringCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871China
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4
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Li F, Ciszek JW. Reaction induced morphology changes of tetracene and pentacene surfaces. RSC Adv 2019; 9:26942-26948. [PMID: 35528549 PMCID: PMC9070438 DOI: 10.1039/c9ra05682c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 08/15/2019] [Indexed: 11/21/2022] Open
Abstract
Morphology plays a critical role in determining the properties of solid-state molecular materials, which necessitates a better understanding of its evolution when exposed to reactive conditions.
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Affiliation(s)
- Feifei Li
- Department of Chemistry and Biochemistry
- Loyola University Chicago
- Chicago
- USA
| | - Jacob W. Ciszek
- Department of Chemistry and Biochemistry
- Loyola University Chicago
- Chicago
- USA
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5
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Ravikumar A, Brivio GP, Fratesi G. Core Level Spectra of Organic Molecules Adsorbed on Graphene. MATERIALS (BASEL, SWITZERLAND) 2018; 11:ma11040518. [PMID: 29596315 PMCID: PMC5951364 DOI: 10.3390/ma11040518] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 03/27/2018] [Accepted: 03/27/2018] [Indexed: 06/08/2023]
Abstract
We perform first principle calculations based on density functional theory to investigate the effect of the adsorption of core-excited organic molecules on graphene. We simulate Near Edge X-ray absorption Fine Structure (NEXAFS) and X-ray Photoemission Spectroscopy (XPS) at the N and C edges for two moieties: pyridine and the pyridine radical on graphene, which exemplify two different adsorption characters. The modifications of molecular and graphene energy levels due to their interplay with the core-level excitation are discussed. We find that upon physisorption of pyridine, the binding energies of graphene close to the adsorption site reduce mildly, and the NEXAFS spectra of the molecule and graphene resemble those of gas phase pyridine and pristine graphene, respectively. However, the chemisorption of the pyridine radical is found to significantly alter these core excited spectra. The C 1s binding energy of the C atom of graphene participating in chemisorption increases by ∼1 eV, and the C atoms of graphene alternate to the adsorption site show a reduction in the binding energy. Analogously, these C atoms also show strong modifications in the NEXAFS spectra. The NEXAFS spectrum of the chemisorbed molecule is also modified as a result of hybridization with and screening by graphene. We eventually explore the electronic properties and magnetism of the system as a core-level excitation is adiabatically switched on.
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Affiliation(s)
- Abhilash Ravikumar
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via Cozzi, 55, 20125 Milano, Italy.
| | - Gian Paolo Brivio
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via Cozzi, 55, 20125 Milano, Italy.
| | - Guido Fratesi
- Dipartimento di Fisica, Università degli Studi di Milano, via Celoria, 16, 20133 Milano, Italy.
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6
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Casalini S, Bortolotti CA, Leonardi F, Biscarini F. Self-assembled monolayers in organic electronics. Chem Soc Rev 2018; 46:40-71. [PMID: 27722675 DOI: 10.1039/c6cs00509h] [Citation(s) in RCA: 220] [Impact Index Per Article: 36.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Self-assembly is possibly the most effective and versatile strategy for surface functionalization. Self-assembled monolayers (SAMs) can be formed on (semi-)conductor and dielectric surfaces, and have been used in a variety of technological applications. This work aims to review the strategy behind the design and use of self-assembled monolayers in organic electronics, discuss the mechanism of interaction of SAMs in a microscopic device, and highlight the applications emerging from the integration of SAMs in an organic device. The possibility of performing surface chemistry tailoring with SAMs constitutes a versatile approach towards the tuning of the electronic and morphological properties of the interfaces relevant to the response of an organic electronic device. Functionalisation with SAMs is important not only for imparting stability to the device or enhancing its performance, as sought at the early stages of development of this field. SAM-functionalised organic devices give rise to completely new types of behavior that open unprecedented applications, such as ultra-sensitive label-free biosensors and SAM/organic transistors that can be used as robust experimental gauges for studying charge tunneling across SAMs.
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Affiliation(s)
- Stefano Casalini
- Life Sciences Department, University of Modena and Reggio Emilia, Via Campi 103, 41125 Modena, Italy.
| | - Carlo Augusto Bortolotti
- Life Sciences Department, University of Modena and Reggio Emilia, Via Campi 103, 41125 Modena, Italy. and Consiglio Nazionale delle Ricerche (CNR), Institute for Nanosciences, Via Campi 213/a, 41125 Modena, Italy
| | - Francesca Leonardi
- Consiglio Nazionale delle Ricerche (CNR), Institute for Nanostructured Materials (ISMN), Via P. Gobetti 101, 40129 Bologna, Italy
| | - Fabio Biscarini
- Life Sciences Department, University of Modena and Reggio Emilia, Via Campi 103, 41125 Modena, Italy. and Consiglio Nazionale delle Ricerche (CNR), Institute for Nanostructured Materials (ISMN), Via P. Gobetti 101, 40129 Bologna, Italy
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7
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Deye GJ, Vicente JR, Dalke SM, Piranej S, Chen J, Ciszek JW. The Role of Thermal Activation and Molecular Structure on the Reaction of Molecular Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:8140-8146. [PMID: 28745890 DOI: 10.1021/acs.langmuir.7b02099] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Though surface modifications of organic thin films dramatically improve optoelectronic device performance, chemistry at organic surfaces presents new challenges that are not seen in conventional inorganic surfaces. This work demonstrates that the subsurface of pentacene remains highly accessible, even to large adsorbates, and that three distinct reaction regimes (surface, subsurface, and bulk) are accessed within the narrow thermal range of 30-75 °C. Progression of this transition is quantitatively measured via polarization modulation infrared reflection absorption spectroscopy, and atomic force microscopy is used to measure the thin-film morphology. Together, they reveal the close relationship between the extent of the reaction and the morphology changes. Finally, the reaction kinetics of the pentacene thin film is measured with a series of adsorbates that have different reactivity and diffusivity in the thin film. The results suggest that reaction kinetics in the thin film is controlled by both the reactivity and the adsorbate diffusivity in the thin-film lattice, which is very different than the traditional solution kinetics that is dominated by the chemical activation barriers. Combined, these experiments guide efforts toward rationally functionalizing the surfaces of organic semiconductors to enable the next generation of flexible devices.
