1
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Bae HS, Ahn DH, Song JW. Why Does the Optimal Tuning Method of the Range Separation Parameter of a Long-Range Corrected Density Functional Fail in Intramolecular Charge Transfer Excitation Calculations? Molecules 2024; 29:4423. [PMID: 39339418 DOI: 10.3390/molecules29184423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2024] [Revised: 09/11/2024] [Accepted: 09/13/2024] [Indexed: 09/30/2024] Open
Abstract
We performed intra- and intermolecular charge transfer (CT) excitation energy calculations of (a) conjugated carbon chain [H2N-(CH=CH)n-X] and (b) its equidistant H2NH∙∙∙HX (n = 2~8) with various electron acceptors (X = NH2, OH, Cl, CHO, CN, and NO2) using EOM-CCSD, time-dependent (TD) Hartree-Fock (HF) and various density functional theory (DFT) functionals, such as BLYP, B3LYP, long-range corrected (LC) DFT, and LC-DFT with an optimally tuned (OT) range separation parameter (µ) using Koopman's theorem to investigate the effect of the electron-withdrawing (or -donating) strength of end-capped functional group (X) and CT distance (R) on intra- and intermolecular CT excitation energies. As the electron-withdrawing strength of X increases, both intra- and intermolecular CT excitation energies tend to decrease, since energy gaps between orbitals corresponding to CT excitations (e.g., HOMO and LUMO) decrease. However, the effect of the electron-withdrawing group on intramolecular CT excitation energy is negligible (at most 0.5 eV). OT-LC-DFT shows accurate intermolecular CT excitation energy, but worse results in intramolecular CT excitation energy than LC-DFT with the default µ value (0.47). Therefore, we conclude that the optimal tuning method is not effective in predicting intramolecular CT excitation energy. While intermolecular CT excitation energy has excitonic binding energy with asymptotic behavior to CT distance that is not affected by the choice of range separation parameter, intramolecular CT excitation energy is affected by orbital relaxation energy, which strongly depends on the choice of range separation parameter, which makes the OT method of range separation parameter ineffective in predicting intramolecular CT excitation energy as well as local excitation with high accuracy.
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Affiliation(s)
- Han-Seok Bae
- Department of Chemistry Education, Daegu University, Gyeongsan-si 113-8656, Republic of Korea
| | - Dae-Hwan Ahn
- Department of Chemistry Education, Daegu University, Gyeongsan-si 113-8656, Republic of Korea
| | - Jong-Won Song
- Department of Chemistry Education, Daegu University, Gyeongsan-si 113-8656, Republic of Korea
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2
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Bhattacharya S, Li J, Yang W, Kanai Y. BSE@ GW Prediction of Charge Transfer Exciton in Molecular Complexes: Assessment of Self-Energy and Exchange-Correlation Dependence. J Phys Chem A 2024; 128:6072-6083. [PMID: 39011742 DOI: 10.1021/acs.jpca.4c02898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/17/2024]
Abstract
The Bethe-Salpeter equation using the GW approximation to the self-energy (BSE@GW) is a computationally attractive method for studying electronic excitation from first principles within the many-body Green's function theory framework. We examine its dependence on the underlying exchange-correlation (XC) approximation as well as on the GW approximation for predicting the charge transfer exciton formation at representative type-II interfaces between molecular systems of tetrachloro-1,2-benzoquinone (TCBQ) and acene derivatives. For the XC approximation, we consider several widely used generalized gradient approximation (GGA) and hybrid GGA functionals. For the GW self-energy approximation, we examine the recently proposed renormalized singles approach by Yang and coauthors [J. Phys. Chem. Lett. 2019, 10 (3), 447-452; J. Chem. Theory Comput. 2022, 18, 7570-7585] in addition to other commonly employed approximated GW schemes. We demonstrate a reliable prediction of the charge transfer exciton within the BSE@GW level of theory.
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Affiliation(s)
- Sampreeti Bhattacharya
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514, United States
| | - Jiachen Li
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Weitao Yang
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Yosuke Kanai
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514, United States
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514, United States
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3
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Vinod K, Jadhav SD, Hariharan M. Room Temperature Phosphorescence in Crystalline Iodinated Eumelanin Monomer. Chemistry 2024; 30:e202400499. [PMID: 38502668 DOI: 10.1002/chem.202400499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 03/01/2024] [Accepted: 03/19/2024] [Indexed: 03/21/2024]
Abstract
We report the room temperature phosphorescence upon iodination on a crystalline eumelanin monomer with shielded hydroxyl moieties, ethyl 5,6-dimethoxyindole-2-carboxylate (DMICE). Ultrafast intersystem crossing (ISC) is observed in the iodinated (IDMICE) as well as brominated (BDMICE) analogues of the eumelanin monomer derivative in solution. The triplet quantum yields (φT) and intersystem crossing rates (kISC) of the halogenated eumelanin derivatives areφ T B D M I C E ${{\phi{} }_{T}^{BDMICE}}$ =25.4±1.1 %;k I S C B D M I C E ${{k}_{ISC}^{BDMICE}}$ =1.95×109 s-1 andφ T I D M I C E ${{\phi{} }_{T}^{IDMICE}}$ =59.1±1.6 %;k I S C I D M I C E = ${{k}_{ISC}^{IDMICE}=}$ 1.36×1010 s-1, as monitored using transient absorption spectroscopy. Theoretical calculations based on nuclear ensemble method reveal that computed kISC and spin-orbit coupling matrix elements for eumelanin derivatives are larger for IDMICE relative to BDMICE. The halogen and π-π interactions, with distinct excitonic coupling and higher ISC rate promote phosphorescence in IDMICE molecular crystals. Accessing triplet excited states and resultant photoluminescence through structural modification of eumelanin scaffolds paves way for exploring the versatility of eumelanin-inspired molecules as bio-functional materials.
