1
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Zojer E. Electrostatically Designing Materials and Interfaces. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2406178. [PMID: 39194368 DOI: 10.1002/adma.202406178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 07/08/2024] [Indexed: 08/29/2024]
Abstract
Collective electrostatic effects arise from the superposition of electrostatic potentials of periodically arranged (di)polar entities and are known to crucially impact the electronic structures of hybrid interfaces. Here, it is discussed, how they can be used outside the beaten paths of materials design for realizing systems with advanced and sometimes unprecedented properties. The versatility of the approach is demonstrated by applying electrostatic design not only to metal-organic interfaces and adsorbed (complex) monolayers, but also to inter-layer interfaces in van der Waals heterostructures, to polar metal-organic frameworks (MOFs), and to the cylindrical pores of covalent organic frameworks (COFs). The presented design ideas are straightforward to simulate and especially for metal-organic interfaces also their experimental implementation has been amply demonstrated. For van der Waals heterostructures, the needed building blocks are available, while the required assembly approaches are just being developed. Conversely, for MOFs the necessary growth techniques exist, but more work on advanced linker molecules is required. Finally, COF structures exist that contain pores decorated with polar groups, but the electrostatic impact of these groups has been largely ignored so far. All this suggest that the dawn of the age of electrostatic design is currently experienced with potential breakthroughs lying ahead.
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Affiliation(s)
- Egbert Zojer
- Institute of Solid State Physics, NAWI Graz, Petersgasse 16, Graz, A-8010, Austria
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2
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Pranav M, Shukla A, Moser D, Rumeney J, Liu W, Wang R, Sun B, Smeets S, Tokmoldin N, Cao Y, He G, Beitz T, Jaiser F, Hultzsch T, Shoaee S, Maes W, Lüer L, Brabec C, Vandewal K, Andrienko D, Ludwigs S, Neher D. On the critical competition between singlet exciton decay and free charge generation in non-fullerene based organic solar cells with low energetic offsets. ENERGY & ENVIRONMENTAL SCIENCE 2024; 17:6676-6697. [PMID: 39157178 PMCID: PMC11323475 DOI: 10.1039/d4ee01409j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 07/16/2024] [Indexed: 08/20/2024]
Abstract
Reducing voltage losses while maintaining high photocurrents is the holy grail of current research on non-fullerene acceptor (NFA) based organic solar cell. Recent focus lies in understanding the various fundamental mechanisms in organic blends with minimal energy offsets - particularly the relationship between ionization energy offset (ΔIE) and free charge generation. Here, we quantitatively probe this relationship in multiple NFA-based blends by mixing Y-series NFAs with PM6 of different molecular weights, covering a broad power conversion efficiency (PCE) range: from 15% down to 1%. Spectroelectrochemistry reveals that a ΔIE of more than 0.3 eV is necessary for efficient photocurrent generation. Bias-dependent time-delayed collection experiments reveal a very pronounced field-dependence of free charge generation for small ΔIE blends, which is mirrored by a strong and simultaneous field-dependence of the quantified photoluminescence from the NFA local singlet exciton (LE). We find that the decay of singlet excitons is the primary competition to free charge generation in low-offset NFA-based organic solar cells, with neither noticeable losses from charge-transfer (CT) decay nor evidence for LE-CT hybridization. In agreement with this conclusion, transient absorption spectroscopy consistently reveals that a smaller ΔIE slows the NFA exciton dissociation into free charges, albeit restorable by an electric field. Our experimental data align with Marcus theory calculations, supported by density functional theory simulations, for zero-field free charge generation and exciton decay efficiencies. We conclude that efficient photocurrent generation generally requires that the CT state is located below the LE, but that this restriction is lifted in systems with a small reorganization energy for charge transfer.
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Affiliation(s)
- Manasi Pranav
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht Straße 24/25 14476 Potsdam Germany
| | - Atul Shukla
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht Straße 24/25 14476 Potsdam Germany
| | - David Moser
- IPOC - Functional Polymers, Institute of Polymer Chemistry, University of Stuttgart, Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Julia Rumeney
- IPOC - Functional Polymers, Institute of Polymer Chemistry, University of Stuttgart, Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Wenlan Liu
- Max Planck Institute for Polymer Research, Ackermannweg 10 55128 Mainz Germany
| | - Rong Wang
- Institute of Materials for Electronics and Energy Technology (i-MEET), Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstrasse 7 Erlangen 91058 Germany
| | - Bowen Sun
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht Straße 24/25 14476 Potsdam Germany
| | - Sander Smeets
- UHasselt-Hasselt University, Institute for Materials Research, (IMO-IMOMEC), Agoralaan 1 3590 Diepenbeek Belgium
- IMOMEC Division, IMEC, Wetenschapspark 1 3590 Diepenbeek Belgium
| | - Nurlan Tokmoldin
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht Straße 24/25 14476 Potsdam Germany
- Heterostructure Semiconductor Physics, Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e. V, Hausvogteiplatz 5-7 10117 Berlin Germany
| | - Yonglin Cao
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht Straße 24/25 14476 Potsdam Germany
| | - Guorui He
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht Straße 24/25 14476 Potsdam Germany
| | - Thorben Beitz
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht Straße 24/25 14476 Potsdam Germany
| | - Frank Jaiser
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht Straße 24/25 14476 Potsdam Germany
| | - Thomas Hultzsch
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht Straße 24/25 14476 Potsdam Germany
| | - Safa Shoaee
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht Straße 24/25 14476 Potsdam Germany
- Heterostructure Semiconductor Physics, Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e. V, Hausvogteiplatz 5-7 10117 Berlin Germany
| | - Wouter Maes
- UHasselt-Hasselt University, Institute for Materials Research, (IMO-IMOMEC), Agoralaan 1 3590 Diepenbeek Belgium
- IMOMEC Division, IMEC, Wetenschapspark 1 3590 Diepenbeek Belgium
| | - Larry Lüer
- Institute of Materials for Electronics and Energy Technology (i-MEET), Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstrasse 7 Erlangen 91058 Germany
| | - Christoph Brabec
- Institute of Materials for Electronics and Energy Technology (i-MEET), Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstrasse 7 Erlangen 91058 Germany
- Helmholtz-Institut Erlangen-Nürnberg for Renewable Energies (HIERN), Forschungszentrum Jülich, Immerwahrstraße 2 91058 Erlangen Germany
| | - Koen Vandewal
- UHasselt-Hasselt University, Institute for Materials Research, (IMO-IMOMEC), Agoralaan 1 3590 Diepenbeek Belgium
- IMOMEC Division, IMEC, Wetenschapspark 1 3590 Diepenbeek Belgium
| | - Denis Andrienko
- Max Planck Institute for Polymer Research, Ackermannweg 10 55128 Mainz Germany
| | - Sabine Ludwigs
- IPOC - Functional Polymers, Institute of Polymer Chemistry, University of Stuttgart, Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Dieter Neher
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht Straße 24/25 14476 Potsdam Germany
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3
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Langa F, de la Cruz P, Sharma GD. Organic Solar Cells Based on Non-Fullerene Low Molecular Weight Organic Semiconductor Molecules. CHEMSUSCHEM 2024:e202400361. [PMID: 39240557 DOI: 10.1002/cssc.202400361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 06/28/2024] [Indexed: 09/07/2024]
Abstract
The development of narrow bandgap A-D-A- and ADA'DA-type non-fullerene small molecule acceptors (NFSMAs) along with small molecule donors (SMDs) have led to significant progress in all-small molecule organic solar cells. Remarkable power conversion efficiencies, nearing the range of 17-18 %, have been realized. These efficiency values are on par with those achieved in OSCs based on polymeric donors. The commercial application of organic photovoltaic technology requires the design of more efficient organic conjugated small molecule donors and acceptors. In recent years the precise tuning of optoelectronic properties in small molecule donors and acceptors has attracted considerable attention and has contributed greatly to the advancement of all-SM-OSCs. Several reviews have been published in this field, but the focus of this review concerns the advances in research on OSCs using SMDs and NFSMAs from 2018 to the present. The review covers the progress made in binary and ternary OSCs, the effects of solid additives on the performance of all-SM-OSCs, and the recently developed layer-by-layer deposition method for these OSCs. Finally, we present our perspectives and a concise outlook on further advances in all-SM-OSCs for their commercial application.
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Affiliation(s)
- Fernando Langa
- Universidad de Castilla-La Mancha, Instituto de Nanociencia, Nanotecnología y Materiales Moleculares (INAMOL), Campus de la Fábrica de Armas, 45071, Toledo, Spain
| | - Pilar de la Cruz
- Universidad de Castilla-La Mancha, Instituto de Nanociencia, Nanotecnología y Materiales Moleculares (INAMOL), Campus de la Fábrica de Armas, 45071, Toledo, Spain
| | - Ganesh D Sharma
- Department of Physics, The LNM Institute of Information Technology, Jamdoli, Jaipur (Rai), 302031, India
- Department of Electronics and Communication Engineering, The LNM Institute of Information Technology, Jamdoli, Jaipur (Rai), 302031, India
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Shoaee S, Luong HM, Song J, Zou Y, Nguyen TQ, Neher D. What We have Learnt from PM6:Y6. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2302005. [PMID: 37623325 DOI: 10.1002/adma.202302005] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 07/10/2023] [Indexed: 08/26/2023]
Abstract
Over the past three years, remarkable advancements in organic solar cells (OSCs) have emerged, propelled by the introduction of Y6-an innovative A-DA'D-A type small molecule non-fullerene acceptor (NFA). This review provides a critical discussion of the current knowledge about the structural and physical properties of the PM6:Y6 material combination in relation to its photovoltaic performance. The design principles of PM6 and Y6 are discussed, covering charge transfer, transport, and recombination mechanisms. Then, the authors delve into blend morphology and degradation mechanisms before considering commercialization. The current state of the art is presented, while also discussing unresolved contentious issues, such as the blend energetics, the pathways of free charge generation, and the role of triplet states in recombination. As such, this review aims to provide a comprehensive understanding of the PM6:Y6 material combination and its potential for further development in the field of organic solar cells. By addressing both the successes and challenges associated with this system, this review contributes to the ongoing research efforts toward achieving more efficient and stable organic solar cells.