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Affiliation(s)
- Gregory J Deye
- Department of Chemistry and Biochemistry, Loyola University Chicago , 1032 West Sheridan Road, Chicago, Illinois 60660, United States
| | - Juvinch R Vicente
- Department of Chemistry and Biochemistry, Ohio University , 100 University Terrace, Athens, Ohio 45701, United States
| | - Shawn M Dalke
- Department of Chemistry and Biochemistry, Loyola University Chicago , 1032 West Sheridan Road, Chicago, Illinois 60660, United States
| | - Selma Piranej
- Department of Chemistry and Biochemistry, Loyola University Chicago , 1032 West Sheridan Road, Chicago, Illinois 60660, United States
| | - Jixin Chen
- Department of Chemistry and Biochemistry, Ohio University , 100 University Terrace, Athens, Ohio 45701, United States
| | - Jacob W Ciszek
- Department of Chemistry and Biochemistry, Loyola University Chicago , 1032 West Sheridan Road, Chicago, Illinois 60660, United States
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8
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Noever SJ, Eder M, Del Giudice F, Martin J, Werkmeister FX, Hallwig S, Fischer S, Seeck O, Weber NE, Liewald C, Keilmann F, Turchanin A, Nickel B. Transferable Organic Semiconductor Nanosheets for Application in Electronic Devices. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1606283. [PMID: 28480616 DOI: 10.1002/adma.201606283] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Revised: 03/12/2017] [Indexed: 06/07/2023]
Abstract
A method has been developed to stabilize and transfer nanofilms of functional organic semiconductors. The method is based on crosslinking of their topmost layers by low energy electron irradiation. The films can then be detached from their original substrates and subsequently deposited onto new solid or holey substrates retaining their structural integrity. Grazing incidence X-ray diffraction, X-ray specular reflectivity, and UV-Vis spectroscopy measurements reveal that the electron irradiation of ≈50 nm thick pentacene films results in crosslinking of their only topmost ≈5 nm (3-4 monolayers), whereas the deeper pentacene layers preserve their pristine crystallinity. The electronic performance of the transferred pentacene nanosheets in bottom contact field-effect devices is studied and it is found that they are fully functional and demonstrate superior charge injection properties in comparison to the pentacene films directly grown on the contact structures by vapor deposition. The new approach paves the way to integration of the organic semiconductor nanofilms on substrates unfavorable for their direct growth as well as to their implementation in hybrid devices with unusual geometries, e.g., in devices incorporating free-standing sheets.
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Affiliation(s)
- Simon J Noever
- Faculty of Physics and CeNS, Ludwig-Maximilians-Universität München, 80539, Munich, Germany
- Nanosystems Initiative Munich (NIM), 80799, Munich, Germany
| | - Michael Eder
- Faculty of Physics and CeNS, Ludwig-Maximilians-Universität München, 80539, Munich, Germany
| | - Fabio Del Giudice
- Faculty of Physics and CeNS, Ludwig-Maximilians-Universität München, 80539, Munich, Germany
| | - Jan Martin
- Faculty of Physics and CeNS, Ludwig-Maximilians-Universität München, 80539, Munich, Germany
| | - Franz X Werkmeister
- Faculty of Physics and CeNS, Ludwig-Maximilians-Universität München, 80539, Munich, Germany
| | - Stefan Hallwig
- Faculty of Physics and CeNS, Ludwig-Maximilians-Universität München, 80539, Munich, Germany
| | - Stefan Fischer
- Faculty of Physics and CeNS, Ludwig-Maximilians-Universität München, 80539, Munich, Germany
| | - Oliver Seeck
- Deutsches Elektronen Synchrotron DESY, 22603, Hamburg, Germany
| | - Nils-Eike Weber
- Faculty of Physics, University of Bielefeld, 33615, Bielefeld, Germany
| | - Clemens Liewald
- Faculty of Physics and CeNS, Ludwig-Maximilians-Universität München, 80539, Munich, Germany
- Nanosystems Initiative Munich (NIM), 80799, Munich, Germany
| | - Fritz Keilmann
- Faculty of Physics and CeNS, Ludwig-Maximilians-Universität München, 80539, Munich, Germany
| | - Andrey Turchanin
- Institute of Physical Chemistry, Friedrich-Schiller-Universität Jena, 07743, Jena, Germany
- Jena Center for Soft Matter (JCSM), 07743, Jena, Germany
- Center for Energy and Environmental Chemistry (CEEC), 07743, Jena, Germany
- Abbe Center of Photonics (ACP), 07745, Jena, Germany
| | - Bert Nickel
- Faculty of Physics and CeNS, Ludwig-Maximilians-Universität München, 80539, Munich, Germany
- Nanosystems Initiative Munich (NIM), 80799, Munich, Germany
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9
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Piranej S, Turner DA, Dalke SM, Park H, Qualizza BA, Vicente J, Chen J, Ciszek JW. Tunable interfaces on tetracene and pentacene thin-films via monolayers. CrystEngComm 2016. [DOI: 10.1039/c6ce00728g] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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10
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Gim Y, Kang B, Kim B, Kim SG, Lee JH, Cho K, Ku BC, Cho JH. Atomically-thin molecular layers for electrode modification of organic transistors. NANOSCALE 2015; 7:14100-14108. [PMID: 26243510 DOI: 10.1039/c5nr03307a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Atomically-thin molecular layers of aryl-functionalized graphene oxides (GOs) were used to modify the surface characteristics of source-drain electrodes to improve the performances of organic field-effect transistor (OFET) devices. The GOs were functionalized with various aryl diazonium salts, including 4-nitroaniline, 4-fluoroaniline, or 4-methoxyaniline, to produce several types of GOs with different surface functional groups (NO2-Ph-GO, F-Ph-GO, or CH3O-Ph-GO, respectively). The deposition of aryl-functionalized GOs or their reduced derivatives onto metal electrode surfaces dramatically enhanced the electrical performances of both p-type and n-type OFETs relative to the performances of OFETs prepared without the GO modification layer. Among the functionalized rGOs, CH3O-Ph-rGO yielded the highest hole mobility of 0.55 cm(2) V(-1) s(-1) and electron mobility of 0.17 cm(2) V(-1) s(-1) in p-type and n-type FETs, respectively. Two governing factors: (1) the work function of the modified electrodes and (2) the crystalline microstructures of the benchmark semiconductors grown on the modified electrode surface were systematically investigated to reveal the origin of the performance improvements. Our simple, inexpensive, and scalable electrode modification technique provides a significant step toward optimizing the device performance by engineering the semiconductor-electrode interfaces in OFETs.