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Affiliation(s)
- Kavya Vinod
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Maruthamala P.O., Vithura, Thiruvananthapuram, 695551, Kerala, India
| | - Sohan D Jadhav
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Maruthamala P.O., Vithura, Thiruvananthapuram, 695551, Kerala, India
| | - Mahesh Hariharan
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Maruthamala P.O., Vithura, Thiruvananthapuram, 695551, Kerala, India
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4
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Liu S, Liu SS, Tang XM, Liu XY, Yang JJ, Cui G, Li L. Solvent effects on the photoinduced charge separation dynamics of directly linked zinc phthalocyanine-perylenediimide dyads: a nonadiabatic dynamics simulation with an optimally tuned screened range-separated hybrid functional. Phys Chem Chem Phys 2023; 25:28452-28464. [PMID: 37846460 DOI: 10.1039/d3cp03517d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2023]
Abstract
Herein, we have employed a combination of the optimally tuned screened range-separated hybrid (OT-SRSH) functional, the polarizable continuum model (PCM), and nonadiabatic dynamics (NAMD) simulations to investigate the photoinduced dynamics of directly linked donor-acceptor dyads formed using zinc phthalocyanine (ZnPc) and perylenediimide (PDI), in which ZnPc is the donor while PDI is the acceptor. Our simulations aim to analyze the behavior of these dyads upon local excitation of the ZnPc moiety in the gas phase and in benzonitrile. Our findings indicate that the presence of a solvent can significantly influence the excited state dynamics of ZnPc-PDI dyads. Specifically, the polar solvent benzonitrile effectively lowers the vertical excitation energies of the charge transfer (CT) state from ZnPc to PDI. As a result, the energetic order of the locally excited (LE) states of ZnPc and the CT states is reversed compared to the gas phase. Consequently, the photoinduced electron transfer (PET) dynamics from ZnPc to PDI, which is absent in the gas phase, takes place in benzonitrile with a time constant of 10.4 ps. Importantly, our present work not only qualitatively agrees with experimental results but also provides in-depth insights into the underlying mechanisms responsible for the photoinduced dynamics of ZnPc-PDI. Moreover, this study emphasizes the importance of appropriately considering solvent effects in NAMD simulation of organic donor-acceptor systems, taking into account the distinct excited state dynamics observed in the gas phase and benzonitrile. Furthermore, the combination of the OT-SRSH functional, the PCM solvent model, and nonadiabatic dynamics simulations shows promise as a strategy for investigating the complex excited state dynamics of organic donor-acceptor systems in solvents. These findings will be valuable for the future design of novel organic donor-acceptor structures with improved performance.
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Affiliation(s)
- Shuai Liu
- College of Chemistry and Material Science, Sichuan Normal University, Chengdu 610068, China.
| | - Sha-Sha Liu
- College of Chemistry and Material Science, Sichuan Normal University, Chengdu 610068, China.
| | - Xiao-Mei Tang
- College of Chemistry and Material Science, Sichuan Normal University, Chengdu 610068, China.
| | - Xiang-Yang Liu
- College of Chemistry and Material Science, Sichuan Normal University, Chengdu 610068, China.
| | - Jia-Jia Yang
- College of Chemistry and Material Science, Sichuan Normal University, Chengdu 610068, China.
| | - Ganglong Cui
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
- Hefei National Laboratory, Hefei 230088, China
| | - Laicai Li
- College of Chemistry and Material Science, Sichuan Normal University, Chengdu 610068, China.
