1
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Thesberg M, Schanovsky F, Zhao Y, Karner M, Gonzalez-Medina JM, Stanojević Z, Chasin A, Rzepa G. A Physical TCAD Mobility Model of Amorphous In-Ga-Zn-O (a-IGZO) Devices with Spatially Varying Mobility Edges, Band-Tails, and Enhanced Low-Temperature Convergence. MICROMACHINES 2024; 15:829. [PMID: 39064340 PMCID: PMC11278764 DOI: 10.3390/mi15070829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2024] [Revised: 06/21/2024] [Accepted: 06/24/2024] [Indexed: 07/28/2024]
Abstract
Amorphous indium gallium zinc oxide (a-IGZO) is becoming an increasingly important technological material. Transport in this material is conceptualized as the heavy disorder of the material causing a conduction or mobility band-edge that randomly varies and undulates in space across the entire system. Thus, transport is envisioned as being dominated by percolation physics as carriers traverse this varying band-edge landscape of "hills" and "valleys". It is then something of a missed opportunity to model such a system using only a compact approach-despite this being the primary focus of the existing literature-as such a system can easily be faithfully reproduced as a true microscopic TCAD model with a real physically varying potential. Thus, in this work, we develop such a "microscopic" TCAD model of a-IGZO and detail a number of key aspects of its implementation. We then demonstrate that it can accurately reproduce experimental results and consider the issue of the addition of non-conducting band-tail states in a numerically efficient manner. Finally, two short studies of 3D effects are undertaken to illustrate the utility of the model: specifically, the cases of variation effects as a function of device size and as a function of surface roughness scattering.
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Affiliation(s)
| | | | | | - Markus Karner
- Global TCAD Solutions (GTS) GmbH, 1010 Vienna, Austria
| | | | | | | | - Gerhard Rzepa
- Global TCAD Solutions (GTS) GmbH, 1010 Vienna, Austria
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2
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Kohn JT, Gildemeister N, Grimme S, Fazzi D, Hansen A. Efficient calculation of electronic coupling integrals with the dimer projection method via a density matrix tight-binding potential. J Chem Phys 2023; 159:144106. [PMID: 37818996 DOI: 10.1063/5.0167484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 09/04/2023] [Indexed: 10/13/2023] Open
Abstract
Designing organic semiconductors for practical applications in organic solar cells, organic field-effect transistors, and organic light-emitting diodes requires understanding charge transfer mechanisms across different length and time scales. The underlying electron transfer mechanisms can be efficiently explored using semiempirical quantum mechanical (SQM) methods. The dimer projection (DIPRO) method combined with the recently introduced non-self-consistent density matrix tight-binding potential (PTB) [Grimme et al., J. Chem. Phys. 158, 124111 (2023)] is used in this study to evaluate charge transfer integrals important for understanding charge transport mechanisms. PTB, parameterized for the entire Periodic Table up to Z = 86, incorporates approximate non-local exchange, allowing for efficient and accurate calculations for large hetero-organic compounds. Benchmarking against established databases, such as Blumberger's HAB sets, or our newly introduced JAB69 set and comparing with high-level reference data from ωB97X-D4 calculations confirm that DIPRO@PTB consistently performs well among the tested SQM approaches for calculating coupling integrals. DIPRO@PTB yields reasonably accurate results at low computational cost, making it suitable for screening purposes and applications to large systems, such as metal-organic frameworks and cyanine-based molecular aggregates further discussed in this work.