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Affiliation(s)
- Yuseong Gim
- SKKU Advanced Institute of Nanotechnology (SAINT), School of Chemical Engineering, Sungkyunkwan University, Suwon 440-746, Korea.
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11
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Zheng H, Asbahi M, Mukherjee S, Mathai CJ, Gangopadhyay K, Yang JKW, Gangopadhyay S. Room temperature Coulomb blockade effects in Au nanocluster/pentacene single electron transistors. NANOTECHNOLOGY 2015; 26:355204. [PMID: 26267227 DOI: 10.1088/0957-4484/26/35/355204] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Single-electron transistors incorporating single ∼1 nm gold nanocluster (AuNCs) and pentacene as a complex charge transport system have been used to study the quantum Coulomb blockade and its single electron tunnelling behaviour at room temperature (RT) (300 K). Monodisperse ultra-small (0.86 ± 0.30 nm) AuNCs were deposited by the tilted-target sputtering technique into 12 nm nanogaps fabricated by high-resolution e-beam lithography. Tunnelling resistance was modulated to ∼10(9) Ω by addition of a pentacene layer, allowing clear observation of quantum staircases and Coulomb oscillations with on/off current modulation ratio of ∼100 in RT current-voltage measurements. The electron addition energy and average quantized energy level spacing were found to be 282 and 80.4 meV, respectively, which are significantly larger than the thermal energy at 300 K (25.9 meV).
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Affiliation(s)
- Haisheng Zheng
- Department of Electrical and Computer Engineering, University of Missouri Columbia, MO 65211, USA
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12
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Frątczak E, Uznański P, Moneta M. Characterization of molecular organization in pentacene thin films on SiO2 surface using infrared spectroscopy, spectroscopic ellipsometry, and atomic force microscopy. Chem Phys 2015. [DOI: 10.1016/j.chemphys.2015.04.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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13
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Ahmad S. Organic semiconductors for device applications: current trends and future prospects. JOURNAL OF POLYMER ENGINEERING 2014. [DOI: 10.1515/polyeng-2013-0267] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
With the rich experience of developing silicon devices over a period of the last six decades, it is easy to assess the suitability of a new material for device applications by examining charge carrier injection, transport, and extraction across a practically realizable architecture; surface passivation; and packaging and reliability issues besides the feasibility of preparing mechanically robust wafer/substrate of single-crystal or polycrystalline/amorphous thin films. For material preparation, parameters such as purification of constituent materials, crystal growth, and thin-film deposition with minimum defects/disorders are equally important. Further, it is relevant to know whether conventional semiconductor processes, already known, would be useable directly or would require completely new technologies. Having found a likely candidate after such a screening, it would be necessary to identify a specific area of application against an existing list of materials available with special reference to cost reduction considerations in large-scale production. Various families of organic semiconductors are reviewed here, especially with the objective of using them in niche areas of large-area electronic displays, flexible organic electronics, and organic photovoltaic solar cells. While doing so, it appears feasible to improve mobility and stability by adjusting π-conjugation and modifying the energy band-gap. Higher conductivity nanocomposites, formed by blending with chemically conjugated C-allotropes and metal nanoparticles, open exciting methods of designing flexible contact/interconnects for organic and flexible electronics as can be seen from the discussion included here.
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14
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Tseng CW, Huang DC, Tao YT. Azobenzene-functionalized gold nanoparticles as hybrid double-floating-gate in pentacene thin-film transistors/memories with enhanced response, retention, and memory windows. ACS APPLIED MATERIALS & INTERFACES 2013; 5:9528-9536. [PMID: 24025199 DOI: 10.1021/am4023253] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Gold nanoparticles (Au-NPs) with surfaces covered with a self-assembled monolayer of azobenzene derivatives were prepared at the interface of dielectric insulator SiO2 and pentacene thin film. Transistors constructed with these composite channel materials exhibited electric bistability upon different gate biases, with the monolayer serving as a barrier layer, a work function modulator, as well as additional charge trapping sites at the Au-NPs/semiconductor interface at the same time. In comparison with simple alkanethiol monolayer-covered Au-NPs, the CH3-substituted azobenzene-functionalized Au-NPs result in a transistor memory device with about 70% more charges trapped, much faster response time as well as higher retention time. Besides, depending on the substituent on the azobenzene moieties (CH3, H, or CF3) and the tethering alkyl chain length, the speed at which the carriers are trapped (affecting switching response) and the stability of the carriers that are trapped (affecting memory retention) can be modulated to improve the device performance. The structural characterization and electronic characteristics of these devices will be detailed.