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Affiliation(s)
- Safa Shoaee
- Optoelectronics of Disordered Semiconductors, Institute of Physics and Astronomy, University of Potsdam, D-14476, Potsdam-Golm, Germany
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., 10117, Berlin, Germany
| | - Hoang M Luong
- Centre for Polymers and Organic Solids, University of California, Santa Barbara, CA, 93106, USA
| | - Jiage Song
- College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, P. R. China
| | - Yingping Zou
- College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, P. R. China
| | - Thuc-Quyen Nguyen
- Centre for Polymers and Organic Solids, University of California, Santa Barbara, CA, 93106, USA
| | - Dieter Neher
- Soft Matter Physics and Optoelectronics, Institute of Physics and Astronomy, University of Potsdam, D-14476, Potsdam-Golm, Germany
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5
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Hume PA, Price MB, Hodgkiss JM. New Avenues for Organic Solar Cells Using Intrinsically Charge-Generating Materials. JACS AU 2024; 4:1295-1302. [PMID: 38665646 PMCID: PMC11040696 DOI: 10.1021/jacsau.4c00046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 03/03/2024] [Accepted: 03/04/2024] [Indexed: 04/28/2024]
Abstract
The molecular electron acceptor material Y6 has been a key part of the most recent surge in organic solar cell sunlight-to-electricity power conversion efficiency, which is now approaching 20%. Numerous studies have sought to understand the fundamental photophysical reasons for the exceptional performance of Y6 and its growing family of structural derivatives. Though significant uncertainty about several details remains, many have concluded that initially photogenerated excited states rapidly convert into electron-hole charge pairs in the neat material. These charge pairs are characterized by location of the electron and hole on different Y6 molecules, in contrast to the Frenkel excitons that dominate the behavior of most organic semiconductor materials. Here, we summarize the current state of knowledge regarding Y6 photophysics and the key observations that have led to it. We then link this understanding to other advances, such as the role of quadrupolar fields in donor-acceptor blends, and the importance of molecular interactions and organization in providing the structural basis for Y6's properties. Finally, we turn our attention to ways of making use of the new photophysics of Y6, and suggest molecular doping, crystal structure tuning, and electric field engineering as promising avenues for future exploration.
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Affiliation(s)
- Paul A. Hume
- School
of Chemical and Physical Sciences, Victoria
University of Wellington, Wellington, 6012, New Zealand
- MacDiarmid
Institute for Advanced Materials and Nanotechnology, Wellington, 6012, New Zealand
| | - Michael B. Price
- School
of Chemistry, University of Bristol, Bristol, BS8 1TS, United Kingdom
| | - Justin M. Hodgkiss
- School
of Chemical and Physical Sciences, Victoria
University of Wellington, Wellington, 6012, New Zealand
- MacDiarmid
Institute for Advanced Materials and Nanotechnology, Wellington, 6012, New Zealand
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6
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Sharma A, Gasparini N, Markina A, Karuthedath S, Gorenflot J, Xu H, Han J, Balawi A, Liu W, Bryant D, Bertrandie J, Troughton J, Paleti SHK, Bristow H, Laquai F, Andrienko D, Baran D. Semitransparent Organic Photovoltaics Utilizing Intrinsic Charge Generation in Non-Fullerene Acceptors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2305367. [PMID: 38100279 DOI: 10.1002/adma.202305367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 10/11/2023] [Indexed: 12/17/2023]
Abstract
In organic semiconductors, a donor/acceptor heterojunction is typically required for efficient dissociation of excitons. Using transient absorption spectroscopy to study the dynamics of excited states in non-fullerene acceptors (NFAs), it is shown that NFAs can generate charges without a donor/acceptor interface. This is due to the fact that dielectric solvation provides a driving force sufficient to dissociate the excited state and form the charge-transfer (CT) state. The CT state is further dissociated into free charges at interfaces between polycrystalline regions in neat NFAs. For IEICO-4F, incorporating just 9 wt% donor polymer PTB7-Th in neat films greatly boosts charge generation, enhancing efficient exciton separation into free charges. This property is utilized to fabricate donor-dilute organic photovoltaics (OPV) delivering a power conversion efficiency of 8.3% in the case of opaque devices with a metal top-electrode and an active layer average visible transmittance (AVT) of 75%. It is shown that the intrinsic charge generation in low-bandgap NFAs contributes to the overall photocurrent generation. IEICO-4F-based OPVs with limited PTB7-Th content have high thermal resilience demonstrating little drop in performance over 700 h. PTB7-Th:IEICO-4F semitransparent OPVs are leveraged to fabricate an 8-series connected semitransparent module, demonstrating light-utilization efficiency of 2.2% alongside an AVT of 63%.
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Affiliation(s)
- Anirudh Sharma
- Materials Science and Engineering Program, Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Nicola Gasparini
- Materials Science and Engineering Program, Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Anastasia Markina
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Safakath Karuthedath
- Materials Science and Engineering Program, Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
- Institute of Materials Research, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China
| | - Julien Gorenflot
- Materials Science and Engineering Program, Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Han Xu
- Materials Science and Engineering Program, Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Jianhua Han
- Materials Science and Engineering Program, Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Ahmed Balawi
- Materials Science and Engineering Program, Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Wenlan Liu
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Daniel Bryant
- Materials Science and Engineering Program, Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Jules Bertrandie
- Materials Science and Engineering Program, Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Joel Troughton
- Materials Science and Engineering Program, Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Sri Harish Kumar Paleti
- Materials Science and Engineering Program, Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Helen Bristow
- Materials Science and Engineering Program, Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Frederic Laquai
- Materials Science and Engineering Program, Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Denis Andrienko
- Materials Science and Engineering Program, Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Derya Baran
- Materials Science and Engineering Program, Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
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7
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Duan T, Feng W, Li Y, Li Z, Zhang Z, Liang H, Chen H, Zhong C, Jeong S, Yang C, Chen S, Lu S, Rakitin OA, Li C, Wan X, Kan B, Chen Y. Electronic Configuration Tuning of Centrally Extended Non-Fullerene Acceptors Enabling Organic Solar Cells with Efficiency Approaching 19 . Angew Chem Int Ed Engl 2023; 62:e202308832. [PMID: 37626468 DOI: 10.1002/anie.202308832] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 08/14/2023] [Accepted: 08/25/2023] [Indexed: 08/27/2023]
Abstract
In the molecular optimizations of non-fullerene acceptors (NFAs), extending the central core can tune the energy levels, reduce nonradiative energy loss, enhance the intramolecular (donor-acceptor and acceptor-acceptor) packing, facilitate the charge transport, and improve device performance. In this study, a new strategy was employed to synthesize acceptors featuring conjugation-extended electron-deficient cores. Among these, the acceptor CH-BBQ, embedded with benzobisthiadiazole, exhibited an optimal fibrillar network morphology, enhanced crystallinity, and improved charge generation/transport in blend films, leading to a power conversion efficiency of 18.94 % for CH-BBQ-based ternary organic solar cells (OSCs; 18.19 % for binary OSCs) owing to its delicate structure design and electronic configuration tuning. Both experimental and theoretical approaches were used to systematically investigate the influence of the central electron-deficient core on the properties of the acceptor and device performance. The electron-deficient core modulation paves a new pathway in the molecular engineering of NFAs, propelling relevant research forward.
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Affiliation(s)
- Tainan Duan
- State Key Laboratory and Institute of Elemento-Organic Chemistry, The Centre of Nanoscale Science and Technology and Key Laboratory of Functional Polymer Materials, Renewable Energy Conversion and Storage Center (RECAST), College of Chemistry, Nankai University, Tianjin, 300071, China
- Chongqing Institute of Green and Intelligent Technology, Chongqing School, University of Chinese Academy of Sciences (UCAS Chongqing), Chinese Academy of Sciences, Chongqing, 400714, China
| | - Wanying Feng
- State Key Laboratory and Institute of Elemento-Organic Chemistry, The Centre of Nanoscale Science and Technology and Key Laboratory of Functional Polymer Materials, Renewable Energy Conversion and Storage Center (RECAST), College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Yulu Li
- Chongqing Institute of Green and Intelligent Technology, Chongqing School, University of Chinese Academy of Sciences (UCAS Chongqing), Chinese Academy of Sciences, Chongqing, 400714, China
| | - Zhixiang Li
- State Key Laboratory and Institute of Elemento-Organic Chemistry, The Centre of Nanoscale Science and Technology and Key Laboratory of Functional Polymer Materials, Renewable Energy Conversion and Storage Center (RECAST), College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Zhe Zhang
- State Key Laboratory and Institute of Elemento-Organic Chemistry, The Centre of Nanoscale Science and Technology and Key Laboratory of Functional Polymer Materials, Renewable Energy Conversion and Storage Center (RECAST), College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Huazhe Liang
- State Key Laboratory and Institute of Elemento-Organic Chemistry, The Centre of Nanoscale Science and Technology and Key Laboratory of Functional Polymer Materials, Renewable Energy Conversion and Storage Center (RECAST), College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Hongbin Chen
- State Key Laboratory and Institute of Elemento-Organic Chemistry, The Centre of Nanoscale Science and Technology and Key Laboratory of Functional Polymer Materials, Renewable Energy Conversion and Storage Center (RECAST), College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Cheng Zhong
- Hubei Key Laboratory on Organic and Polymeric Opto-electronic Materials, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
| | - Seonghun Jeong
- Department of Energy Engineering, School of Energy and Chemical Engineering, Perovtronics Research Center, Low Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Changduk Yang
- Department of Energy Engineering, School of Energy and Chemical Engineering, Perovtronics Research Center, Low Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Shanshan Chen
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems, CQU-NUS Renewable Energy Materials & Devices Joint Laboratory, School of Energy & Power Engineering, Chongqing University, Chongqing, 400044, China
| | - Shirong Lu
- Chongqing Institute of Green and Intelligent Technology, Chongqing School, University of Chinese Academy of Sciences (UCAS Chongqing), Chinese Academy of Sciences, Chongqing, 400714, China
| | - Oleg A Rakitin
- N. D. Zelinsky Institute of Organic Chemistry Russian Academy of Sciences, 47 Leninsky Prospekt, 119991, Moscow, Russia
| | - Chenxi Li
- State Key Laboratory and Institute of Elemento-Organic Chemistry, The Centre of Nanoscale Science and Technology and Key Laboratory of Functional Polymer Materials, Renewable Energy Conversion and Storage Center (RECAST), College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Xiangjian Wan
- State Key Laboratory and Institute of Elemento-Organic Chemistry, The Centre of Nanoscale Science and Technology and Key Laboratory of Functional Polymer Materials, Renewable Energy Conversion and Storage Center (RECAST), College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Bin Kan
- School of Materials Science and Engineering, National Institute for Advanced Materials, Nankai University, Tianjin, 300350, China
| | - Yongsheng Chen
- State Key Laboratory and Institute of Elemento-Organic Chemistry, The Centre of Nanoscale Science and Technology and Key Laboratory of Functional Polymer Materials, Renewable Energy Conversion and Storage Center (RECAST), College of Chemistry, Nankai University, Tianjin, 300071, China
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8
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Wu Y, Li Y, van der Zee B, Liu W, Markina A, Fan H, Yang H, Cui C, Li Y, Blom PWM, Andrienko D, Wetzelaer GJAH. Reduced bimolecular charge recombination in efficient organic solar cells comprising non-fullerene acceptors. Sci Rep 2023; 13:4717. [PMID: 36949087 PMCID: PMC10033508 DOI: 10.1038/s41598-023-31929-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 03/20/2023] [Indexed: 03/24/2023] Open
Abstract
Bimolecular charge recombination is one of the most important loss processes in organic solar cells. However, the bimolecular recombination rate in solar cells based on novel non-fullerene acceptors is mostly unclear. Moreover, the origin of the reduced-Langevin recombination rate in bulk heterojunction solar cells in general is still poorly understood. Here, we investigate the bimolecular recombination rate and charge transport in a series of high-performance organic solar cells based on non-fullerene acceptors. From steady-state dark injection measurements and drift-diffusion simulations of the current-voltage characteristics under illumination, Langevin reduction factors of up to over two orders of magnitude are observed. The reduced recombination is essential for the high fill factors of these solar cells. The Langevin reduction factors are observed to correlate with the quadrupole moment of the acceptors, which is responsible for band bending at the donor-acceptor interface, forming a barrier for charge recombination. Overall these results therefore show that suppressed bimolecular recombination is essential for the performance of organic solar cells and provide design rules for novel materials.