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5
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Zhang CR, Yu HY, Zhang ML, Liu XM, Chen YH, Liu ZJ, Wu YZ, Chen HS. Modulating the organic photovoltaic properties of non-fullerene acceptors by molecular modification based on Y6: a theoretical study. Phys Chem Chem Phys 2023; 25:25465-25479. [PMID: 37712300 DOI: 10.1039/d3cp02520a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/16/2023]
Abstract
Developing non-fullerene acceptors (NFAs) by modifying the backbone, side chains and end groups is the most important strategy to improve the power conversion efficiency of organic solar cells (OSCs). Among numerous developed NFAs, Y6 and its derivatives are famous NFAs in the OSC field due to their good performance. Herein, in order to understand the mechanism of tuning the photovoltaic performance by modifying the Y6's center backbone, π-spacer and side-chains, we selected the PM6:Y6 OSC as a reference and systematically studied PM6:AQx-2, PM6:Y6-T, PM6:Y6-2T, PM6:Y6-O, PM6:Y6-1O and PM6:Y6-2O OSC systems based on extensive quantum chemistry calculations. The results indicate that introducing quinoxaline to substitute thiadiazole in the backbone induces a blue-shift of absorption spectra, reduces the charge transfer (CT) distance (Δd) and average electrostatic potential (ESP), and increases the singlet-triplet energy gap (ΔEST), CT excitation energy and the number of CT states in low-lying excitations. Inserting thienyl and dithiophenyl as π spacers generates a red-shift of absorption spectra, enlarges Δd and average ESP, and reduces ΔEST and the number of CT states. Introducing furo[3,2-b]furan for substituting one thieno[3,2-b]thiophene unit in the Y6's backbone causes a red-shift of absorption spectra and increases ΔEST, Δd and average ESP as well as CT excitation energy. Introducing alkoxyl as a side chain results in a blue-shift of absorption spectra, and increases ΔEST, Δd, average ESP, CT excitation energy and the number of CT states. The rate constants calculated using Marcus theory suggest that all the molecular modifications of Y6 reduce the exciton dissociation and charge recombination rates at the heterojunction interface, while introducing furo[3,2-b]furan and alkoxyl enlarges CT rates.
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Affiliation(s)
- Cai-Rong Zhang
- Department of Applied Physics, Lanzhou University of Technology, Lanzhou, Gansu 730050, China.
| | - Hai-Yuan Yu
- Department of Applied Physics, Lanzhou University of Technology, Lanzhou, Gansu 730050, China.
| | - Mei-Ling Zhang
- Department of Applied Physics, Lanzhou University of Technology, Lanzhou, Gansu 730050, China.
| | - Xiao-Meng Liu
- Department of Applied Physics, Lanzhou University of Technology, Lanzhou, Gansu 730050, China.
| | - Yu-Hong Chen
- Department of Applied Physics, Lanzhou University of Technology, Lanzhou, Gansu 730050, China.
| | - Zi-Jiang Liu
- School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou 730070, China
| | - You-Zhi Wu
- School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China
| | - Hong-Shan Chen
- College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou, Gansu 730070, China
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6
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Huynh H, Kelly TJ, Vu L, Hoang T, Nguyen PA, Le TC, Jarvis EA, Phan H. Quantum Chemistry-Machine Learning Approach for Predicting Properties of Lewis Acid-Lewis Base Adducts. ACS OMEGA 2023; 8:19119-19127. [PMID: 37273580 PMCID: PMC10233689 DOI: 10.1021/acsomega.3c02822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 05/09/2023] [Indexed: 06/06/2023]
Abstract
Synthetic design allowing predictive control of charge transfer and other optoelectronic properties of Lewis acid adducts remains elusive. This challenge must be addressed through complementary methods combining experimental with computational insights from first principles. Ab initio calculations for optoelectronic properties can be computationally expensive and less straightforward than those sufficient for simple ground-state properties, especially for adducts of large conjugated molecules and Lewis acids. In this contribution, we show that machine learning (ML) can accurately predict density functional theory (DFT)-calculated charge transfer and even properties associated with excited states of adducts from readily obtained molecular descriptors. Seven ML models, built from a dataset of over 1000 adducts, show exceptional performance in predicting charge transfer and other optoelectronic properties with a Pearson correlation coefficient of up to 0.99. More importantly, the influence of each molecular descriptor on predicted properties can be quantitatively evaluated from ML models. This contributes to the optimization of a priori design of Lewis adducts for future applications, especially in organic electronics.
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Affiliation(s)
- Hieu Huynh
- Fulbright
University Vietnam, Ho Chi
Minh 72908, Vietnam
| | - Thomas J. Kelly
- Loyola
Marymount University, Los Angeles, California 90045, United States
| | - Linh Vu
- Fulbright
University Vietnam, Ho Chi
Minh 72908, Vietnam
| | - Tung Hoang
- Independent
Researcher, Palo Alto, California 94303, Unites States
| | - Phuc An Nguyen
- Fulbright
University Vietnam, Ho Chi
Minh 72908, Vietnam
| | - Tu C. Le
- School
of Engineering, STEM College, RMIT University, Melbourne, Victoria 3000, Australia
| | - Emily A. Jarvis
- Loyola
Marymount University, Los Angeles, California 90045, United States
| | - Hung Phan
- Fulbright
University Vietnam, Ho Chi
Minh 72908, Vietnam
- Soka
University of America, Aliso Viejo, California 92656, United States
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7
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Bhat V, Callaway CP, Risko C. Computational Approaches for Organic Semiconductors: From Chemical and Physical Understanding to Predicting New Materials. Chem Rev 2023. [PMID: 37141497 DOI: 10.1021/acs.chemrev.2c00704] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
While a complete understanding of organic semiconductor (OSC) design principles remains elusive, computational methods─ranging from techniques based in classical and quantum mechanics to more recent data-enabled models─can complement experimental observations and provide deep physicochemical insights into OSC structure-processing-property relationships, offering new capabilities for in silico OSC discovery and design. In this Review, we trace the evolution of these computational methods and their application to OSCs, beginning with early quantum-chemical methods to investigate resonance in benzene and building to recent machine-learning (ML) techniques and their application to ever more sophisticated OSC scientific and engineering challenges. Along the way, we highlight the limitations of the methods and how sophisticated physical and mathematical frameworks have been created to overcome those limitations. We illustrate applications of these methods to a range of specific challenges in OSCs derived from π-conjugated polymers and molecules, including predicting charge-carrier transport, modeling chain conformations and bulk morphology, estimating thermomechanical properties, and describing phonons and thermal transport, to name a few. Through these examples, we demonstrate how advances in computational methods accelerate the deployment of OSCsin wide-ranging technologies, such as organic photovoltaics (OPVs), organic light-emitting diodes (OLEDs), organic thermoelectrics, organic batteries, and organic (bio)sensors. We conclude by providing an outlook for the future development of computational techniques to discover and assess the properties of high-performing OSCs with greater accuracy.