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15
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Nakabayashi S, Shinozaki R, Senda Y, Yoshikawa HY. Hydrogen nanobubble at normal hydrogen electrode. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:184008. [PMID: 23598899 DOI: 10.1088/0953-8984/20/18/184008] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Electrochemically formed hydrogen nanobubbles at a platinum rotating disk electrode (RDE) were detected by re-oxidation charge. The dissolution time course of the hydrogen nanobubbles was measured by AFM tapping topography under open-circuit conditions at stationary platinum and gold single-crystal electrodes. The bubble dissolution at platinum was much faster than that at gold because two types of diffusion, bulk and surface diffusion, proceeded at the platinum surface, whereas surface diffusion was prohibited at the gold electrode. These findings indicated that the electrochemical reaction of normal hydrogen electrode partly proceeded heterogeneously on the three-phase boundary around the hydrogen nanobubble.
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Affiliation(s)
- S Nakabayashi
- Department of Chemistry, Faculty of Science, Saitama University, Sakura-ku, Shimo-okubo, 225, Saitama 338-8570, Japan
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16
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Claridge SA, Liao WS, Thomas JC, Zhao Y, Cao H, Cheunkar S, Serino AC, Andrews AM, Weiss PS. From the bottom up: dimensional control and characterization in molecular monolayers. Chem Soc Rev 2013; 42:2725-45. [PMID: 23258565 PMCID: PMC3596502 DOI: 10.1039/c2cs35365b] [Citation(s) in RCA: 135] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Self-assembled monolayers are a unique class of nanostructured materials, with properties determined by their molecular lattice structures, as well as the interfaces with their substrates and environments. As with other nanostructured materials, defects and dimensionality play important roles in the physical, chemical, and biological properties of the monolayers. In this review, we discuss monolayer structures ranging from surfaces (two-dimensional) down to single molecules (zero-dimensional), with a focus on applications of each type of structure, and on techniques that enable characterization of monolayer physical properties down to the single-molecule scale.
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Affiliation(s)
- Shelley A. Claridge
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
- Department of Chemistry & Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Wei-Ssu Liao
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
- Department of Chemistry & Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - John C. Thomas
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
- Department of Chemistry & Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Yuxi Zhao
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
- Department of Chemistry & Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Huan Cao
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
- Department of Chemistry & Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Sarawut Cheunkar
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
- Department of Chemistry & Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Andrew C. Serino
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
- Department of Chemistry & Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Anne M. Andrews
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
- Department of Chemistry & Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
- Department of Psychiatry, University of California, Los Angeles, Los Angeles, California 90095, United States
- Semel Institute for Neuroscience & Human Behavior, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Paul S. Weiss
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
- Department of Chemistry & Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
- Department of Materials Science & Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
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17
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Ma H, Acton O, Hutchins DO, Cernetic N, Jen AKY. Multifunctional phosphonic acid self-assembled monolayers on metal oxides as dielectrics, interface modification layers and semiconductors for low-voltage high-performance organic field-effect transistors. Phys Chem Chem Phys 2013; 14:14110-26. [PMID: 22767209 DOI: 10.1039/c2cp41557g] [Citation(s) in RCA: 128] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Insulating and semiconducting molecular phosphonic acid (PA) self-assembled monolayers (SAMs) have been developed for applications in organic field-effect transistors (OFETs) for low-power, low-cost flexible electronics. Multifunctional SAMs on ultrathin metal oxides, such as hafnium oxide and aluminum oxide, are shown to enable (1) low-voltage (sub 2 V) OFETs through dielectric and interface engineering on rigid and plastic substrates, (2) simultaneous one-component modification of source-drain and dielectric surfaces in bottom-contact OFETs, and (3) SAM-FETs based on molecular monolayer semiconductors. The combination of excellent dielectric and interfacial properties results in high-performance OFETs with low-subthreshold slopes down to 75 mV dec(-1), high I(on)/I(off) ratios of 10(5)-10(7), contact resistance down to 700 Ω cm, charge carrier mobilities of 0.1-4.6 cm(2) V(-1) s(-1), and general applicability to solution-processed and vacuum-deposited n-type and p-type organic and polymer semiconductors.
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Affiliation(s)
- Hong Ma
- Department of Materials Science and Engineering, University of Washington, Seattle, 98195, USA.
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Hiszpanski AM, Lee SS, Wang H, Woll AR, Nuckolls C, Loo YL. Post-deposition processing methods to induce preferential orientation in contorted hexabenzocoronene thin films. ACS NANO 2013; 7:294-300. [PMID: 23228001 DOI: 10.1021/nn304003u] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The structuring in organic electrically active thin films critically influences the performance of devices comprising them. Controlling film structure, however, remains challenging and generally requires stringent deposition conditions or modification of the substrate. To this end, we have developed post-deposition processing methods that are decoupled from the initial deposition conditions to induce different out-of-plane molecular orientations in contorted hexabenzocoronene (HBC) thin films. As-deposited HBC thin films lack any long-range order; subjecting them to post-deposition processing, such as hexanes-vapor annealing, thermal annealing, and physical contact with elastomeric poly(dimethyl siloxane), induces crystallization with increasing extents of preferential edge-on orientation, corresponding to greater degrees of in-plane π-stacking. Accordingly, transistors comprising HBC thin films that have been processed under these conditions exhibit field-effect mobilities that increase by as much as 2 orders of magnitude with increasing extents of molecular orientation. The ability to decouple HBC deposition from its subsequent structuring through post-deposition processing affords us the unique opportunity to tune competing molecule-molecule and molecule-solvent interactions, which ultimately leads to control over the structure and electrical function of HBC films.