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Affiliation(s)
- J T Kohn
- Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstrasse 4, 53115 Bonn, Germany
| | - N Gildemeister
- Department of Chemistry, Greinstrasse 4-6, 50939 Köln, Germany
| | - S Grimme
- Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstrasse 4, 53115 Bonn, Germany
| | - D Fazzi
- Dipartimento di Chimica "Giacomo Ciamician," Via Selmi 2, 40126 Bologna, Italy
| | - A Hansen
- Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstrasse 4, 53115 Bonn, Germany
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3
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Saladina M, Wöpke C, Göhler C, Ramirez I, Gerdes O, Liu C, Li N, Heumüller T, Brabec CJ, Walzer K, Pfeiffer M, Deibel C. Power-Law Density of States in Organic Solar Cells Revealed by the Open-Circuit Voltage Dependence of the Ideality Factor. PHYSICAL REVIEW LETTERS 2023; 130:236403. [PMID: 37354414 DOI: 10.1103/physrevlett.130.236403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 02/27/2023] [Accepted: 04/13/2023] [Indexed: 06/26/2023]
Abstract
The density of states (DOS) is fundamentally important for understanding physical processes in organic disordered semiconductors, yet hard to determine experimentally. We evaluated the DOS by considering recombination via tail states and using the temperature and open-circuit voltage (V_{oc}) dependence of the ideality factor. By performing Suns-V_{oc} measurements, we find that the energetic disorder increases deeper into the band gap, which is not expected for a Gaussian or exponential DOS. The linear dependence of the disorder on energy reveals the power-law DOS in organic solar cells.
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Affiliation(s)
- Maria Saladina
- Institut für Physik, Technische Universität Chemnitz, 09126 Chemnitz, Germany
| | - Christopher Wöpke
- Institut für Physik, Technische Universität Chemnitz, 09126 Chemnitz, Germany
| | - Clemens Göhler
- Institut für Physik, Technische Universität Chemnitz, 09126 Chemnitz, Germany
| | | | | | - Chao Liu
- Institute of Materials for Electronics and Energy Technology (i-MEET), Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
- Helmholtz Institute Erlangen-Nürnberg for Renewable Energy (HI ERN), 91058 Erlangen, Germany
| | - Ning Li
- Institute of Materials for Electronics and Energy Technology (i-MEET), Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
- Helmholtz Institute Erlangen-Nürnberg for Renewable Energy (HI ERN), 91058 Erlangen, Germany
- State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, School of Materials Science and Engineering, South China University of Technology, 510640 Guangzhou, China
| | - Thomas Heumüller
- Institute of Materials for Electronics and Energy Technology (i-MEET), Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
- Helmholtz Institute Erlangen-Nürnberg for Renewable Energy (HI ERN), 91058 Erlangen, Germany
| | - Christoph J Brabec
- Institute of Materials for Electronics and Energy Technology (i-MEET), Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
- Helmholtz Institute Erlangen-Nürnberg for Renewable Energy (HI ERN), 91058 Erlangen, Germany
| | | | | | - Carsten Deibel
- Institut für Physik, Technische Universität Chemnitz, 09126 Chemnitz, Germany
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4
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Cuadra L, Salcedo-Sanz S, Nieto-Borge JC. Organic Disordered Semiconductors as Networks Embedded in Space and Energy. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:4279. [PMID: 36500903 PMCID: PMC9741198 DOI: 10.3390/nano12234279] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 11/27/2022] [Accepted: 11/28/2022] [Indexed: 06/17/2023]
Abstract
Organic disordered semiconductors have a growing importance because of their low cost, mechanical flexibility, and multiple applications in thermoelectric devices, biosensors, and optoelectronic devices. Carrier transport consists of variable-range hopping between localized quantum states, which are disordered in both space and energy within the Gaussian disorder model. In this paper, we model an organic disordered semiconductor system as a network embedded in both space and energy so that a node represents a localized state while a link encodes the probability (or, equivalently, the Miller-Abrahams hopping rate) for carriers to hop between nodes. The associated network Laplacian matrix allows for the study of carrier dynamics using edge-centric random walks, in which links are activated by the corresponding carrier hopping rates. Our simulation work suggests that at room temperature the network exhibits a strong propensity for small-network nature, a beneficial property that in network science is related to the ease of exchanging information, particles, or energy in many different systems. However, this is not the case at low temperature. Our analysis suggests that there could be a parallelism between the well-known dependence of carrier mobility on temperature and the potential emergence of the small-world property with increasing temperature.