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Affiliation(s)
- Yue Wu
- Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Yungui Li
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Bas van der Zee
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Wenlan Liu
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Anastasia Markina
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Hongyu Fan
- Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China
| | - Hang Yang
- Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China
| | - Chaohua Cui
- Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China.
| | - Yongfang Li
- Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China
| | - Paul W M Blom
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Denis Andrienko
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
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9
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Wang Y, Price MB, Bobba RS, Lu H, Xue J, Wang Y, Li M, Ilina A, Hume PA, Jia B, Li T, Zhang Y, Davis NJLK, Tang Z, Ma W, Qiao Q, Hodgkiss JM, Zhan X. Quasi-Homojunction Organic Nonfullerene Photovoltaics Featuring Fundamentals Distinct from Bulk Heterojunctions. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2206717. [PMID: 36189867 DOI: 10.1002/adma.202206717] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 09/21/2022] [Indexed: 06/16/2023]
Abstract
In contrast to classical bulk heterojunction (BHJ) in organic solar cells (OSCs), the quasi-homojunction (QHJ) with extremely low donor content (≤10 wt.%) is unusual and generally yields much lower device efficiency. Here, representative polymer donors and nonfullerene acceptors are selected to fabricate QHJ OSCs, and a complete picture for the operation mechanisms of high-efficiency QHJ devices is illustrated. PTB7-Th:Y6 QHJ devices at donor:acceptor (D:A) ratios of 1:8 or 1:20 can achieve 95% or 64% of the efficiency obtained from its BHJ counterpart at the optimal D:A ratio of 1:1.2, respectively, whereas QHJ devices with other donors or acceptors suffer from rapid roll-off of efficiency when the donors are diluted. Through device physics and photophysics analyses, it is observed that a large portion of free charges can be intrinsically generated in the neat Y6 domains rather than at the D/A interface. Y6 also serves as an ambipolar transport channel, so that hole transport as also mainly through Y6 phase. The key role of PTB7-Th is primarily to reduce charge recombination, likely assisted by enhancing quadrupolar fields within Y6 itself, rather than the previously thought principal roles of light absorption, exciton splitting, and hole transport.
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Affiliation(s)
- Yifan Wang
- College of Materials Science and Engineering, Qingdao University, Qingdao, 266071, P. R. China
- Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, School of Materials Science and Engineering, Peking University, Beijing, 100871, P. R. China
| | - Michael B Price
- MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, 6010, New Zealand
| | - Raja Sekhar Bobba
- Department of Mechanical and Aerospace Engineering, Syracuse University, Syracuse, NY, 13244, USA
| | - Heng Lu
- Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, School of Materials Science and Engineering, Peking University, Beijing, 100871, P. R. China
| | - Jingwei Xue
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China
| | - Yilin Wang
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China
| | - Mengyang Li
- Center for Advanced Low-Dimension Materials, State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai, 201620, P. R. China
| | - Aleksandra Ilina
- MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, 6010, New Zealand
| | - Paul A Hume
- MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, 6010, New Zealand
| | - Boyu Jia
- Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, School of Materials Science and Engineering, Peking University, Beijing, 100871, P. R. China
| | - Tengfei Li
- Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, School of Materials Science and Engineering, Peking University, Beijing, 100871, P. R. China
| | - Yuchen Zhang
- Department of Mechanical and Aerospace Engineering, Syracuse University, Syracuse, NY, 13244, USA
| | - Nathaniel J L K Davis
- MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, 6010, New Zealand
| | - Zheng Tang
- Center for Advanced Low-Dimension Materials, State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai, 201620, P. R. China
| | - Wei Ma
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China
| | - Quinn Qiao
- Department of Mechanical and Aerospace Engineering, Syracuse University, Syracuse, NY, 13244, USA
| | - Justin M Hodgkiss
- MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, 6010, New Zealand
| | - Xiaowei Zhan
- Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, School of Materials Science and Engineering, Peking University, Beijing, 100871, P. R. China
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10
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Abd-Rahman SA, Yamaguchi T, Kera S, Yoshida H. Sample-shape dependent energy levels in organic semiconductors. PHYSICAL REVIEW B 2022; 106:075303. [DOI: 10.1103/physrevb.106.075303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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11
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Price MB, Hume PA, Ilina A, Wagner I, Tamming RR, Thorn KE, Jiao W, Goldingay A, Conaghan PJ, Lakhwani G, Davis NJLK, Wang Y, Xue P, Lu H, Chen K, Zhan X, Hodgkiss JM. Free charge photogeneration in a single component high photovoltaic efficiency organic semiconductor. Nat Commun 2022; 13:2827. [PMID: 35595764 PMCID: PMC9122989 DOI: 10.1038/s41467-022-30127-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 04/15/2022] [Indexed: 11/09/2022] Open
Abstract
Organic photovoltaics (OPVs) promise cheap and flexible solar energy. Whereas light generates free charges in silicon photovoltaics, excitons are normally formed in organic semiconductors due to their low dielectric constants, and require molecular heterojunctions to split into charges. Recent record efficiency OPVs utilise the small molecule, Y6, and its analogues, which – unlike previous organic semiconductors – have low band-gaps and high dielectric constants. We show that, in Y6 films, these factors lead to intrinsic free charge generation without a heterojunction. Intensity-dependent spectroscopy reveals that 60–90% of excitons form free charges at AM1.5 light intensity. Bimolecular recombination, and hole traps constrain single component Y6 photovoltaics to low efficiencies, but recombination is reduced by small quantities of donor. Quantum-chemical calculations reveal strong coupling between exciton and CT states, and an intermolecular polarisation pattern that drives exciton dissociation. Our results challenge how current OPVs operate, and renew the possibility of efficient single-component OPVs. When light hits organic semiconductors, bound charge pairs, called excitons, are usually produced. Here, the authors show that in the best performing organic solar material to date, free charges, rather than excitons, are directly created by light.
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Affiliation(s)
- Michael B Price
- School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand. .,MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, New Zealand.
| | - Paul A Hume
- School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand. .,MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, New Zealand.
| | - Aleksandra Ilina
- School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand.,MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, New Zealand
| | - Isabella Wagner
- School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand.,MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, New Zealand
| | - Ronnie R Tamming
- School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand.,MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, New Zealand.,Wellington UniVentures, Victoria University of Wellington, Wellington, New Zealand.,Robinson Research Institute, Faculty of Engineering, Victoria University of Wellington, Wellington, New Zealand.,The Dodd-Walls Centre for Photonic and Quantum Technologies, Dunedin, New Zealand
| | - Karen E Thorn
- School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand.,MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, New Zealand
| | - Wanting Jiao
- Ferrier Research Institute, Victoria University of Wellington, Wellington, New Zealand
| | - Alison Goldingay
- ARC Centre of Excellence in Exciton Science, School of Chemistry, University of Sydney, Sydney, NSW, Australia
| | - Patrick J Conaghan
- ARC Centre of Excellence in Exciton Science, School of Chemistry, University of Sydney, Sydney, NSW, Australia
| | - Girish Lakhwani
- ARC Centre of Excellence in Exciton Science, School of Chemistry, University of Sydney, Sydney, NSW, Australia
| | - Nathaniel J L K Davis
- School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand.,MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, New Zealand
| | - Yifan Wang
- School of Materials Science and Engineering, Peking University, Beijing, China.,College of Materials Science and Engineering, Qingdao University, Qingdao, China
| | - Peiyao Xue
- School of Materials Science and Engineering, Peking University, Beijing, China
| | - Heng Lu
- School of Materials Science and Engineering, Peking University, Beijing, China
| | - Kai Chen
- School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand.,MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, New Zealand.,Wellington UniVentures, Victoria University of Wellington, Wellington, New Zealand.,Robinson Research Institute, Faculty of Engineering, Victoria University of Wellington, Wellington, New Zealand.,The Dodd-Walls Centre for Photonic and Quantum Technologies, Dunedin, New Zealand
| | - Xiaowei Zhan
- School of Materials Science and Engineering, Peking University, Beijing, China
| | - Justin M Hodgkiss
- School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand. .,MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, New Zealand.
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12
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Chaney TP, Levin AJ, Schneider SA, Toney MF. Scattering techniques for mixed donor-acceptor characterization in organic photovoltaics. MATERIALS HORIZONS 2022; 9:43-60. [PMID: 34797358 DOI: 10.1039/d1mh01219c] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Precise control of the complex morphology of organic photovoltaic bulk heterojunction (BHJ) active layers remains an important yet challenging approach for improving power conversion efficiency. Of particular interest are the interfacial regions between electron donor and acceptor molecules where charge separation and charge recombination occur. Often, these interfaces feature a molecularly mixed donor-acceptor phase. This mixed phase has been extensively studied in polymer:fullerene systems but is poorly understood in state-of-the-art polymer:non-fullerene acceptor blends. Accurate, quantitative characterization of this mixed phase is critical to unraveling its importance for charge separation and recombination processes within the BHJ. Here, we detail X-ray and neutron scattering characterization techniques and analysis methods to quantify the mixed phase within BHJ active layers. We then review the existing literature where these techniques have been successfully used on several different material systems and correlated to device performance. Finally, future challenges for characterizing non-fullerene acceptor systems are addressed, and emerging strategies are discussed.
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Affiliation(s)
- Thomas P Chaney
- Materials Science and Engineering, University of Colorado, Boulder, CO 80309, USA.
| | - Andrew J Levin
- Materials Science and Engineering, University of Colorado, Boulder, CO 80309, USA.
| | - Sebastian A Schneider
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Michael F Toney
- Materials Science and Engineering, University of Colorado, Boulder, CO 80309, USA.