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Affiliation(s)
- Anna M Hiszpanski
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
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Chao TH, Chang MJ, Watanabe M, Luo MH, Chang YJ, Fang TC, Chen KY, Chow TJ. Solution processed high performance pentacene thin-film transistors. Chem Commun (Camb) 2012; 48:6148-50. [DOI: 10.1039/c2cc31754k] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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20
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Muccioli L, D'Avino G, Zannoni C. Simulation of vapor-phase deposition and growth of a pentacene thin film on C60 (001). ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2011; 23:4532-4536. [PMID: 21901761 DOI: 10.1002/adma.201101652] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 07/06/2011] [Indexed: 05/31/2023]
Affiliation(s)
- Luca Muccioli
- Dipartimento di Chimica Fisica e Inorganica and INSTM, University of Bologna, viale Risorgimento 4, IT-40136 Bologna, Italy.
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Cantrell RA, James C, Clancy P. Computationally derived rules for persistence of C60 nanowires on recumbent pentacene bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:9944-9954. [PMID: 21732668 DOI: 10.1021/la201576z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The tendency for C(60) nanowires to persist on two monolayers of recumbent pentacene is studied using molecular dynamics (MD) simulations. A review of existing experimental literature for the tilt angle adopted by pentacene on noble metal surfaces shows that studies cover a limited range from 55° to 90°, motivating simulation studies of essentially the entire range of tilt angles (10°-90°) to predict the optimum surface tilt angle for C(60) nanowire formation. The persistence of a 1D nanowire depends sensitively on this tilt angle, the amount of initial tensile strain, and the presence of surface step edges. At room temperature, C(60) nanowires oriented along the pentacene short axes persist for several nanoseconds and are more likely to occur if they reside between, or within, pentacene rows for ϕ ≤ ∼60°. The likelihood of this persistence increases the smaller the tilt angle. Nanowires oriented along the long axes of pentacene molecules are unlikely to form. The limit of stability of nanowires was tested by raising the temperature to 400 K. Nanowires located between pentacene rows survived this temperature rise, but those located initially within pentacene rows are only stable in the range ϕ(1) = 30°-50°. Flatter pentacene surfaces, that is, tilt angles above about 60°, are subject to disorder caused by C(60) molecules "burrowing" into the pentacene surface. An initial strain of 5% applied to the C(60) nanowires significantly decreases the likelihood of nanowire persistence. In contrast, any appreciable surface roughness, even by half a monolayer in height of a third pentacene monolayer, strongly enhances the likelihood of nanowire formation due to the strong binding energy of C(60) molecules to step edges.
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Affiliation(s)
- Rebecca A Cantrell
- Department of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
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Lou JL, Shiu HW, Chang LY, Wu CP, Soo YL, Chen CH. Preparation and characterization of an ordered 1-dodecanethiol monolayer on bare Si(111) surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:3436-41. [PMID: 21401112 DOI: 10.1021/la103585t] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
We have grown 1-dodecandthiol (DDT) monolayer on a bare Si(111) surface through ultraviolet-assisted photochemical reaction. The resulting monolayer was investigated by means of water contact angle measurement, synchrotron radiation-based high-resolution X-ray photoelectron spectroscopy, and polarization-dependent near-edge X-ray absorption fine structure spectroscopy. These combined probes for characterization reveal a hydrophobic ambient surface; the DDT was directly attached to Si through a Si-S bond, and the molecules formed an ordered monolayer with an average tilt angle of 57° of the alkyl chains relative to the substrate surface.
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Affiliation(s)
- Jie Ling Lou
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
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McCarthy MA, Liu B, Jayaraman R, Gilbert SM, Kim DY, So F, Rinzler AG. Reorientation of the high mobility plane in pentacene-based carbon nanotube enabled vertical field effect transistors. ACS NANO 2011; 5:291-298. [PMID: 21141982 DOI: 10.1021/nn102721v] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The large current densities attained by carbon nanotube enabled vertical field effect transistors using crystalline organic channel materials are somewhat unexpected given the known large anisotropy in the mobility of crystalline organics and their conventional ordering on dielectric surfaces which tends to orient their high mobility axes parallel to the surface. This seeming contradiction is resolved by the finding that the nanotubes induce a molecular ordering that reorients the high mobility axes to favor current flow in a direction perpendicular to the substrate surface.
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Affiliation(s)
- Mitchell A McCarthy
- Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611, United States
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DeLongchamp DM, Kline RJ, Fischer DA, Richter LJ, Toney MF. Molecular characterization of organic electronic films. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2011; 23:319-37. [PMID: 20809510 DOI: 10.1002/adma.201001760] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Indexed: 05/23/2023]
Abstract
Organic electronics have emerged as a viable competitor to amorphous silicon for the active layer in low-cost electronics. The critical performance of organic electronic materials is closely related to their morphology and molecular packing. Unlike their inorganic counterparts, polymers combine complex repeat unit structure and crystalline disorder. This combination prevents any single technique from being able to uniquely solve the packing arrangement of the molecules. Here, a general methodology for combining multiple, complementary techniques that provide accurate unit cell dimensions and molecular orientation is described. The combination of measurements results in a nearly complete picture of the organic film morphology.
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Affiliation(s)
- Dean M DeLongchamp
- Polymers Division, National Institute of Standards and Technology, Gaithersburg, MD 20899-8541, USA.
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Shao W, Dong H, Jiang L, Hu W. Morphology control for high performance organic thin film transistors. Chem Sci 2011. [DOI: 10.1039/c0sc00502a] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Becerril HA, Stoltenberg RM, Tang ML, Roberts ME, Liu Z, Chen Y, Kim DH, Lee BL, Lee S, Bao Z. Fabrication and evaluation of solution-processed reduced graphene oxide electrodes for p- and n-channel bottom-contact organic thin-film transistors. ACS NANO 2010; 4:6343-6352. [PMID: 20945927 DOI: 10.1021/nn101369j] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Reduced graphene oxide (RGO) is an electrically conductive carbon-based nanomaterial that has recently attracted attention as a potential electrode for organic electronics. Here we evaluate several solution-based methods for fabricating RGO bottom-contact (BC) electrodes for organic thin-film transistors (OTFTs), demonstrate functional p- and n-channel devices with such electrodes, and compare their electrical performance with analogous devices containing gold electrodes. We show that the morphology of organic semiconductor films deposited on RGO electrodes is similar to that observed in the channel region of the devices and that devices fabricated with RGO electrodes have lower contact resistances compared to those fabricated with gold contacts. Although the conductivity of RGO is poor compared to that of gold, RGO is still an enticing electrode material for organic electronic devices possibly owing to the retention of desirable morphological features, lower contact resistance, lower cost, and solution processability.