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Affiliation(s)
- Lucas Cuadra
- Department of Signal Processing and Communications, University of Alcalá, 28801 Alcalá de Henares, Spain
- Department of Physics and Mathematics, University of Alcalá, 28801 Alcalá de Henares, Spain
| | - Sancho Salcedo-Sanz
- Department of Signal Processing and Communications, University of Alcalá, 28801 Alcalá de Henares, Spain
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5
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Recent Progress in Conjugated Conducting and Semiconducting Polymers for Energy Devices. ENERGIES 2022. [DOI: 10.3390/en15103661] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Advanced conductors (such as conducting and semiconducting polymers) are vital building blocks for modern technologies and biocompatible devices as faster computing and smaller device sizes are demanded. Conjugated conducting and semiconducting polymers (including poly(3,4-ethylenedioxythiophene) (PEDOT), polyaniline (PANI), polythiophene (PTh), and polypyrrole (PPy)) provide the mechanical flexibility required for the next generation of energy and electronic devices. Electrical conductivity, ionic conductivity, and optoelectronic characteristics of advanced conductors are governed by their texture and constituent nanostructures. Thus, precise textural and nanostructural engineering of advanced conjugated conducting and semiconducting polymers provide an outstanding pathway to facilitate their adoption in various technological applications, including but not limited to energy storage and harvesting devices, flexible optoelectronics, bio-functional materials, and wearable electronics. This review article focuses on the basic interconnection among the nanostructure and the characteristics of conjugated conducting and semiconducting polymers. In addition, the application of conjugated conducting and semiconducting polymers in flexible energy devices and the resulting state-of-the-art device performance will be covered.
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6
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Senkovskiy BV, Nenashev AV, Alavi SK, Falke Y, Hell M, Bampoulis P, Rybkovskiy DV, Usachov DY, Fedorov AV, Chernov AI, Gebhard F, Meerholz K, Hertel D, Arita M, Okuda T, Miyamoto K, Shimada K, Fischer FR, Michely T, Baranovskii SD, Lindfors K, Szkopek T, Grüneis A. Tunneling current modulation in atomically precise graphene nanoribbon heterojunctions. Nat Commun 2021; 12:2542. [PMID: 33953174 PMCID: PMC8099867 DOI: 10.1038/s41467-021-22774-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 03/23/2021] [Indexed: 11/08/2022] Open
Abstract
Lateral heterojunctions of atomically precise graphene nanoribbons (GNRs) hold promise for applications in nanotechnology, yet their charge transport and most of the spectroscopic properties have not been investigated. Here, we synthesize a monolayer of multiple aligned heterojunctions consisting of quasi-metallic and wide-bandgap GNRs, and report characterization by scanning tunneling microscopy, angle-resolved photoemission, Raman spectroscopy, and charge transport. Comprehensive transport measurements as a function of bias and gate voltages, channel length, and temperature reveal that charge transport is dictated by tunneling through the potential barriers formed by wide-bandgap GNR segments. The current-voltage characteristics are in agreement with calculations of tunneling conductance through asymmetric barriers. We fabricate a GNR heterojunctions based sensor and demonstrate greatly improved sensitivity to adsorbates compared to graphene based sensors. This is achieved via modulation of the GNR heterojunction tunneling barriers by adsorbates.
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Affiliation(s)
| | - Alexey V Nenashev
- Rzhanov Institute of Semiconductor Physics, Novosibirsk, Russia
- Department of Physics, Novosibirsk State University, Novosibirsk, Russia
| | - Seyed K Alavi
- Department für Chemie, Universität zu Köln, Köln, Germany
- Institut für Angewandte Physik der Universität Bonn, Bonn, Germany
| | - Yannic Falke
- II. Physikalisches Institut, Universität zu Köln, Köln, Germany
| | - Martin Hell
- II. Physikalisches Institut, Universität zu Köln, Köln, Germany
| | | | | | | | - Alexander V Fedorov
- IFW Dresden, Dresden, Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie (HZB), Berlin, Germany
| | - Alexander I Chernov
- II. Physikalisches Institut, Universität zu Köln, Köln, Germany
- Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology (MIPT), Dolgoprudny, Russia
- Russian Quantum Center, Moscow, Russia
| | - Florian Gebhard
- Faculty of Physics and Material Sciences Center, Philipps-Universität, Marburg, Germany
| | - Klaus Meerholz
- Department für Chemie, Universität zu Köln, Köln, Germany
| | - Dirk Hertel
- Department für Chemie, Universität zu Köln, Köln, Germany
| | - Masashi Arita
- Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima, Japan
| | - Taichi Okuda
- Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima, Japan
| | - Koji Miyamoto
- Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima, Japan
| | - Kenya Shimada
- Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima, Japan
| | - Felix R Fischer
- Department of Chemistry, University of California at Berkeley, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Kavli Energy NanoSciences Institute at the University of California Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Thomas Michely
- II. Physikalisches Institut, Universität zu Köln, Köln, Germany
| | - Sergei D Baranovskii
- Faculty of Physics and Material Sciences Center, Philipps-Universität, Marburg, Germany
| | - Klas Lindfors
- Department für Chemie, Universität zu Köln, Köln, Germany
| | - Thomas Szkopek
- Department of Electrical and Computer Engineering, McGill University, Montreal, QC, Canada.