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80309, USA
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13
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Schmidt AM, Calvete MJF. Phthalocyanines: An Old Dog Can Still Have New (Photo)Tricks! Molecules 2021; 26:2823. [PMID: 34068708 PMCID: PMC8126243 DOI: 10.3390/molecules26092823] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 04/23/2021] [Accepted: 05/06/2021] [Indexed: 12/13/2022] Open
Abstract
Phthalocyanines have enjoyed throughout the years the benefits of being exquisite compounds with many favorable properties arising from the straightforward and diverse possibilities of their structural modulation. Last decades appreciated a steady growth in applications for phthalocyanines, particularly those dependent on their great photophysical properties, now used in several cutting-edge technologies, particularly in photonic applications. Judging by the vivid reports currently provided by many researchers around the world, the spotlight remains assured. This review deals with the use of phthalocyanine molecules in innovative materials in photo-applications. Beyond a comprehensive view on the recent discoveries, a critical review of the most acclaimed/considered reports is the driving force, providing a brief and direct insight on the latest milestones in phthalocyanine photonic-based science.
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Affiliation(s)
- Andrea M. Schmidt
- LifeEstetika, Laser Solutions, Universitätstadt Tübingen, Maria-von-Linden Strasse, 72076 Tübingen, Germany;
| | - Mário J. F. Calvete
- University of Coimbra, CQC, Department of Chemistry, Rua Larga, 3004-535 Coimbra, Portugal
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14
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Affiliation(s)
- Justin M Hodgkiss
- School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand.
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, New Zealand.
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15
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Karuthedath S, Gorenflot J, Firdaus Y, Chaturvedi N, De Castro CSP, Harrison GT, Khan JI, Markina A, Balawi AH, Peña TAD, Liu W, Liang RZ, Sharma A, Paleti SHK, Zhang W, Lin Y, Alarousu E, Lopatin S, Anjum DH, Beaujuge PM, De Wolf S, McCulloch I, Anthopoulos TD, Baran D, Andrienko D, Laquai F. Intrinsic efficiency limits in low-bandgap non-fullerene acceptor organic solar cells. NATURE MATERIALS 2021; 20:378-384. [PMID: 33106652 DOI: 10.1038/s41563-020-00835-x] [Citation(s) in RCA: 109] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Accepted: 09/17/2020] [Indexed: 05/20/2023]
Abstract
In bulk heterojunction (BHJ) organic solar cells (OSCs) both the electron affinity (EA) and ionization energy (IE) offsets at the donor-acceptor interface should equally control exciton dissociation. Here, we demonstrate that in low-bandgap non-fullerene acceptor (NFA) BHJs ultrafast donor-to-acceptor energy transfer precedes hole transfer from the acceptor to the donor and thus renders the EA offset virtually unimportant. Moreover, sizeable bulk IE offsets of about 0.5 eV are needed for efficient charge transfer and high internal quantum efficiencies, since energy level bending at the donor-NFA interface caused by the acceptors' quadrupole moments prevents efficient exciton-to-charge-transfer state conversion at low IE offsets. The same bending, however, is the origin of the barrier-less charge transfer state to free charge conversion. Our results provide a comprehensive picture of the photophysics of NFA-based blends, and show that sizeable bulk IE offsets are essential to design efficient BHJ OSCs based on low-bandgap NFAs.
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Affiliation(s)
- Safakath Karuthedath
- KAUST Solar Center, Physical Sciences and Engineering Division (PSE), Materials Science and Engineering Program (MSE), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Julien Gorenflot
- KAUST Solar Center, Physical Sciences and Engineering Division (PSE), Materials Science and Engineering Program (MSE), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Yuliar Firdaus
- KAUST Solar Center, Physical Sciences and Engineering Division (PSE), Materials Science and Engineering Program (MSE), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Neha Chaturvedi
- KAUST Solar Center, Physical Sciences and Engineering Division (PSE), Materials Science and Engineering Program (MSE), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Catherine S P De Castro
- KAUST Solar Center, Physical Sciences and Engineering Division (PSE), Materials Science and Engineering Program (MSE), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - George T Harrison
- KAUST Solar Center, Physical Sciences and Engineering Division (PSE), Materials Science and Engineering Program (MSE), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Jafar I Khan
- KAUST Solar Center, Physical Sciences and Engineering Division (PSE), Materials Science and Engineering Program (MSE), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | | | - Ahmed H Balawi
- KAUST Solar Center, Physical Sciences and Engineering Division (PSE), Materials Science and Engineering Program (MSE), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Top Archie Dela Peña
- KAUST Solar Center, Physical Sciences and Engineering Division (PSE), Materials Science and Engineering Program (MSE), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Wenlan Liu
- Max Planck Institute for Polymer Research, Mainz, Germany
| | - Ru-Ze Liang
- KAUST Solar Center, Physical Sciences and Engineering Division (PSE), Materials Science and Engineering Program (MSE), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Anirudh Sharma
- KAUST Solar Center, Physical Sciences and Engineering Division (PSE), Materials Science and Engineering Program (MSE), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Sri H K Paleti
- KAUST Solar Center, Physical Sciences and Engineering Division (PSE), Materials Science and Engineering Program (MSE), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Weimin Zhang
- KAUST Solar Center, Physical Sciences and Engineering Division (PSE), Materials Science and Engineering Program (MSE), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Yuanbao Lin
- KAUST Solar Center, Physical Sciences and Engineering Division (PSE), Materials Science and Engineering Program (MSE), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Erkki Alarousu
- KAUST Solar Center, Physical Sciences and Engineering Division (PSE), Materials Science and Engineering Program (MSE), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Sergei Lopatin
- Imaging and Characterization Core Laboratory, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Dalaver H Anjum
- Imaging and Characterization Core Laboratory, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Pierre M Beaujuge
- KAUST Solar Center, Physical Sciences and Engineering Division (PSE), Materials Science and Engineering Program (MSE), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Stefaan De Wolf
- KAUST Solar Center, Physical Sciences and Engineering Division (PSE), Materials Science and Engineering Program (MSE), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Iain McCulloch
- KAUST Solar Center, Physical Sciences and Engineering Division (PSE), Materials Science and Engineering Program (MSE), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
- Department of Chemistry, University of Oxford, Oxford, UK
| | - Thomas D Anthopoulos
- KAUST Solar Center, Physical Sciences and Engineering Division (PSE), Materials Science and Engineering Program (MSE), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Derya Baran
- KAUST Solar Center, Physical Sciences and Engineering Division (PSE), Materials Science and Engineering Program (MSE), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | | | - Frédéric Laquai
- KAUST Solar Center, Physical Sciences and Engineering Division (PSE), Materials Science and Engineering Program (MSE), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia.
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16
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Cha H, Li J, Li Y, Kim SO, Kim YH, Kwon SK. Effects of Bulk Heterojunction Morphology Control via Thermal Annealing on the Fill Factor of Anthracene-based Polymer Solar Cells. Macromol Res 2020. [DOI: 10.1007/s13233-020-8107-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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17
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Akaike K. Distributions of Potential and Contact-Induced Charges in Conventional Organic Photovoltaics. MATERIALS (BASEL, SWITZERLAND) 2020; 13:E2411. [PMID: 32456312 PMCID: PMC7288283 DOI: 10.3390/ma13102411] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 05/15/2020] [Accepted: 05/22/2020] [Indexed: 12/11/2022]
Abstract
The interfaces of dissimilar materials play central roles in photophysical events in organic photovoltaics (OPVs). Depth profiles of electrostatic potential and contact-induced charges determine the energy-level lineup of the frontier orbitals at electrode/organic and organic heterointerfaces. They are critical for the elementary processes in an OPV cell, such as generation and diffusion of free carriers. A simple electrostatic model describes the energetics in organic heterojunctions supported by an electrode, and experiments via photoelectron spectroscopy and the Kelvin probe method validate the potential distribution in the stacking direction of the device. A comparative study has clarified the significance of Fermi-level pinning and resulting electrostatic fields in determining the energy-level alignment. In this review, we discuss how parameters of device constituents affect the distributions of potential and the dark charges in conventional OPVs comprising metallophthalocyanine and C60 as donor and acceptor, respectively. The results of previous studies, together with additional numerical simulations, suggest that a number of the factors influence the depth profiles of the dark charge and potential, such as the work function of bottom materials, layer thickness, structural inhomogeneity at interfaces, top electrode, and stacking sequence.
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Affiliation(s)
- Kouki Akaike
- National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8565, Japan
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18
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Felekidis N, Melianas A, Kemerink M. The Role of Delocalization and Excess Energy in the Quantum Efficiency of Organic Solar Cells and the Validity of Optical Reciprocity Relations. J Phys Chem Lett 2020; 11:3563-3570. [PMID: 32301322 DOI: 10.1021/acs.jpclett.0c00945] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The photon energy dependence of long-range charge separation is studied for two prototypical polymer:fullerene systems. The internal quantum efficiency (IQE) of PCDTBT:PC61BM is experimentally shown to be independent of the excitation energy. In contrast, for TQ1:PC71BM the IQE is strongly energy-dependent for excitation energies close to charge transfer (CT) electroluminescence peak maximum while it becomes energy-independent at higher excitation energies. Kinetic Monte Carlo simulations reproduce the experimental IQE and reveal that the photon energy-dependence of the IQE is governed by charge delocalization. Efficient long-range separation at excitation energies corresponding to the CT electroluminescence peak maximum or lower requires an initial separation of the hole-electron pair by ∼4-5 nm, whereas delocalization is less important for charge separation at higher photon energies. Our modeling results suggest that a phenomenological reciprocity between CT electroluminescence and external quantum efficiency does not necessarily prove that commonly employed reciprocity relations between these spectra are valid from a fundamental perspective.
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Affiliation(s)
- N Felekidis
- Complex Materials and Devices, Department of Physics, Chemistry and Biology, Linköping University, 58183 Linköping, Sweden
| | - A Melianas
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - M Kemerink
- Complex Materials and Devices, Department of Physics, Chemistry and Biology, Linköping University, 58183 Linköping, Sweden
- Centre for Advanced Materials, University of Heidelberg, 69120 Heidelberg, Germany
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19
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Perdigón-Toro L, Zhang H, Markina A, Yuan J, Hosseini SM, Wolff CM, Zuo G, Stolterfoht M, Zou Y, Gao F, Andrienko D, Shoaee S, Neher D. Barrierless Free Charge Generation in the High-Performance PM6:Y6 Bulk Heterojunction Non-Fullerene Solar Cell. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1906763. [PMID: 31975446 DOI: 10.1002/adma.201906763] [Citation(s) in RCA: 97] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 12/19/2019] [Indexed: 05/22/2023]
Abstract
Organic solar cells are currently experiencing a second golden age thanks to the development of novel non-fullerene acceptors (NFAs). Surprisingly, some of these blends exhibit high efficiencies despite a low energy offset at the heterojunction. Herein, free charge generation in the high-performance blend of the donor polymer PM6 with the NFA Y6 is thoroughly investigated as a function of internal field, temperature and excitation energy. Results show that photocurrent generation is essentially barrierless with near-unity efficiency, regardless of excitation energy. Efficient charge separation is maintained over a wide temperature range, down to 100 K, despite the small driving force for charge generation. Studies on a blend with a low concentration of the NFA, measurements of the energetic disorder, and theoretical modeling suggest that CT state dissociation is assisted by the electrostatic interfacial field which for Y6 is large enough to compensate the Coulomb dissociation barrier.