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Affiliation(s)
- Hector A Becerril
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
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Tseng CW, Tao YT. Organic field-effect transistor/memory devices with pentacene/polydiacetylene composite film as active channel material: a morphology dependence study. ACS APPLIED MATERIALS & INTERFACES 2010; 2:3231-3240. [PMID: 21028840 DOI: 10.1021/am100696v] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Composite films of pentacene and poly(10,12-pentacosadiynoic acid) were prepared and used as the active channel material in a top-contact, bottom-gate field-effect transistor. The transistors exhibited high field-effect mobility as well as large I-V hysteresis as a function of gate bias history. The polydiacetylenic moieties incorporated in the pentacene film served as charge storage vehicles, which affected the threshold voltage shifts and created the electric bistability needed in a memory device. The memory window, response, and retention highly depend on the morphology of the polydiacetylene film buried under. Detailed film structure analyses and correlation with the transistor/memory property are provided.
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28
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1,7-Dinitroperylene bisimides: facile synthesis and characterization as n-type organic semiconductors. Tetrahedron Lett 2010. [DOI: 10.1016/j.tetlet.2010.09.029] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Salleo A, Kline RJ, DeLongchamp DM, Chabinyc ML. Microstructural characterization and charge transport in thin films of conjugated polymers. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2010; 22:3812-3838. [PMID: 20607787 DOI: 10.1002/adma.200903712] [Citation(s) in RCA: 271] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The performance of semiconducting polymers has been steadily increasing in the last 20 years. Improved control over the microstructure of these materials and a deeper understanding of how the microstructure affects charge transport are partially responsible for such trend. The development and widespread use of techniques that allow to characterize the microstructure of semiconducting polymers is therefore instrumental for the advance of these materials. This article is a review of the characterization techniques that provide information used to enhance the understanding of structure/property relationships in semiconducting polymers. In particular, the applications of optical and X-ray spectroscopy, X-ray diffraction, and scanning probe techniques in this context are described.
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Affiliation(s)
- Alberto Salleo
- Materials Science and Engineering, Stanford, CA 94305, USA.
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30
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Miozzo L, Yassar A, Horowitz G. Surface engineering for high performance organic electronic devices: the chemical approach. ACTA ACUST UNITED AC 2010. [DOI: 10.1039/b922385a] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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31
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Wang ZH, Käfer D, Bashir A, Götzen J, Birkner A, Witte G, Wöll C. Influence of OH groups on charge transport across organic–organic interfaces: a systematic approach employing an “ideal” device. Phys Chem Chem Phys 2010; 12:4317-23. [DOI: 10.1039/b924230a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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32
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Yun DJ, Rhee SW. Effect of self assembled monolayer on the energy structure of pentacene and Ru/Ti semiconductor–metal contact measured with in situ ultraviolet photoemission spectroscopy. ACTA ACUST UNITED AC 2010. [DOI: 10.1039/c0jm01710h] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
AbstractSelf-assembled monolayers (SAMs) of ω-(4′-methylbiphenyl-4-yl)ethanethiol (CH3(C6H4)2(CH2)2SH, BP2) prepared at different temperatures on Au(111) substrates were investigated using scanning tunneling microscopy (STM). Also, the effect of the incubation time of the gold substrate in the thiol solution was examined. The STM results showed that samples prepared at room temperature were significantly different from those prepared at elevated temperatures in their surface morphology, space group and size of unit cell. The micrographs of samples prepared at higher temperatures revealed a pronounced and progressive increase in the size of the well-known etch-pits at the expense of their density with increasing preparation temperature (but the increase did not continue for SAMs prepared at 348 K). The average domain size was found to increase significantly with increasing preparation temperature. In addition, polymorphism was observed in BP2 SAMs at all investigated temperatures. This study has demonstrated that solution temperature and incubation time are key factors controlling the two-dimensional SAM structure of BP2 molecules.