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Affiliation(s)
- Vinayak Bhat
- Department of Chemistry & Center for Applied Energy Research, University of Kentucky, Lexington, Kentucky 40506-0055, United States
| | - Connor P Callaway
- Department of Chemistry & Center for Applied Energy Research, University of Kentucky, Lexington, Kentucky 40506-0055, United States
| | - Chad Risko
- Department of Chemistry & Center for Applied Energy Research, University of Kentucky, Lexington, Kentucky 40506-0055, United States
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8
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Electronic and vibrational contributions to the reorganization energy of photosynthetic pigments. Chem Phys Lett 2023. [DOI: 10.1016/j.cplett.2023.140384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
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9
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Zhang T, Wang F, Kim HB, Choi IW, Wang C, Cho E, Konefal R, Puttisong Y, Terado K, Kobera L, Chen M, Yang M, Bai S, Yang B, Suo J, Yang SC, Liu X, Fu F, Yoshida H, Chen WM, Brus J, Coropceanu V, Hagfeldt A, Brédas JL, Fahlman M, Kim DS, Hu Z, Gao F. Ion-modulated radical doping of spiro-OMeTAD for more efficient and stable perovskite solar cells. Science 2022; 377:495-501. [PMID: 35901165 DOI: 10.1126/science.abo2757] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Record power conversion efficiencies (PCEs) of perovskite solar cells (PSCs) have been obtained with the organic hole transporter 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenyl-amine)9,9'-spirobifluorene (spiro-OMeTAD). Conventional doping of spiro-OMeTAD with hygroscopic lithium salts and volatile 4-tert-butylpyridine is a time-consuming process and also leads to poor device stability. We developed a new doping strategy for spiro-OMeTAD that avoids post-oxidation by using stable organic radicals as the dopant and ionic salts as the doping modulator (referred to as ion-modulated radical doping). We achieved PCEs of >25% and much-improved device stability under harsh conditions. The radicals provide hole polarons that instantly increase the conductivity and work function (WF), and ionic salts further modulate the WF by affecting the energetics of the hole polarons. This organic semiconductor doping strategy, which decouples conductivity and WF tunability, could inspire further optimization in other optoelectronic devices.
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Affiliation(s)
- Tiankai Zhang
- Department of Physics, Chemistry and Biology (IFM), Linköping University, 58183 Linköping, Sweden
| | - Feng Wang
- Department of Physics, Chemistry and Biology (IFM), Linköping University, 58183 Linköping, Sweden
| | - Hak-Beom Kim
- Korea Institute of Energy Research (KIER), Ulsan, Republic of Korea
| | - In-Woo Choi
- Korea Institute of Energy Research (KIER), Ulsan, Republic of Korea
| | - Chuanfei Wang
- Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, 60174 Norrköping, Sweden
| | - Eunkyung Cho
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Rafal Konefal
- Institute of Macromolecular Chemistry of the Czech Academy of Sciences, 162 06 Prague 6, Czech Republic
| | - Yuttapoom Puttisong
- Department of Physics, Chemistry and Biology (IFM), Linköping University, 58183 Linköping, Sweden
| | - Kosuke Terado
- Graduate School of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Libor Kobera
- Institute of Macromolecular Chemistry of the Czech Academy of Sciences, 162 06 Prague 6, Czech Republic
| | - Mengyun Chen
- Department of Physics, Chemistry and Biology (IFM), Linköping University, 58183 Linköping, Sweden
| | - Mei Yang
- Department of Physics, Chemistry and Biology (IFM), Linköping University, 58183 Linköping, Sweden
| | - Sai Bai
- Department of Physics, Chemistry and Biology (IFM), Linköping University, 58183 Linköping, Sweden
| | - Bowen Yang
- Laboratory of Photomolecular Science (LSPM), École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.,Department of Chemistry, Ångström Laboratory, Uppsala University, SE-751 20 Uppsala, Sweden
| | - Jiajia Suo
- Laboratory of Photomolecular Science (LSPM), École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.,Department of Chemistry, Ångström Laboratory, Uppsala University, SE-751 20 Uppsala, Sweden
| | - Shih-Chi Yang
- Laboratory for Thin Films and Photovoltaics, Empa-Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Duebendorf, Switzerland
| | - Xianjie Liu
- Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, 60174 Norrköping, Sweden
| | - Fan Fu
- Laboratory for Thin Films and Photovoltaics, Empa-Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Duebendorf, Switzerland
| | - Hiroyuki Yoshida
- Graduate School of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.,Molecular Chirality Research Center, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Weimin M Chen
- Department of Physics, Chemistry and Biology (IFM), Linköping University, 58183 Linköping, Sweden
| | - Jiri Brus
- Institute of Macromolecular Chemistry of the Czech Academy of Sciences, 162 06 Prague 6, Czech Republic
| | - Veaceslav Coropceanu
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Anders Hagfeldt
- Laboratory of Photomolecular Science (LSPM), École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.,Department of Chemistry, Ångström Laboratory, Uppsala University, SE-751 20 Uppsala, Sweden
| | - Jean-Luc Brédas
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Mats Fahlman
- Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, 60174 Norrköping, Sweden
| | - Dong Suk Kim
- Korea Institute of Energy Research (KIER), Ulsan, Republic of Korea
| | - Zhangjun Hu
- Department of Physics, Chemistry and Biology (IFM), Linköping University, 58183 Linköping, Sweden
| | - Feng Gao
- Department of Physics, Chemistry and Biology (IFM), Linköping University, 58183 Linköping, Sweden
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10