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Affiliation(s)
- Lorena Perdigón-Toro
- Soft Matter Physics, Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam-Golm, Germany
- Disordered Semiconductor Optoelectronics, Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam-Golm, Germany
| | - Huotian Zhang
- Department of Physics, Chemistry and Biology (IFM), Linköping University, 581 83, Linköping, Sweden
| | - Anastasia Markina
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Jun Yuan
- College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, P. R. China
| | - Seyed Mehrdad Hosseini
- Disordered Semiconductor Optoelectronics, Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam-Golm, Germany
| | - Christian M Wolff
- Soft Matter Physics, Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam-Golm, Germany
| | - Guangzheng Zuo
- Soft Matter Physics, Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam-Golm, Germany
| | - Martin Stolterfoht
- Soft Matter Physics, Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam-Golm, Germany
| | - Yingping Zou
- College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, P. R. China
| | - Feng Gao
- Department of Physics, Chemistry and Biology (IFM), Linköping University, 581 83, Linköping, Sweden
| | - Denis Andrienko
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Safa Shoaee
- Disordered Semiconductor Optoelectronics, Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam-Golm, Germany
| | - Dieter Neher
- Soft Matter Physics, Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam-Golm, Germany
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20
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Sousa LE, Coropceanu V, da Silva Filho DA, Sini G. On the Physical Origins of Charge Separation at Donor–Acceptor Interfaces in Organic Solar Cells: Energy Bending versus Energy Disorder. ADVANCED THEORY AND SIMULATIONS 2020. [DOI: 10.1002/adts.201900230] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Leonardo Evaristo Sousa
- Theoretical and Structural Chemistry GroupState University of Goiás 75133‐050 Anápolis Brazil
| | - Veaceslav Coropceanu
- School of Chemistry and Biochemistry and Center for Organic Photonics and ElectronicsGeorgia Institute of Technology Atlanta GA 30332‐0400 USA
| | - Demétrio Antônio da Silva Filho
- Laboratoire de Physicochimie des Polymères et des Interfaces, EA 2528University of Cergy‐Pontoise 5 mail Gay‐Lussac 95031 Cergy‐Pontoise Cedex France
- Institute for Advanced StudiesUniversity of Cergy‐Pontoise 1 rue Descartes 95000 Neuville‐sur‐Oise France
- Institute of PhysicsUniversity of Brasilia 70919‐970 Brasília Brazil
| | - Gjergji Sini
- Laboratoire de Physicochimie des Polymères et des Interfaces, EA 2528University of Cergy‐Pontoise 5 mail Gay‐Lussac 95031 Cergy‐Pontoise Cedex France
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21
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Qin R, Guo D, Ma H, Yang J, Jiang Y, Liu H, Liu Z, Song J, Qin C. Effect of Molecular Structures of Donor Monomers of Polymers on Photovoltaic Properties. ACS OMEGA 2019; 4:19177-19182. [PMID: 31763541 PMCID: PMC6868602 DOI: 10.1021/acsomega.9b02476] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Accepted: 10/22/2019] [Indexed: 05/04/2023]
Abstract
This work investigates the photovoltaic properties of polymers that include different carbazole blocks as electron donors (D) but the same benzothiadiazole derivative as the electron acceptor (A). Five D-A copolymers are studied with ultrafast intramolecular exciton splitting and recombination dynamics to acquire the single-molecule structure and their photovoltaic performance relationship. The photovoltaic parameters such as energy level, optical band gap, and light-harvesting ability are highly dependent on the molecular structure of the donor monomer (including their appended flexible alkyl chain). Branched or linear alkyl groups on the same D block obviously vary the polymer steady-state absorption spectra and film morphology. For organic solar cells, this work allows tuning and control of the ultrafast dynamics, implying photovoltaic material design in the future.
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Affiliation(s)
- Ruiping Qin
- Key
Laboratory of Photovoltaic Materials of Henan Province, School
of Material Science and Engineering, Key Laboratory of Photovoltaic
Materials of Henan Province, School of Physics, and School of Physics, Henan Normal University, Xinxiang 453007, China
- E-mail: (R.Q.)
| | - Deen Guo
- Key
Laboratory of Photovoltaic Materials of Henan Province, School
of Material Science and Engineering, Key Laboratory of Photovoltaic
Materials of Henan Province, School of Physics, and School of Physics, Henan Normal University, Xinxiang 453007, China
| | - Heng Ma
- Key
Laboratory of Photovoltaic Materials of Henan Province, School
of Material Science and Engineering, Key Laboratory of Photovoltaic
Materials of Henan Province, School of Physics, and School of Physics, Henan Normal University, Xinxiang 453007, China
| | - Jien Yang
- Key
Laboratory of Photovoltaic Materials of Henan Province, School
of Material Science and Engineering, Key Laboratory of Photovoltaic
Materials of Henan Province, School of Physics, and School of Physics, Henan Normal University, Xinxiang 453007, China
| | - Yurong Jiang
- Key
Laboratory of Photovoltaic Materials of Henan Province, School
of Material Science and Engineering, Key Laboratory of Photovoltaic
Materials of Henan Province, School of Physics, and School of Physics, Henan Normal University, Xinxiang 453007, China
| | - Hairui Liu
- Key
Laboratory of Photovoltaic Materials of Henan Province, School
of Material Science and Engineering, Key Laboratory of Photovoltaic
Materials of Henan Province, School of Physics, and School of Physics, Henan Normal University, Xinxiang 453007, China
| | - Zhiyong Liu
- Key
Laboratory of Photovoltaic Materials of Henan Province, School
of Material Science and Engineering, Key Laboratory of Photovoltaic
Materials of Henan Province, School of Physics, and School of Physics, Henan Normal University, Xinxiang 453007, China
| | - Jian Song
- Key
Laboratory of Photovoltaic Materials of Henan Province, School
of Material Science and Engineering, Key Laboratory of Photovoltaic
Materials of Henan Province, School of Physics, and School of Physics, Henan Normal University, Xinxiang 453007, China
| | - ChaoChao Qin
- Key
Laboratory of Photovoltaic Materials of Henan Province, School
of Material Science and Engineering, Key Laboratory of Photovoltaic
Materials of Henan Province, School of Physics, and School of Physics, Henan Normal University, Xinxiang 453007, China
- E-mail: (C.Q.)
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22
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Kotadiya NB, Mondal A, Blom PWM, Andrienko D, Wetzelaer GJAH. A window to trap-free charge transport in organic semiconducting thin films. NATURE MATERIALS 2019; 18:1182-1186. [PMID: 31548633 DOI: 10.1038/s41563-019-0473-6] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 07/31/2019] [Indexed: 06/10/2023]
Abstract
Organic semiconductors, which serve as the active component in devices, such as solar cells, light-emitting diodes and field-effect transistors1, often exhibit highly unipolar charge transport, meaning that they predominantly conduct either electrons or holes. Here, we identify an energy window inside which organic semiconductors do not experience charge trapping for device-relevant thicknesses in the range of 100 to 300 nm, leading to trap-free charge transport of both carriers. When the ionization energy of a material surpasses 6 eV, hole trapping will limit the hole transport, whereas an electron affinity lower than 3.6 eV will give rise to trap-limited electron transport. When both energy levels are within this window, trap-free bipolar charge transport occurs. Based on simulations, water clusters are proposed to be the source of hole trapping. Organic semiconductors with energy levels situated within this energy window may lead to optoelectronic devices with enhanced performance. However, for blue-emitting light-emitting diodes, which require an energy gap of 3 eV, removing or disabling charge traps will remain a challenge.
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Affiliation(s)
| | - Anirban Mondal
- Max Planck Institute for Polymer Research, Mainz, Germany
| | - Paul W M Blom
- Max Planck Institute for Polymer Research, Mainz, Germany
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23
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Boehm BJ, Nguyen HTL, Huang DM. The interplay of interfaces, supramolecular assembly, and electronics in organic semiconductors. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:423001. [PMID: 31212263 DOI: 10.1088/1361-648x/ab2ac2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Organic semiconductors, which include a diverse range of carbon-based small molecules and polymers with interesting optoelectronic properties, offer many advantages over conventional inorganic semiconductors such as silicon and are growing in importance in electronic applications. Although these materials are now the basis of a lucrative industry in electronic displays, many promising applications such as photovoltaics remain largely untapped. One major impediment to more rapid development and widespread adoption of organic semiconductor technologies is that device performance is not easily predicted from the chemical structure of the constituent molecules. Fundamentally, this is because organic semiconductor molecules, unlike inorganic materials, interact by weak non-covalent forces, resulting in significant structural disorder that can strongly impact electronic properties. Nevertheless, directional forces between generally anisotropic organic-semiconductor molecules, combined with translational symmetry breaking at interfaces, can be exploited to control supramolecular order and consequent electronic properties in these materials. This review surveys recent advances in understanding of supramolecular assembly at organic-semiconductor interfaces and its impact on device properties in a number of applications, including transistors, light-emitting diodes, and photovoltaics. Recent progress and challenges in computer simulations of supramolecular assembly and orientational anisotropy at these interfaces is also addressed.
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Affiliation(s)
- Belinda J Boehm
- Department of Chemistry, School of Physical Sciences, The University of Adelaide, SA 5005, Australia
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24
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Schwarze M, Schellhammer KS, Ortstein K, Benduhn J, Gaul C, Hinderhofer A, Perdigón Toro L, Scholz R, Kublitski J, Roland S, Lau M, Poelking C, Andrienko D, Cuniberti G, Schreiber F, Neher D, Vandewal K, Ortmann F, Leo K. Impact of molecular quadrupole moments on the energy levels at organic heterojunctions. Nat Commun 2019; 10:2466. [PMID: 31165738 PMCID: PMC6549189 DOI: 10.1038/s41467-019-10435-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 05/11/2019] [Indexed: 11/09/2022] Open
Abstract
The functionality of organic semiconductor devices crucially depends on molecular energies, namely the ionisation energy and the electron affinity. Ionisation energy and electron affinity values of thin films are, however, sensitive to film morphology and composition, making their prediction challenging. In a combined experimental and simulation study on zinc-phthalocyanine and its fluorinated derivatives, we show that changes in ionisation energy as a function of molecular orientation in neat films or mixing ratio in blends are proportional to the molecular quadrupole component along the π-π-stacking direction. We apply these findings to organic solar cells and demonstrate how the electrostatic interactions can be tuned to optimise the energy of the charge-transfer state at the donor-acceptor interface and the dissociation barrier for free charge carrier generation. The confirmation of the correlation between interfacial energies and quadrupole moments for other materials indicates its relevance for small molecules and polymers.