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Tseng CW, Tao YT. Electric Bistability in Pentacene Film-Based Transistor Embedding Gold Nanoparticles. J Am Chem Soc 2009; 131:12441-50. [DOI: 10.1021/ja904882m] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Chiao-Wei Tseng
- Institute of Chemistry, Academia Sinica, Taipei, Taiwan, Republic of China 115 and Department of Chemistry, National Tsing-Hua University, Hsinchu, Taiwan, Republic of China, 115
| | - Yu-Tai Tao
- Institute of Chemistry, Academia Sinica, Taipei, Taiwan, Republic of China 115 and Department of Chemistry, National Tsing-Hua University, Hsinchu, Taiwan, Republic of China, 115
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35
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Cavallini M. Inhomogeneous thin deposits: a strategy to exploit their functionality. ACTA ACUST UNITED AC 2009. [DOI: 10.1039/b903569a] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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36
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Effect of HAuCl[sub 4] Doping on the Contact Properties of Polymer Thin-Film Transistors. ACTA ACUST UNITED AC 2009. [DOI: 10.1149/1.3152571] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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37
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Olive AGL, Guerzo A, Belin C, Reichwagen J, Hopf H, Desvergne JP. Self-assembly of soluble anthracene, tetracene and pentacene derivatives. RESEARCH ON CHEMICAL INTERMEDIATES 2008. [DOI: 10.1163/156856708783623410] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Rhee SW, Yun DJ. Metal–semiconductor contact in organic thin film transistors. ACTA ACUST UNITED AC 2008. [DOI: 10.1039/b805884a] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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41
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Hu WS, Weng SZ, Tao YT, Liu HJ, Lee HY, Fan LJ, Yang YW. Oriented growth of crystalline pentacene films with preferred a-b in-plane alignment on a rubbed crystalline polymethylene surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:12901-12909. [PMID: 18020385 DOI: 10.1021/la7027065] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We have achieved a growth of highly oriented crystalline pentacene thin films, with preferred a-b in-plane orientation with respect to the rubbing direction of a rubbed polymethylene surface. The polymethylene thin film, generated on a gold surface by gold-catalyzed decomposition of diazomethane, was annealed and gently rubbed in a fixed direction by a flannelette cloth to serve as an alignment layer during the deposition of pentacene molecules. Various surface analysis techniques, including reflection absorption IR spectroscopy (RAIRS), near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, grazing incidence X-ray diffraction (GIXD), and atomic force microscopy were used to elucidate the structural details of the polymethylene and the pentacene thin films deposited on it. Two crystalline morphologies of pentacene thin film were observed: the minor one of rod-like molecular crystals having their long axes of the crystals perpendicular to the rubbing direction, and the dominant one of platelet-like and layered crystals having the molecular axes stand near vertical to the surface. Moreover, GIXD revealed that the rubbing on polymethylene indeed induced a preferential azimuthal alignment of pentacene crystallites. The deposition of pentacene at 25 degrees C led to a twin growth of crystallites with the [110] direction predominately aligned perpendicular to the rubbing direction. In contrast, the pentacene deposition at 50 degrees C produced twinned crystallites of lower twin angle and the [120] direction aligned parallel to the rubbing direction.
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Affiliation(s)
- Wei-Shan Hu
- Institute of Chemistry, Academia Sinica, Taipei, 115, Taiwan, Republic of China
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Betti MG, Kanjilal A, Mariani C. Electronic States of a Single Layer of Pentacene: Standing-Up and Flat-Lying Configurations. J Phys Chem A 2007; 111:12454-7. [DOI: 10.1021/jp074365i] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Maria Grazia Betti
- Dipartimento di Fisica, Università di Roma “La Sapienza”, Piazzale Aldo Moro 2, I-00185 Roma, Italy, and INFM-CNR Center on nanoStructures and bioSystems at Surfaces (S∧3), Via G. Campi 231/A, I-41100 Modena, Italy
| | - Aloke Kanjilal
- Dipartimento di Fisica, Università di Roma “La Sapienza”, Piazzale Aldo Moro 2, I-00185 Roma, Italy, and INFM-CNR Center on nanoStructures and bioSystems at Surfaces (S∧3), Via G. Campi 231/A, I-41100 Modena, Italy
| | - Carlo Mariani
- Dipartimento di Fisica, Università di Roma “La Sapienza”, Piazzale Aldo Moro 2, I-00185 Roma, Italy, and INFM-CNR Center on nanoStructures and bioSystems at Surfaces (S∧3), Via G. Campi 231/A, I-41100 Modena, Italy
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Zheng Y, Qi D, Chandrasekhar N, Gao X, Troadec C, Wee ATS. Effect of molecule-substrate interaction on thin-film structures and molecular orientation of pentacene on silver and gold. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:8336-42. [PMID: 17602678 DOI: 10.1021/la063165f] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Evaporated pentacene thin films with thicknesses from several nm to 150 nm on gold and silver substrates have been studied by ultraviolet photoelectron spectroscopy (UPS), near-edge X-ray absorption fine structure (NEXAFS), scanning tunneling microscopy (STM), and atomic force microscopy (AFM). It was found that pentacene thin-film structures, particularly their molecular orientations, are strongly influenced by the metal substrates. UPS measurements revealed a distinct change in the valence band structures of pentacene on Au compared to those on Ag, which is attributed to the different packing between adjacent molecules. Using NEXAFS, we observed 74+/-5 degrees and 46+/-5 degrees molecular tilt angles on Ag and Au, respectively, for all measured thicknesses. We propose that pentacene molecules stand up on the surface and form the "thin-film phase" structure on Ag. On Au, pentacene films grow in domains with molecules either lying flat or standing up on the substrate. Such a mixture of two crystalline phases leads to an average tilt angle of 46 degrees for the whole film and the change in valence band structures. STM and distance-voltage (z-V) spectroscopy studies confirm the existence of two crystalline phases on Au with different conducting properties. z-V spectra on the low conducting phase clearly indicate its nature as "thin-film phase".
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Affiliation(s)
- Yi Zheng
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, and Institute of Material Research and Engineering (IMRE), 3 Research Link, Singapore 117602
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Chen KY, Hsieh HH, Wu CC, Hwang JJ, Chow TJ. A new type of soluble pentacene precursor for organic thin-film transistors. Chem Commun (Camb) 2007:1065-7. [PMID: 17325807 DOI: 10.1039/b616511g] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new type of soluble pentacene precursor is synthesized, which extrudes a unit of CO upon heating at 150 degrees C, to produce pentacene in nearly quantitative yield.
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Affiliation(s)
- Kew-Yu Chen
- Department of Chemistry, National Taiwan University, Taipei 106, Taiwan.