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Gould T, Dale SG. Poisoning density functional theory with benchmark sets of difficult systems. Phys Chem Chem Phys 2022; 24:6398-6403. [PMID: 35244641 DOI: 10.1039/d2cp00268j] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Large benchmark sets like GMTKN55 [Goerigk et al., Phys. Chem. Chem. Phys., 2017, 19, 32184] let us analyse the performance of density functional theory over a diverse range of systems and bonding types. However, assessing over a large and diverse set can miss cases where approaches fail badly, and can give a misleading sense of security. To this end we introduce a series of 'poison' benchmark sets, P30-5, P30-10 and P30-20, comprising systems with up to 5, 10 and 20 atoms, respectively. These sets represent the most difficult-to-model systems in GMTKN55. We expect them to be useful in developing new approximations, identifying weak points in existing ones, and to aid in selecting appropriate DFAs for computational studies involving difficult physics, e.g. catalysis.
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Affiliation(s)
- Tim Gould
- Qld Micro- and Nanotechnology Centre, Griffith University, Nathan, Qld 4111, Australia.
| | - Stephen G Dale
- Qld Micro- and Nanotechnology Centre, Griffith University, Nathan, Qld 4111, Australia.
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11
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Souza JPA, Benatto L, Candiotto G, Roman LS, Koehler M. Binding Energy of Triplet Excitons in Nonfullerene Acceptors: The Effects of Fluorination and Chlorination. J Phys Chem A 2022; 126:1393-1402. [PMID: 35192353 DOI: 10.1021/acs.jpca.1c10607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
One strategy to improve the photovoltaic properties of nonfullerene acceptors (NFAs), employed in state-of-art organic solar cells, is the rational fluorination or chlorination of these molecules. Although this modification improves important acceptor properties, little is known about the effects on the triplet states. Here, we combine the polarizable continuum model with an optimally tuned range-separated hybrid functional to investigate this issue. We find that fluorination or chlorination of NFAs decreases the degree of the highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) overlap along these molecules. Consequently, the energy gap between T1 and S1 states, ΔEST = ES1 - ET1, also decreases. This effect reduces the binding energy of triplet excitons, which favors their dissociation into free charges. Furthermore, the reduction of ΔEST can contribute to mitigating the losses produced by the nonradiative deactivation of the T1 excitons. Interestingly, although Cl has a lower electronegativity than F, chlorination is more effective to reduce ΔEST. Since the chlorination of NFAs is easier than fluorination, Cl substitution can be a useful approach to enhance solar energy harvesting using triplet excitons.
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Affiliation(s)
- J P A Souza
- Department of Physics, Federal University of Paraná, 81531-980 Curitiba, PR, Brazil
| | - L Benatto
- Department of Physics, Federal University of Paraná, 81531-980 Curitiba, PR, Brazil
| | - G Candiotto
- Institute of Chemistry, Federal University of Rio de Janeiro, 21941-909 Rio de Janeiro, RJ, Brazil
| | - L S Roman
- Department of Physics, Federal University of Paraná, 81531-980 Curitiba, PR, Brazil
| | - M Koehler
- Department of Physics, Federal University of Paraná, 81531-980 Curitiba, PR, Brazil
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12
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Song JW, Hirao K. Is charge-transfer excitation through a polyalkane single-bond chain an intramolecular charge-transfer?: EOM-CCSD and LC-BOP study. Chem Phys Lett 2022. [DOI: 10.1016/j.cplett.2022.139563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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13
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Madrid-Úsuga D, Ortiz A, Reina JH. Photophysical Properties of BODIPY Derivatives for the Implementation of Organic Solar Cells: A Computational Approach. ACS OMEGA 2022; 7:3963-3977. [PMID: 35155892 PMCID: PMC8829925 DOI: 10.1021/acsomega.1c04598] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 11/22/2021] [Indexed: 06/14/2023]
Abstract
Solar cells based on organic compounds are a proven emergent alternative to conventional electrical energy generation. Here, we provide a computational study of power conversion efficiency optimization of boron dipyrromethene (BODIPY) derivatives by means of their associated open-circuit voltage, short-circuit density, and fill factor. In doing so, we compute for the derivatives' geometrical structures, energy levels of frontier molecular orbitals, absorption spectra, light collection efficiencies, and exciton binding energies via density functional theory (DFT) and time-dependent (TD)-DFT calculations. We fully characterize four D-π-A (BODIPY) molecular systems of high efficiency and improved J sc that are well suited for integration into bulk heterojunction (BHJ) organic solar cells as electron-donor materials in the active layer. Our results are twofold: we found that molecular complexes with a structural isoxazoline ring exhibit a higher power conversion efficiency (PCE), a useful result for improving the BHJ current, and, on the other hand, by considering the molecular systems as electron-acceptor materials, with P3HT as the electron donor in the active layer, we found a high PCE compound favorability with a pyrrolidine ring in its structure, in contrast to the molecular systems built with an isoxazoline ring. The theoretical characterization of the electronic properties of the BODIPY derivatives provided here, computed with a combination of ab initio methods and quantum models, can be readily applied to other sets of molecular complexes to hierarchize optimal power conversion efficiency.