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Affiliation(s)
- Martin Schwarze
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP), Technische Universität Dresden, 01069, Dresden, Germany.
| | - Karl Sebastian Schellhammer
- Institute for Materials Science, Max-Bergmann Center of Biomaterials and Dresden Center for Computational Materials Science, Technische Universität Dresden, 01069, Dresden, Germany.,Center for Advancing Electronics Dresden, Technische Universität Dresden, 01069, Dresden, Germany
| | - Katrin Ortstein
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP), Technische Universität Dresden, 01069, Dresden, Germany
| | - Johannes Benduhn
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP), Technische Universität Dresden, 01069, Dresden, Germany
| | - Christopher Gaul
- Center for Advancing Electronics Dresden, Technische Universität Dresden, 01069, Dresden, Germany
| | - Alexander Hinderhofer
- Institute of Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076, Tübingen, Germany
| | - Lorena Perdigón Toro
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany
| | - Reinhard Scholz
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP), Technische Universität Dresden, 01069, Dresden, Germany
| | - Jonas Kublitski
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP), Technische Universität Dresden, 01069, Dresden, Germany
| | - Steffen Roland
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany
| | - Matthias Lau
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP), Technische Universität Dresden, 01069, Dresden, Germany
| | - Carl Poelking
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Denis Andrienko
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Gianaurelio Cuniberti
- Institute for Materials Science, Max-Bergmann Center of Biomaterials and Dresden Center for Computational Materials Science, Technische Universität Dresden, 01069, Dresden, Germany
| | - Frank Schreiber
- Institute of Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076, Tübingen, Germany
| | - Dieter Neher
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany
| | - Koen Vandewal
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP), Technische Universität Dresden, 01069, Dresden, Germany.,Instituut voor Materiaalonderzoek (IMO), Hasselt University, Wetenschapspark 1, 3590, Diepenbeek, Belgium
| | - Frank Ortmann
- Center for Advancing Electronics Dresden, Technische Universität Dresden, 01069, Dresden, Germany.
| | - Karl Leo
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP), Technische Universität Dresden, 01069, Dresden, Germany.
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25
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Koçak O, Duru IP, Yavuz I. Charge Transfer and Interface Effects in Co‐Assembled Circular Donor/Acceptor Complexes for Organic Photovoltaics. ADVANCED THEORY AND SIMULATIONS 2019. [DOI: 10.1002/adts.201800194] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Olkan Koçak
- Department of PhysicsMarmara University 34722 Ziverbey Istanbul Turkey
| | - Izzet Paruğ Duru
- Department of PhysicsMarmara University 34722 Ziverbey Istanbul Turkey
| | - Ilhan Yavuz
- Department of PhysicsMarmara University 34722 Ziverbey Istanbul Turkey
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26
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Hume PA, Monks JP, Pop F, Davies ES, MacKenzie RCI, Amabilino DB. Self-Assembly of Chiral-at-End Diketopyrrolopyrroles: Symmetry Dependent Solution and Film Optical Activity and Photovoltaic Performance. Chemistry 2018; 24:14461-14469. [DOI: 10.1002/chem.201802610] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Indexed: 11/08/2022]
Affiliation(s)
- Paul A. Hume
- School of Chemistry; University of Nottingham; University Park NG7 2RD UK
- Present address: School of Chemical Sciences; The University of Auckland; 23 Symonds Street Auckland 1010 New Zealand
| | - James P. Monks
- School of Chemistry; University of Nottingham; University Park NG7 2RD UK
- The GSK Carbon Neutral Laboratories for Sustainable Chemistry; University of Nottingham; Jubilee Campus, Triumph Road Nottingham NG7 2TU UK
| | - Flavia Pop
- School of Chemistry; University of Nottingham; University Park NG7 2RD UK
- Present address: Laboratoire MOLTECH-Anjou; UMR 6200 CNRS UFR Sciences, Bât. K; 2 bd. Lavoisier 49045 Angers France
| | - E. Stephen Davies
- School of Chemistry; University of Nottingham; University Park NG7 2RD UK
| | | | - David B. Amabilino
- School of Chemistry; University of Nottingham; University Park NG7 2RD UK
- The GSK Carbon Neutral Laboratories for Sustainable Chemistry; University of Nottingham; Jubilee Campus, Triumph Road Nottingham NG7 2TU UK
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27
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Kurpiers J, Ferron T, Roland S, Jakoby M, Thiede T, Jaiser F, Albrecht S, Janietz S, Collins BA, Howard IA, Neher D. Probing the pathways of free charge generation in organic bulk heterojunction solar cells. Nat Commun 2018; 9:2038. [PMID: 29795114 PMCID: PMC5966440 DOI: 10.1038/s41467-018-04386-3] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 04/24/2018] [Indexed: 11/30/2022] Open
Abstract
The fact that organic solar cells perform efficiently despite the low dielectric constant of most photoactive blends initiated a long-standing debate regarding the dominant pathways of free charge formation. Here, we address this issue through the accurate measurement of the activation energy for free charge photogeneration over a wide range of photon energy, using the method of time-delayed collection field. For our prototypical low bandgap polymer:fullerene blends, we find that neither the temperature nor the field dependence of free charge generation depend on the excitation energy, ruling out an appreciable contribution to free charge generation though hot carrier pathways. On the other hand, activation energies are on the order of the room temperature thermal energy for all studied blends. We conclude that charge generation in such devices proceeds through thermalized charge transfer states, and that thermal energy is sufficient to separate most of these states into free charges. Contradictory models are being debated on the dominant pathways of charge generation in organic solar cells. Here Kurpiers et al. determine the activation energy for this fundamental process and reveal that the main channel is via thermalized charge transfer states instead of hot exciton dissociation.
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Affiliation(s)
- Jona Kurpiers
- Institute of Physics and Astronomy, Soft Matter Physics, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam-Golm, Germany
| | - Thomas Ferron
- Department of Physics and Astronomy, Washington State University, 100 Dairy Road, Pullman, WA, 99164, USA
| | - Steffen Roland
- Institute of Physics and Astronomy, Soft Matter Physics, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam-Golm, Germany
| | - Marius Jakoby
- Karlsruhe Institute of Technology (KIT), Institute of Microstructure Technology (IMT), Hermann-von-Helmholtz Platz-1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Tobias Thiede
- Institute of Physics and Astronomy, Soft Matter Physics, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam-Golm, Germany
| | - Frank Jaiser
- Institute of Physics and Astronomy, Soft Matter Physics, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam-Golm, Germany
| | - Steve Albrecht
- Helmholtz-Zentrum Berlin für Materialien und Energie, Nachwuchsgruppe Perowskit Tandemsolarzellen, Kekuléstraße 5, 12489, Berlin, Germany
| | - Silvia Janietz
- Fraunhofer IAP, Polymere und Elektronik, Geiselbergstraße 69, 14476, Potsdam-Golm, Germany
| | - Brian A Collins
- Department of Physics and Astronomy, Washington State University, 100 Dairy Road, Pullman, WA, 99164, USA
| | - Ian A Howard
- Karlsruhe Institute of Technology (KIT), Institute of Microstructure Technology (IMT), Hermann-von-Helmholtz Platz-1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Dieter Neher
- Institute of Physics and Astronomy, Soft Matter Physics, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam-Golm, Germany.
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28
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Tietze ML, Benduhn J, Pahner P, Nell B, Schwarze M, Kleemann H, Krammer M, Zojer K, Vandewal K, Leo K. Elementary steps in electrical doping of organic semiconductors. Nat Commun 2018; 9:1182. [PMID: 29563497 PMCID: PMC5862893 DOI: 10.1038/s41467-018-03302-z] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 01/29/2018] [Indexed: 11/12/2022] Open
Abstract
Fermi level control by doping is established since decades in inorganic semiconductors and has been successfully introduced in organic semiconductors. Despite its commercial success in the multi-billion OLED display business, molecular doping is little understood, with its elementary steps controversially discussed and mostly-empirical-materials design. Particularly puzzling is the efficient carrier release, despite a presumably large Coulomb barrier. Here we quantitatively investigate doping as a two-step process, involving single-electron transfer from donor to acceptor molecules and subsequent dissociation of the ground-state integer-charge transfer complex (ICTC). We show that carrier release by ICTC dissociation has an activation energy of only a few tens of meV, despite a Coulomb binding of several 100 meV. We resolve this discrepancy by taking energetic disorder into account. The overall doping process is explained by an extended semiconductor model in which occupation of ICTCs causes the classically known reserve regime at device-relevant doping concentrations. Molecular doping is routinely used in organic semiconductor devices nowadays, but the physics at play remains unclarified. Tietze et al. describe it as a two-step process and show it costs little, energetically, to dissociate charge transfer complexes due to energetic disorder of organic semiconductors.
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Affiliation(s)
- Max L Tietze
- Dresden Integrated Center for Applied Physics and Photonic Materials, Technische Universität Dresden, Nöthnitzer Strasse 61, 01187, Dresden, Germany. .,Physical Science and Engineering Division, KAUST Solar Center, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia. .,Department of Microbial and Molecular Systems, Centre for Surface Chemistry and Catalysis, KU Leuven-University of Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium.
| | - Johannes Benduhn
- Dresden Integrated Center for Applied Physics and Photonic Materials, Technische Universität Dresden, Nöthnitzer Strasse 61, 01187, Dresden, Germany
| | - Paul Pahner
- Dresden Integrated Center for Applied Physics and Photonic Materials, Technische Universität Dresden, Nöthnitzer Strasse 61, 01187, Dresden, Germany
| | - Bernhard Nell
- Dresden Integrated Center for Applied Physics and Photonic Materials, Technische Universität Dresden, Nöthnitzer Strasse 61, 01187, Dresden, Germany
| | - Martin Schwarze
- Dresden Integrated Center for Applied Physics and Photonic Materials, Technische Universität Dresden, Nöthnitzer Strasse 61, 01187, Dresden, Germany
| | - Hans Kleemann
- Dresden Integrated Center for Applied Physics and Photonic Materials, Technische Universität Dresden, Nöthnitzer Strasse 61, 01187, Dresden, Germany
| | - Markus Krammer
- NAWI Graz, Institute of Solid State Physics, Graz University of Technology, Petersgasse 16, 8010, Graz, Austria
| | - Karin Zojer
- NAWI Graz, Institute of Solid State Physics, Graz University of Technology, Petersgasse 16, 8010, Graz, Austria
| | - Koen Vandewal
- Dresden Integrated Center for Applied Physics and Photonic Materials, Technische Universität Dresden, Nöthnitzer Strasse 61, 01187, Dresden, Germany.,Instituut voor Materiaalonderzoek, Hasselt University, Wetenschapspark 1, 3590, Diepenbeek, Belgium
| | - Karl Leo
- Dresden Integrated Center for Applied Physics and Photonic Materials, Technische Universität Dresden, Nöthnitzer Strasse 61, 01187, Dresden, Germany.