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7
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Simonetti O, Giraudet L. Transport models in disordered organic semiconductors and their application to the simulation of thin‐film transistors. POLYM INT 2019. [DOI: 10.1002/pi.5768] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Olivier Simonetti
- Laboratoire de Recherche en Nanosciences (LRN) ‐ EA 4682Université de Reims Champagne Ardenne Reims Cedex France
| | - Louis Giraudet
- Laboratoire de Recherche en Nanosciences (LRN) ‐ EA 4682Université de Reims Champagne Ardenne Reims Cedex France
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8
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Spoltore D, Hofacker A, Benduhn J, Ullbrich S, Nyman M, Zeika O, Schellhammer S, Fan Y, Ramirez I, Barlow S, Riede M, Marder SR, Ortmann F, Vandewal K. Hole Transport in Low-Donor-Content Organic Solar Cells. J Phys Chem Lett 2018; 9:5496-5501. [PMID: 30187758 DOI: 10.1021/acs.jpclett.8b02177] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Organic solar cells with an electron donor diluted in a fullerene matrix have a reduced density of donor-fullerene contacts, resulting in decreased free-carrier recombination and increased open-circuit voltages. However, the low donor concentration prevents the formation of percolation pathways for holes. Notwithstanding, high (>75%) external quantum efficiencies can be reached, suggesting an effective hole-transport mechanism. Here, we perform a systematic study of the hole mobilities of 18 donors, diluted at ∼6 mol % in C60, with varying frontier energy level offsets and relaxation energies. We find that hole transport between isolated donor molecules occurs by long-range tunneling through several fullerene molecules, with the hole mobilities being correlated to the relaxation energy of the donor. The transport mechanism presented in this study is of general relevance to bulk heterojunction organic solar cells where mixed phases of fullerene containing a small fraction of a donor material or vice versa are present as well.
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Affiliation(s)
- Donato Spoltore
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics , Technische Universität Dresden , 01187 Dresden , Germany
| | - Andreas Hofacker
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics , Technische Universität Dresden , 01187 Dresden , Germany
| | - Johannes Benduhn
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics , Technische Universität Dresden , 01187 Dresden , Germany
| | - Sascha Ullbrich
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics , Technische Universität Dresden , 01187 Dresden , Germany
| | - Mathias Nyman
- Physics, Faculty of Science and Engineering , Åbo Akademi University , Porthansgatan 3 , 20500 Turku , Finland
| | - Olaf Zeika
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics , Technische Universität Dresden , 01187 Dresden , Germany
| | - Sebastian Schellhammer
- Center for Advancing Electronics (cfaed) , Technische Universität Dresden , 01062 Dresden , Germany
- Institute for Materials Science and Max Bergmann Center of Biomaterials , Technische Universität Dresden , 01062 Dresden , Germany
| | - Yeli Fan
- Center for Organic Photonics and Electronics and School of Chemistry and Biochemistry , Georgia Institute of Technology , Atlanta , Georgia 30332-0400 , United States
| | - Ivan Ramirez
- Department of Physics , Oxford University , Parks Road , OX1 3PU Oxford , United Kingdom
| | - Stephen Barlow
- Center for Organic Photonics and Electronics and School of Chemistry and Biochemistry , Georgia Institute of Technology , Atlanta , Georgia 30332-0400 , United States
| | - Moritz Riede
- Department of Physics , Oxford University , Parks Road , OX1 3PU Oxford , United Kingdom
| | - Seth R Marder
- Center for Organic Photonics and Electronics and School of Chemistry and Biochemistry , Georgia Institute of Technology , Atlanta , Georgia 30332-0400 , United States
| | - Frank Ortmann
- Center for Advancing Electronics (cfaed) , Technische Universität Dresden , 01062 Dresden , Germany
| | - Koen Vandewal
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics , Technische Universität Dresden , 01187 Dresden , Germany
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9