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Affiliation(s)
- Duvalier Madrid-Úsuga
- Centre
for Bioinformatics and Photonics—CIBioFi, Universidad del Valle, Calle 13 No. 100-00, Edificio E20 No. 1069, 760032 Cali, Colombia
- Quantum
Technologies, Information and Complexity Group—QuanTIC, Departamento
de Física, Universidad del Valle, 760032 Cali, Colombia
| | - Alejandro Ortiz
- Centre
for Bioinformatics and Photonics—CIBioFi, Universidad del Valle, Calle 13 No. 100-00, Edificio E20 No. 1069, 760032 Cali, Colombia
- Heterocyclic
Compounds Research Group—GICH, Departamento de Química, Universidad del Valle, 760032 Cali, Colombia
| | - John H. Reina
- Centre
for Bioinformatics and Photonics—CIBioFi, Universidad del Valle, Calle 13 No. 100-00, Edificio E20 No. 1069, 760032 Cali, Colombia
- Quantum
Technologies, Information and Complexity Group—QuanTIC, Departamento
de Física, Universidad del Valle, 760032 Cali, Colombia
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14
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Hemmingsen LO, Hervir OAJ, Dale SG. Linear fractional charge behavior in density functional theory through dielectric tuning of conductor-like polarizable continuum model. J Chem Phys 2022; 156:014106. [PMID: 34998325 DOI: 10.1063/5.0067685] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
A property of exact density functional theory is linear fractional charge behavior as electrons are added or removed from a molecule. Typical density functional approximations (DFAs) exhibit delocalization error, which overstabilizes this fractional charge. Conversely, solvent corrections have been shown to erroneously destabilize this fractional charge. This work will show that an implicit solvent correction with a tuned dielectric can be used as an ad hoc correction to offset the delocalizing character of DFAs and achieve linear fractional charge behavior. While desirable, in principle, we find that this linear charge behavior degrades the vertical ionization energies reported by DFAs. Our results reveal that the localizing character of the solvent correction and the Hartree-Fock (HF) exchange offset each other. This helps explain the decreased ratios of HF exchange to DFA exchange in long-range hybrid tuning studies that use a solvent correction.
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Affiliation(s)
- Luke O Hemmingsen
- Research School of Chemistry, Australian National University, Acton 2601, Australia
| | - Oliver A J Hervir
- Research School of Chemistry, Australian National University, Acton 2601, Australia
| | - Stephen G Dale
- Queensland Micro- and Nanotechnology Centre, Griffith University, Nathan 4111, Australia
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15
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Yu HY, Zhang CR, Zhang ML, Liu XM, Gong JJ, Liu ZJ, Wu YZ, Chen HS. Molecular tuning of non-fullerene electron acceptors in organic photovoltaics: a theoretical study. NEW J CHEM 2022. [DOI: 10.1039/d2nj03608h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
On the basis of the famous A–D–A-type non-fullerene acceptor IT-4F, this work investigates the effects of introducing methyl groups and substituting dicyano with O on optoelectronic properties and photovoltaic performances.