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29
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Few S, Chia C, Teo D, Kirkpatrick J, Nelson J. The impact of chemical structure and molecular packing on the electronic polarisation of fullerene arrays. Phys Chem Chem Phys 2018; 19:18709-18720. [PMID: 28696470 DOI: 10.1039/c7cp00317j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electronic polarisation contributes to the electronic landscape as seen by separating charges in organic materials. The nature of electronic polarisation depends on the polarisability, density, and arrangement of polarisable molecules. In this paper, we introduce a microscopic, coarse-grained model in which we treat each molecule as a polarisable site, and use an array of such polarisable dipoles to calculate the electric field and associated energy of any arrangement of charges in the medium. The model incorporates chemical structure via the molecular polarisability and molecular packing patterns via the structure of the array. We use this model to calculate energies of charge pairs undergoing separation in finite fullerene lattices of different chemical and crystal structures. The effective dielectric constants that we estimate from this approach are in good quantitative agreement with those measured experimentally in C60 and phenyl-C61-butyric acid methyl ester (PCBM) films, but we find significant differences in dielectric constant depending on packing and on direction of separation, which we rationalise in terms of density of polarisable fullerene cages in regions of high field. In general, we find lattices containing molecules of more isotropic polarisability tensors exhibit higher dielectric constants. By exploring several model systems we conclude that differences in molecular polarisability (and therefore, chemical structure) appear to be less important than differences in molecular packing and separation direction in determining the energetic landscape for charge separation. We note that the results are relevant for finite lattices, but not necessarily for infinite systems. We propose that the model could be used to design molecular systems for effective electronic screening.
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Affiliation(s)
- Sheridan Few
- Centre for Plastic Electronics, Department of Physics, Imperial College London, London SW7 2AZ, UK.
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30
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Plehn T, Ziemann D, May V. Atomistic Simulations of Charge Separation at a Nanohybrid Interface: Relevance of Photoinduced Initial State Preparation. J Phys Chem Lett 2018; 9:209-215. [PMID: 29265820 DOI: 10.1021/acs.jpclett.7b02772] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Charge separation kinetics at a nanohybrid interface are investigated in their dependence on ultrafast optical excitation. A prototypical organic/inorganic interface is considered. It is formed by a vertical stacking of 20 para-sexiphenyl molecules physisorbed on a ZnO nanocluster of 3783 atoms. A first principle parametrized Hamiltonian is employed, and the photoinduced subpicosecond evolution of Frenkel-excitons in the organic part is analyzed besides the formation of charge separated states across the interface. The interface absorption spectrum is calculated. Together, the data indicate that the charge separation is based on the direct excitation of the charge separated states but also on the migration of created Frenkel excitons to the interface with subsequent decay. Further, the photoinduced interface dynamics are compared with data resulting from direct set-ups of an initially excited state. Mostly such set-ups lead to substantially different charge separation processes.
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Affiliation(s)
- Thomas Plehn
- Institute of Physics, Humboldt-University at Berlin , Newtonstraße 15, D-12489 Berlin, Germany
| | - Dirk Ziemann
- Institute of Physics, Humboldt-University at Berlin , Newtonstraße 15, D-12489 Berlin, Germany
| | - Volkhard May
- Institute of Physics, Humboldt-University at Berlin , Newtonstraße 15, D-12489 Berlin, Germany
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31
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Nakano K, Tajima K. Organic Planar Heterojunctions: From Models for Interfaces in Bulk Heterojunctions to High-Performance Solar Cells. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1603269. [PMID: 27885716 DOI: 10.1002/adma.201603269] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 08/30/2016] [Indexed: 05/28/2023]
Abstract
Recent progress regarding planar heterojunctions (PHJs) is reviewed, with respect to the fundamental understanding of the photophysical processes at the donor/acceptor interfaces in organic photovoltaic devices (OPVs). The current state of OPV research is summarized and the advantages of PHJs as models for exploring the relationship between organic interfaces and device characteristics described. The preparation methods and the characterization of PHJ structures to provide key points for the appropriate handling of PHJs. Next, we describe the effects of the donor/acceptor interface on each photoelectric conversion process are reviewed by examining various PHJ systems to clarify what is currently known and not known. Finally, it is discussed how we the knowledge obtained by studies of PHJs can be used to overcome the current limits of OPV efficiency.
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Affiliation(s)
- Kyohei Nakano
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Keisuke Tajima
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan
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32
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Volpi R, Linares M. Study of the cold charge transfer state separation at the TQ1/PC 71 BM interface. J Comput Chem 2017; 38:1039-1048. [PMID: 28318028 DOI: 10.1002/jcc.24776] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 02/03/2017] [Accepted: 02/04/2017] [Indexed: 11/09/2022]
Abstract
Charge transfer (CT) state separation is one of the most critical processes in the functioning of an organic solar cell. In this article, we study a bilayer of TQ1 and PC71 BM molecules presenting disorder at the interface, obtained by means of Molecular Dynamics. The study of the CT state splitting can be first analyzed through the CT state splitting diagram, introduced in a previous work. Through this analysis, we identify the possibility of CT state splitting within Marcus Theory in function of the electric field. Once the right range of electric fields has been identified, we perform Kinetic Monte Carlo simulations to estimate percentages and times for the CT state splitting and the free charge carriers collection. Statistical information extracted from these simulations allows us to highlight the importance of polarization and to test the limits of the predictions given by the CT state splitting diagram. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Riccardo Volpi
- Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, SE-581 83, Sweden
| | - Mathieu Linares
- Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, SE-581 83, Sweden.,Swedish e-Science Research Centre (SeRC), Linköping University, Linköping, SE-581 83, Sweden
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33
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Plehn T, May V. Charge and energy migration in molecular clusters: A stochastic Schrödinger equation approach. J Chem Phys 2017; 146:034107. [PMID: 28109221 DOI: 10.1063/1.4973886] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The performance of stochastic Schrödinger equations for simulating dynamic phenomena in large scale open quantum systems is studied. Going beyond small system sizes, commonly used master equation approaches become inadequate. In this regime, wave function based methods profit from their inherent scaling benefit and present a promising tool to study, for example, exciton and charge carrier dynamics in huge and complex molecular structures. In the first part of this work, a strict analytic derivation is presented. It starts with the finite temperature reduced density operator expanded in coherent reservoir states and ends up with two linear stochastic Schrödinger equations. Both equations are valid in the weak and intermediate coupling limit and can be properly related to two existing approaches in literature. In the second part, we focus on the numerical solution of these equations. The main issue is the missing norm conservation of the wave function propagation which may lead to numerical discrepancies. To illustrate this, we simulate the exciton dynamics in the Fenna-Matthews-Olson complex in direct comparison with the data from literature. Subsequently a strategy for the proper computational handling of the linear stochastic Schrödinger equation is exposed particularly with regard to large systems. Here, we study charge carrier transfer kinetics in realistic hybrid organic/inorganic para-sexiphenyl/ZnO systems of different extension.
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Affiliation(s)
- Thomas Plehn
- Institute of Physics, Humboldt-University at Berlin, Newtonstraße 15, D-12489 Berlin, Germany
| | - Volkhard May
- Institute of Physics, Humboldt-University at Berlin, Newtonstraße 15, D-12489 Berlin, Germany
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34
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Steiner F, Poelking C, Niedzialek D, Andrienko D, Nelson J. Influence of orientation mismatch on charge transport across grain boundaries in tri-isopropylsilylethynyl (TIPS) pentacene thin films. Phys Chem Chem Phys 2017; 19:10854-10862. [DOI: 10.1039/c6cp06436a] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present a multi-scale model for charge transport across grain boundaries in molecular electronic materials that incorporates packing disorder, electrostatic and polarisation effects.
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Affiliation(s)
- Florian Steiner
- Department of Physics and Centre for Plastic Electronics
- Imperial College London
- London SW7 2AZ
- UK
| | - Carl Poelking
- Max Planck Institute for Polymer Research
- 55128 Mainz
- Germany
| | - Dorota Niedzialek
- Department of Physics and Centre for Plastic Electronics
- Imperial College London
- London SW7 2AZ
- UK
| | | | - Jenny Nelson
- Department of Physics and Centre for Plastic Electronics
- Imperial College London
- London SW7 2AZ
- UK
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35
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Charge Carrier Generation, Recombination, and Extraction in Polymer–Fullerene Bulk Heterojunction Organic Solar Cells. ELEMENTARY PROCESSES IN ORGANIC PHOTOVOLTAICS 2017. [DOI: 10.1007/978-3-319-28338-8_11] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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36
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D'Avino G, Muccioli L, Castet F, Poelking C, Andrienko D, Soos ZG, Cornil J, Beljonne D. Electrostatic phenomena in organic semiconductors: fundamentals and implications for photovoltaics. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:433002. [PMID: 27603960 DOI: 10.1088/0953-8984/28/43/433002] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
This review summarizes the current understanding of electrostatic phenomena in ordered and disordered organic semiconductors, outlines numerical schemes developed for quantitative evaluation of electrostatic and induction contributions to ionization potentials and electron affinities of organic molecules in a solid state, and illustrates two applications of these techniques: interpretation of photoelectron spectroscopy of thin films and energetics of heterointerfaces in organic solar cells.
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Affiliation(s)
- Gabriele D'Avino
- Laboratory for the Chemistry of Novel Materials, Université de Mons, 7000 Mons, Belgium
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37
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Jiang B, Yao J, Zhan C. Modulating PCBM-Acceptor Crystallinity and Organic Solar Cell Performance by Judiciously Designing Small-Molecule Mainchain End-Capping Units. ACS APPLIED MATERIALS & INTERFACES 2016; 8:26058-26065. [PMID: 27618875 DOI: 10.1021/acsami.6b08407] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In this article, we report that the bulk-size and electron-donating/electron-accepting nature of moieties, which are end-capping onto small-molecule donor mainchain, not only modulate the donor's absorption, molecular frontier orbitals, and phase ordering, but also effectively tune the PC71BM-acceptor phase crystallinity. Compared to the electron-deficient trifluoromethyl (SM-CF3) units on the diketopyrrolopyrrole (DPP) small molecule mainchain ends, the electron-rich methoxyl (SM-OCH3) units ending on the same mainchain help improve the PC71BM-acceptor phase short-range ordering. As a result, the -OCH3 capping small-molecule displays larger short-circuit current density (Jsc) when blended with PC71BM (10.72 ± 0.22 vs. 16.15 ± 0.53 mA/cm2). However, the electron-donating nature of -OCH3 raises the donor HOMO level, which leads to a quite small open-circuit voltage (Voc) (0.624 vs. 0.881 V). Replacement of the -OCH3 with the large and weak electron-donating aromatic carbazolyl (SM-Cz) ones affords the small molecule of SM-Cz. The SM-Cz:PC71BM system affords a high Voc of 0.846 V and a large Jsc of 13.33 ± 0.34 mA/cm2 after thermal annealing, and hence gives a larger power conversion efficiency (PCE) of 6.26 ± 0.13%, which is among the top values achieved so far from the DPP molecules. Taken together, these results demonstrate that engineering the end-capping units on small-molecule donor mainchain can effectively modulate the organic solar cell performance.