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Chen W, Huang C, Gao XY, Wang L, Zhen CG, Qi D, Chen S, Zhang HL, Loh KP, Chen ZK, Wee ATS. Tuning the Hole Injection Barrier at the Organic/Metal Interface with Self-Assembled Functionalized Aromatic Thiols. J Phys Chem B 2006; 110:26075-80. [PMID: 17181260 DOI: 10.1021/jp065821q] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Self-assembled functionalized aromatic thiols (oligophenylenes composed of building blocks of dimethoxy-substituted phenylenes, perfluoro-substituted phenylenes, and a terminal thiol group) were used to tune the hole injection barrier (Delta(h)) of copper(II) phthalocyanine (CuPc) on Au(111). Synchrotron-based high-resolution photoemission spectroscopy study reveals a significant reduction of Delta(h) by as much as 0.75 eV from Delta(h) = 0.9 eV for CuPc/Au(111) to Delta(h) = 0.15 eV for CuPc/BOF/Au(111), where BOF represents 4-pentafluorophenyl-1-(p-thiophenyl)-2,5-dimethoxybenzene. The delocalized pi orbitals of these functionalized aromatic thiols greatly facilitate effective charge transfer (hole or electron) across the SAM interface as compared to alkanethiols, hence making this novel interface modification scheme a simple and effective way to tune the hole injection barrier. This method has potential applications in molecular electronics, organic light-emitting diodes (OLED), organic field-effect transistors (OFETs), and organic solar cells.
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Affiliation(s)
- Wei Chen
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore
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46
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Balzer F, Kankate L, Niehus H, Frese R, Maibohm C, Rubahn HG. Tailoring the growth of p-6P nanofibres using ultrathin Au layers: an organic-metal-dielectric model system. NANOTECHNOLOGY 2006; 17:984-991. [PMID: 21727370 DOI: 10.1088/0957-4484/17/4/024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The influence of ultrathin Au cluster films on the growth of para-hexaphenyl (p-6P) fibres is investigated. Whereas p-6P at elevated temperatures forms long, mutually parallel fibres on plain mica, these fibres become shorter but taller on Au covered mica, up to a Au film thickness of approximately 8 nm. The degree to which fibres are mutually parallel decreases with increasing Au thickness. For thicker Au films the length of the fibres increases again, and their morphology changes from flat to faceted; for Au film thicknesses above 20 nm, fibre networks are formed. The spectroscopic properties of the fibres are not modified by the Au layer, enabling independent control of the fibre morphology by means of the intermediate metallic layer.
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Affiliation(s)
- Frank Balzer
- Humboldt-Universität zu Berlin, Institut für Physik/ASP, Newtonstraße 15, D-12489 Berlin, Germany
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Käfer D, Witte G, Cyganik P, Terfort A, Wöll C. A Comprehensive Study of Self-Assembled Monolayers of Anthracenethiol on Gold: Solvent Effects, Structure, and Stability. J Am Chem Soc 2006; 128:1723-32. [PMID: 16448148 DOI: 10.1021/ja0571592] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The formation and molecular structure of self-assembled monolayers (SAMs) of anthracene-2-thiol (AnT) on Au(111) have been characterized by reflection adsorption infrared spectroscopy, thermal desorption spectroscopy, X-ray photoelectron spectroscopy, near-edge X-ray absorption spectroscopy, scanning tunneling microscopy, and low energy electron diffraction. It is demonstrated that highly ordered monolayer films are formed upon immersion, but their quality depends critically on the choice of solvents and rinsing conditions. The saturated monolayer is characterized by a closed packed arrangement of upright standing molecules forming a (2 x 4)rect unit cell. At about 450 K a partial desorption takes place and the remaining molecules form a dilute (4 x 2)-phase with an almost planar adsorption geometry, while further heating above 520 K causes a thermally induced fragmentation. According to their different densities both phases reveal very diverse chemical reactivities. Whereas the saturated monolayer is stable and inert under ambient conditions, the dilute phase does not warrant any protection of the sulfur headgroups which oxidize rapidly in air.
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Affiliation(s)
- Daniel Käfer
- Physikalische Chemie I, Ruhr-Universität Bochum, 44780 Bochum, Germany
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Hu WS, Lin YF, Tao YT, Hsu YJ, Wei DH. Highly Oriented Growth of p-Sexiphenyl Molecular Nanocrystals on Rubbed Polymethylene Surface. Macromolecules 2005. [DOI: 10.1021/ma051298m] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Wei-Shan Hu
- Institute of Chemistry, Academia Sinica, Taipei,115, Taiwan, R.O.C., Department of Chemistry, National Tsing-Hua University, Hsin-chu, Taiwan, R.O.C., Department of Chemistry, National Central University, Chung-li, Taiwan, R.O.C., and National Synchrotron Radiation Research Center, Hsin-chu, 300, Taiwan, R.O.C
| | - Yen-Fu Lin
- Institute of Chemistry, Academia Sinica, Taipei,115, Taiwan, R.O.C., Department of Chemistry, National Tsing-Hua University, Hsin-chu, Taiwan, R.O.C., Department of Chemistry, National Central University, Chung-li, Taiwan, R.O.C., and National Synchrotron Radiation Research Center, Hsin-chu, 300, Taiwan, R.O.C
| | - Yu-Tai Tao
- Institute of Chemistry, Academia Sinica, Taipei,115, Taiwan, R.O.C., Department of Chemistry, National Tsing-Hua University, Hsin-chu, Taiwan, R.O.C., Department of Chemistry, National Central University, Chung-li, Taiwan, R.O.C., and National Synchrotron Radiation Research Center, Hsin-chu, 300, Taiwan, R.O.C
| | - Yao-Jane Hsu
- Institute of Chemistry, Academia Sinica, Taipei,115, Taiwan, R.O.C., Department of Chemistry, National Tsing-Hua University, Hsin-chu, Taiwan, R.O.C., Department of Chemistry, National Central University, Chung-li, Taiwan, R.O.C., and National Synchrotron Radiation Research Center, Hsin-chu, 300, Taiwan, R.O.C
| | - Der-Hsin Wei
- Institute of Chemistry, Academia Sinica, Taipei,115, Taiwan, R.O.C., Department of Chemistry, National Tsing-Hua University, Hsin-chu, Taiwan, R.O.C., Department of Chemistry, National Central University, Chung-li, Taiwan, R.O.C., and National Synchrotron Radiation Research Center, Hsin-chu, 300, Taiwan, R.O.C
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