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Affiliation(s)
- Hai-Yuan Yu
- Department of Applied Physics, Lanzhou University of Technology, Lanzhou, Gansu 730050, China
| | - Cai-Rong Zhang
- Department of Applied Physics, Lanzhou University of Technology, Lanzhou, Gansu 730050, China
| | - Mei-Ling Zhang
- Department of Applied Physics, Lanzhou University of Technology, Lanzhou, Gansu 730050, China
| | - Xiao-Meng Liu
- Department of Applied Physics, Lanzhou University of Technology, Lanzhou, Gansu 730050, China
| | - Ji-Jun Gong
- Department of Applied Physics, Lanzhou University of Technology, Lanzhou, Gansu 730050, China
| | - Zi-Jiang Liu
- School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou 730070, China
| | - You-Zhi Wu
- School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China
| | - Hong-Shan Chen
- College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou, Gansu, 730070, China
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16
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A comparative study of PffBT4T-2OD/EH-IDTBR and PffBT4T-2OD/PC71BM organic photovoltaic heterojunctions. J Photochem Photobiol A Chem 2021. [DOI: 10.1016/j.jphotochem.2021.113225] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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17
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Leng C, You S, Si Y, Qin HM, Liu J, Huang WQ, Li K. Unraveling the Mechanism of Near-Infrared Thermally Activated Delayed Fluorescence of TPA-Based Molecules: Effect of Hydrogen Bond Steric Hindrance. J Phys Chem A 2021; 125:2905-2912. [PMID: 33822612 DOI: 10.1021/acs.jpca.1c00739] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A recently synthesized novel molecule (named CAT-1) exhibits intriguing near-infrared (NIR) thermally activated delayed fluorescence (TADF) close to 1000 nm wavelength; however, the mechanism behind these intrinsic properties is not fully understood. Herein, we unravel that the fluorescence emission spectrum with a broad wavelength range (770-950 nm) of CAT-1 is primarily induced by hydrogen bond steric hindrance based on density functional theory and Marcus theory. It is found that the hydrogen bond steric hindrance plays a critical role in inhibiting the twist of the configuration of different excited states, which leads to the minor driving force for fast electron trapping between the excited states, as well as small internal reorganization energy caused by less changed geometric configuration. Furthermore, such steric hindrance will cause a more distorted plane, resulting in a less favorable electron delocalization. A faster reverse intersystem crossing (RISC) rate is then obtained due to the nearly unchanged conformation between excited states caused by steric hindrance, although the spin-orbit coupling is small. Consequently, the NIR TADF with a longer wavelength can be emitted in CAT-1. This work shows that the hydrogen bond steric hindrance can fine-tune the electronic interactions of the donor and acceptor units to control the TADF.
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Affiliation(s)
- Can Leng
- Science and Technology on Parallel and Distributed Processing Laboratory, National University of Defense Technology, Changsha 410073, China.,Laboratory of Software Engineering for Complex Systems, National University of Defense Technology, Changsha 410073, China.,National Supercomputer Center in Changsha, Changsha 410082, China
| | - Sheng You
- National Supercomputer Center in Changsha, Changsha 410082, China
| | - Yubing Si
- College of Chemistry, Zhengzhou University, Zhengzhou 450001, China
| | - Hai-Mei Qin
- College of Chemistry and Chemical Engineering, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, Xiamen University, Xiamen 361005, China
| | - Jie Liu
- Science and Technology on Parallel and Distributed Processing Laboratory, National University of Defense Technology, Changsha 410073, China.,Laboratory of Software Engineering for Complex Systems, National University of Defense Technology, Changsha 410073, China
| | - Wei-Qing Huang
- Department of Applied Physics, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Keqin Li
- College of Computer Science and Electronic Engineering, Hunan University, Changsha 410082, China.,Department of Computer Science, State University of New York, New Paltz, New York 12561, United States
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18
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Fujita T, Noguchi Y, Hoshi T. Revisiting the Charge-Transfer States at Pentacene/C 60 Interfaces with the GW/Bethe-Salpeter Equation Approach. MATERIALS (BASEL, SWITZERLAND) 2020; 13:E2728. [PMID: 32560127 PMCID: PMC7345661 DOI: 10.3390/ma13122728] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 06/11/2020] [Accepted: 06/13/2020] [Indexed: 11/16/2022]
Abstract
Molecular orientations and interfacial morphologies have critical effects on the electronic states of donor/acceptor interfaces and thus on the performance of organic photovoltaic devices. In this study, we explore the energy levels and charge-transfer states at the organic donor/acceptor interfaces on the basis of the fragment-based GW and Bethe-Salpeter equation approach. The face-on and edge-on orientations of pentacene/C60 bilayer heterojunctions have employed as model systems. GW+Bethe-Salpeter equation calculations were performed for the local interface structures in the face-on and edge-on bilayer heterojunctions, which contain approximately 2000 atoms. Calculated energy levels and charge-transfer state absorption spectra are in reasonable agreements with those obtained from experimental measurements. We found that the dependence of the energy levels on interfacial morphology is predominantly determined by the electrostatic contribution of polarization energy, while the effects of induction contribution in the edge-on interface are similar to those in the face-on. Moreover, the delocalized charge-transfer states contribute to the main absorption peak in the edge-on interface, while the face-on interface features relatively localized charge-transfer states in the main absorption peak. The impact of the interfacial morphologies on the polarization and charge delocalization effects is analyzed in detail.