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Affiliation(s)
- Bo Jiang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, P.R. China
| | - Jiannian Yao
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, P.R. China
| | - Chuanlang Zhan
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, P.R. China
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38
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Volpi R, Nassau R, Nørby MS, Linares M. Theoretical Study of the Charge-Transfer State Separation within Marcus Theory: The C60-Anthracene Case Study. ACS APPLIED MATERIALS & INTERFACES 2016; 8:24722-24736. [PMID: 27561228 DOI: 10.1021/acsami.6b06645] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We study, within Marcus theory, the possibility of the charge-transfer (CT) state splitting at organic interfaces and a subsequent transport of the free charge carriers to the electrodes. As a case study we analyze model anthracene-C60 interfaces. Kinetic Monte Carlo (KMC) simulations on the cold CT state were performed at a range of applied electric fields, and with the fields applied at a range of angles to the interface to simulate the action of the electric field in a bulk heterojunction (BHJ) interface. The results show that the inclusion of polarization in our model increases CT state dissociation and charge collection. The effect of the electric field on CT state splitting and free charge carrier conduction is analyzed in detail with and without polarization. Also, depending on the relative orientation of the anthracene and C60 molecules at the interface, CT state splitting shows different behavior with respect to both applied field strength and applied field angle. The importance of the hot CT in helping the charge carrier dissociation is also analyzed in our scheme.
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Affiliation(s)
- Riccardo Volpi
- Department of Physics, Chemistry and Biology (IFM), Linköping University , SE-581 83 Linköping, Sweden
- Swedish e-Science Research Centre (SeRC), Linköping University , SE-581 83 Linköping, Sweden
| | - Racine Nassau
- Department of Physics, Chemistry and Biology (IFM), Linköping University , SE-581 83 Linköping, Sweden
| | - Morten Steen Nørby
- Department of Physics, Chemistry and Biology (IFM), Linköping University , SE-581 83 Linköping, Sweden
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark , DK-5230 Odense M, Denmark
| | - Mathieu Linares
- Department of Physics, Chemistry and Biology (IFM), Linköping University , SE-581 83 Linköping, Sweden
- Swedish e-Science Research Centre (SeRC), Linköping University , SE-581 83 Linköping, Sweden
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39
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Poelking C, Andrienko D. Long-Range Embedding of Molecular Ions and Excitations in a Polarizable Molecular Environment. J Chem Theory Comput 2016; 12:4516-23. [DOI: 10.1021/acs.jctc.6b00599] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Carl Poelking
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
- Heidelberg Graduate School of Fundamental Physics, INF 226, 69120 Heidelberg, Germany
| | - Denis Andrienko
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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40
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Schwarze M, Tress W, Beyer B, Gao F, Scholz R, Poelking C, Ortstein K, Günther AA, Kasemann D, Andrienko D, Leo K. Band structure engineering in organic semiconductors. Science 2016; 352:1446-9. [PMID: 27313043 DOI: 10.1126/science.aaf0590] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 04/13/2016] [Indexed: 01/25/2023]
Abstract
A key breakthrough in modern electronics was the introduction of band structure engineering, the design of almost arbitrary electronic potential structures by alloying different semiconductors to continuously tune the band gap and band-edge energies. Implementation of this approach in organic semiconductors has been hindered by strong localization of the electronic states in these materials. We show that the influence of so far largely ignored long-range Coulomb interactions provides a workaround. Photoelectron spectroscopy confirms that the ionization energies of crystalline organic semiconductors can be continuously tuned over a wide range by blending them with their halogenated derivatives. Correspondingly, the photovoltaic gap and open-circuit voltage of organic solar cells can be continuously tuned by the blending ratio of these donors.
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Affiliation(s)
- Martin Schwarze
- Institut für Angewandte Photophysik, Technische Universität Dresden, 01069 Dresden, Germany
| | - Wolfgang Tress
- Biomolecular and Organic Electronics, IFM, Linköping University, 58183 Linköping, Sweden
| | - Beatrice Beyer
- Fraunhofer Institute for Electron Beam, Plasma Technology and COMEDD, 01109 Dresden, Germany
| | - Feng Gao
- Biomolecular and Organic Electronics, IFM, Linköping University, 58183 Linköping, Sweden
| | - Reinhard Scholz
- Institut für Angewandte Photophysik, Technische Universität Dresden, 01069 Dresden, Germany. Dresden Center for Computational Materials Science, Technische Universität Dresden, 01062 Dresden, Germany
| | - Carl Poelking
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Katrin Ortstein
- Institut für Angewandte Photophysik, Technische Universität Dresden, 01069 Dresden, Germany
| | - Alrun A Günther
- Institut für Angewandte Photophysik, Technische Universität Dresden, 01069 Dresden, Germany
| | - Daniel Kasemann
- Institut für Angewandte Photophysik, Technische Universität Dresden, 01069 Dresden, Germany
| | - Denis Andrienko
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Karl Leo
- Institut für Angewandte Photophysik, Technische Universität Dresden, 01069 Dresden, Germany.
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41
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Affiliation(s)
- Koen Vandewal
- Institut für Angewandte Photophysik, Technische Universität Dresden, 01062, Dresden, Germany;
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42
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D'Avino G, Muccioli L, Olivier Y, Beljonne D. Charge Separation and Recombination at Polymer-Fullerene Heterojunctions: Delocalization and Hybridization Effects. J Phys Chem Lett 2016; 7:536-40. [PMID: 26785294 DOI: 10.1021/acs.jpclett.5b02680] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
We address charge separation and recombination in polymer/fullerene solar cells with a multiscale modeling built from accurate atomistic inputs and accounting for disorder, interface electrostatics and genuine quantum effects on equal footings. Our results show that bound localized charge transfer states at the interface coexist with a large majority of thermally accessible delocalized space-separated states that can be also reached by direct photoexcitation, thanks to their strong hybridization with singlet polymer excitons. These findings reconcile the recent experimental reports of ultrafast exciton separation ("hot" process) with the evidence that high quantum yields do not require excess electronic or vibrational energy ("cold" process), and show that delocalization, by shifting the density of charge transfer states toward larger effective electron-hole radii, may reduce energy losses through charge recombination.
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Affiliation(s)
- Gabriele D'Avino
- Laboratory for Chemistry of Novel Materials, University of Mons , 7000 Mons, Belgium
| | - Luca Muccioli
- Laboratoire de Chimie des Polymères Organiques, UMR 5629, University of Bordeaux , 33607 Pessac, France
| | - Yoann Olivier
- Laboratory for Chemistry of Novel Materials, University of Mons , 7000 Mons, Belgium
| | - David Beljonne
- Laboratory for Chemistry of Novel Materials, University of Mons , 7000 Mons, Belgium
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43
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Wang Q, Zhang S, Xu B, Ye L, Yao H, Cui Y, Zhang H, Yuan W, Hou J. Effectively Improving Extinction Coefficient of Benzodithiophene and Benzodithiophenedione-based Photovoltaic Polymer by Grafting Alkylthio Functional Groups. Chem Asian J 2016; 11:2650-2655. [DOI: 10.1002/asia.201501387] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Revised: 01/12/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Qi Wang
- Department of Chemistry; School of Chemistry and Biology Engineering; University of Science and Technology Beijing; 30 Xueyuan Road Beijing 100083 China
- State Key Laboratory of Polymer Physics and Chemistry; Beijing National Laboratory for Molecular Sciences; Institute of Chemistry, Chinese Academy of Sciences; Zhongguancun North First Street 2 Beijing 100190 China
| | - Shaoqing Zhang
- Department of Chemistry; School of Chemistry and Biology Engineering; University of Science and Technology Beijing; 30 Xueyuan Road Beijing 100083 China
- State Key Laboratory of Polymer Physics and Chemistry; Beijing National Laboratory for Molecular Sciences; Institute of Chemistry, Chinese Academy of Sciences; Zhongguancun North First Street 2 Beijing 100190 China
| | - Bowei Xu
- State Key Laboratory of Polymer Physics and Chemistry; Beijing National Laboratory for Molecular Sciences; Institute of Chemistry, Chinese Academy of Sciences; Zhongguancun North First Street 2 Beijing 100190 China
| | - Long Ye
- State Key Laboratory of Polymer Physics and Chemistry; Beijing National Laboratory for Molecular Sciences; Institute of Chemistry, Chinese Academy of Sciences; Zhongguancun North First Street 2 Beijing 100190 China
| | - Huifeng Yao
- State Key Laboratory of Polymer Physics and Chemistry; Beijing National Laboratory for Molecular Sciences; Institute of Chemistry, Chinese Academy of Sciences; Zhongguancun North First Street 2 Beijing 100190 China
| | - Yong Cui
- Department of Chemistry; School of Chemistry and Biology Engineering; University of Science and Technology Beijing; 30 Xueyuan Road Beijing 100083 China
- State Key Laboratory of Polymer Physics and Chemistry; Beijing National Laboratory for Molecular Sciences; Institute of Chemistry, Chinese Academy of Sciences; Zhongguancun North First Street 2 Beijing 100190 China
| | - Hao Zhang
- State Key Laboratory of Polymer Physics and Chemistry; Beijing National Laboratory for Molecular Sciences; Institute of Chemistry, Chinese Academy of Sciences; Zhongguancun North First Street 2 Beijing 100190 China
| | - Wenxia Yuan
- Department of Chemistry; School of Chemistry and Biology Engineering; University of Science and Technology Beijing; 30 Xueyuan Road Beijing 100083 China
| | - Jianhui Hou
- Department of Chemistry; School of Chemistry and Biology Engineering; University of Science and Technology Beijing; 30 Xueyuan Road Beijing 100083 China
- State Key Laboratory of Polymer Physics and Chemistry; Beijing National Laboratory for Molecular Sciences; Institute of Chemistry, Chinese Academy of Sciences; Zhongguancun North First Street 2 Beijing 100190 China
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44
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Kordt P, Stodtmann S, Badinski A, Al Helwi M, Lennartz C, Andrienko D. Parameter-free continuous drift-diffusion models of amorphous organic semiconductors. Phys Chem Chem Phys 2015; 17:22778-83. [PMID: 26267617 DOI: 10.1039/c5cp03605d] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Continuous drift-diffusion models are routinely used to optimize organic semiconducting devices. Material properties are incorporated into these models via dependencies of diffusion constants, mobilities, and injection barriers on temperature, charge density, and external field. The respective expressions are often provided by the generic Gaussian disorder models, parametrized on experimental data. We show that this approach is limited by the fixed range of applicability of analytic expressions as well as approximations inherent to lattice models. To overcome these limitations we propose a scheme which first tabulates simulation results performed on small-scale off-lattice models, corrects for finite size effects, and then uses the tabulated mobility values to solve the drift-diffusion equations. The scheme is tested on DPBIC, a state of the art hole conductor for organic light emitting diodes. We find a good agreement between simulated and experimentally measured current-voltage characteristics for different film thicknesses and temperatures.
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Affiliation(s)
- Pascal Kordt
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
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