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Brown JS, Shaheen SE. Introducing correlations into carrier transport simulations of disordered materials through seeded nucleation: impact on density of states, carrier mobility, and carrier statistics. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:135702. [PMID: 29393859 DOI: 10.1088/1361-648x/aaacb8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Disorder in organic semiconductors has made it challenging to achieve performance gains; this is a result of the many competing and often nuanced mechanisms effecting charge transport. In this article, we attempt to illuminate one of these mechanisms in the hopes of aiding experimentalists in exceeding current performance thresholds. Using a heuristic exponential function, energetic correlation has been added to the Gaussian disorder model (GDM). The new model is grounded in the concept that energetic correlations can arise in materials without strong dipoles or dopants, but may be a result of an incomplete crystal formation process. The proposed correlation has been used to explain the exponential tail states often observed in these materials; it is also better able to capture the carrier mobility field dependence, commonly known as the Poole-Frenkel dependence, when compared to the GDM. Investigation of simulated current transients shows that the exponential tail states do not necessitate Montroll and Scher fits. Montroll and Scher fits occur in the form of two distinct power law curves that share a common constant in their exponent; they are clearly observed as linear lines when the current transient is plotted using a log-log scale. Typically, these fits have been found appropriate for describing amorphous silicon and other disordered materials which display exponential tail states. Furthermore, we observe the proposed correlation function leads to domains of energetically similar sites separated by boundaries where the site energies exhibit stochastic deviation. These boundary sites are found to be the source of the extended exponential tail states, and are responsible for high charge visitation frequency, which may be associated with the molecular turnover number and ultimately the material stability.
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Affiliation(s)
- J S Brown
- Department of Electrical Computer and Energy Engineering, University of Colorado Boulder, 425 UCB, Boulder, CO 80309, United States of America. Renewable and Sustainable Energy Institute, University of Colorado Boulder, 4001 Discovery Dr, Boulder, CO 80303, United States of America
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10
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Abstract
Organic (opto)electronic materials have received considerable attention due to their applications in thin-film-transistors, light-emitting diodes, solar cells, sensors, photorefractive devices, and many others. The technological promises include low cost of these materials and the possibility of their room-temperature deposition from solution on large-area and/or flexible substrates. The article reviews the current understanding of the physical mechanisms that determine the (opto)electronic properties of high-performance organic materials. The focus of the review is on photoinduced processes and on electronic properties important for optoelectronic applications relying on charge carrier photogeneration. Additionally, it highlights the capabilities of various experimental techniques for characterization of these materials, summarizes top-of-the-line device performance, and outlines recent trends in the further development of the field. The properties of materials based both on small molecules and on conjugated polymers are considered, and their applications in organic solar cells, photodetectors, and photorefractive devices are discussed.
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Affiliation(s)
- Oksana Ostroverkhova
- Department of Physics, Oregon State University , Corvallis, Oregon 97331, United States
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11
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Novikov SV. Far tails of the density of states in amorphous organic semiconductors. J Chem Phys 2015; 143:164510. [DOI: 10.1063/1.4934648] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- S. V. Novikov
- A. N. Frumkin Institute of Physical Chemistry and Electrochemistry, Leninsky Prospect 31, 119071 Moscow, Russia and National Research University Higher School of Economics, Myasnitskaya Ulitsa 20, Moscow 101000, Russia
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