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Affiliation(s)
| | - Yoshifumi Noguchi
- Department of Applied Chemistry and Biochemical Engineering, Graduate School of Engineering, Shizuoka University, Hamamatsu, Shizuoka 432-8561, Japan;
| | - Takeo Hoshi
- Department of Applied Mathematics and Physics, Tottori University, Tottori 680-8550, Japan;
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19
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Sousa KRDA, Benatto L, Wouk L, Roman LS, Koehler M. Effects of non-halogenated solvent on the main properties of a solution-processed polymeric thin film for photovoltaic applications: a computational study. Phys Chem Chem Phys 2020; 22:9693-9702. [PMID: 32329493 DOI: 10.1039/d0cp01303j] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Organic photovoltaic (OPV) devices have reached high power conversion efficiencies, but they are usually processed using halogenated toxic solvents. Hence, before OPV devices can be mass-produced by industrial processing, it would be desirable to replace those solvents with eco-friendly ones. Theoretical tools may be then a powerful ally in the search for those new solvents. In order to better understand the mechanisms behind the interaction between solvent and polymer, classical molecular dynamics (MD) calculations were used to produce a thin film of poly(4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl) (PTB7-Th), processed using two different solvents. PTB7-Th is widely applied as a donor material in OPVs. The first solvent is ortho-dichlorobenzene (o-DCB), which is a highly toxic solvent widely used in lab-scale studies. The second solvent is ortho-methylanisole (o-MA), which is an eco-friendly solvent for organic photovoltaic (OPV) manufacturing. Here we use a solvent evaporation protocol to simulate the formation of the PTB7-Th film. We demonstrate that our theoretical MD calculations were able to capture some differences in the macroscopic properties of thin films formed by o-DCB or o-MA evaporation. We found that the interaction of the halogenated solvent with the polymer tends to break the bonds between the lateral thiophenediyl groups and the main chain. We show that those defects may create traps that can affect the charge transport and also can be responsible for a blue shift in the absorption spectrum. Using the Monte Carlo method, we also verified the influence of the resulting MD morphology on the mobility of holes. Our theoretical results showed good agreement with the experimental measurements and both demonstrate that o-MA can be used to make polymer thin films without any loss of key properties for the device performance. The findings here highlight the importance of theoretical results as a guide to the morphological optimization of green processed polymeric films.
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20
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Cho E, Coropceanu V, Brédas JL. Electronic Structure of Multicomponent Organic Molecular Materials: Evaluation of Range-Separated Hybrid Functionals. J Chem Theory Comput 2020; 16:3712-3719. [DOI: 10.1021/acs.jctc.0c00138] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Eunkyung Cho
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721-0088, United States
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Veaceslav Coropceanu
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721-0088, United States
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Jean-Luc Brédas
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721-0088, United States
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
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21
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Ma X, Yi Y. Electronic polarization in dipolar organic molecular semiconductors: The case study of 1,2,3,4-tetrafluoro-6,7-dimethylnaphthalene crystal. CHINESE CHEM LETT 2020. [DOI: 10.1016/j.cclet.2019.05.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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22
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Han G, Yi Y. Local Excitation/Charge-Transfer Hybridization Simultaneously Promotes Charge Generation and Reduces Nonradiative Voltage Loss in Nonfullerene Organic Solar Cells. J Phys Chem Lett 2019; 10:2911-2918. [PMID: 31088080 DOI: 10.1021/acs.jpclett.9b00928] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
High power conversion efficiencies in state-of-the-art nonfullerene organic solar cells (NF OSCs) call for elucidation of the underlying working mechanisms of both high photocurrent densities and low nonradiative voltage losses under small energy offsets. Here, to address this fundamental issue, we have assessed the nature of interfacial charge-transfer (CT) states in a representative small-molecule NF OSC (DRTB-T:IT-4F) by time-dependent density functional theory calculations. The calculated results point to the fact that the CT states can borrow considerable oscillator strengths from the energy-close local excitation (LE) states or be fully hybridized with these LE states by molecular aggregation at the donor-acceptor interfaces. The LE/CT hybridization can promote charge generation by direct population of thermalized CT or LE/CT states under illumination. At the same time, the increased oscillator strengths of the lowest CT state will improve the luminescence quantum efficiencies and thus reduce nonradiative voltage losses. Our work suggests that it is crucial to tune the LE/CT hybridization by optimization of the donor and acceptor molecular and interfacial structures to further improve the NF OSC performance.
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Affiliation(s)
- Guangchao Han
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, CAS Research/Education Center for Excellence in Molecular Sciences , Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190 , China
| | - Yuanping Yi
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, CAS Research/Education Center for Excellence in Molecular Sciences , Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190 , China
- University of Chinese Academy Sciences , Beijing 100049 , China
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23
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Han G, Yi Y. Origin of Photocurrent and Voltage Losses in Organic Solar Cells. ADVANCED THEORY AND SIMULATIONS 2019. [DOI: 10.1002/adts.201900067] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Guangchao Han
- Beijing National Laboratory for Molecular SciencesCAS Key Laboratory of Organic SolidsCAS Research/Education Center for Excellence in Molecular SciencesInstitute of ChemistryChinese Academy of Sciences Beijing 100190 China
- University of Chinese Academy Sciences Beijing 100049 China
| | - Yuanping Yi
- Beijing National Laboratory for Molecular SciencesCAS Key Laboratory of Organic SolidsCAS Research/Education Center for Excellence in Molecular SciencesInstitute of ChemistryChinese Academy of Sciences Beijing 100190 China
- University of Chinese Academy Sciences Beijing 100049 China
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24
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San-Fabián E, Louis E, Díaz-García MA, Chiappe G, Vergés JA. Transport and Optical Gaps in Amorphous Organic Molecular Materials. Molecules 2019; 24:E609. [PMID: 30744125 PMCID: PMC6384593 DOI: 10.3390/molecules24030609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 02/01/2019] [Accepted: 02/07/2019] [Indexed: 11/16/2022] Open
Abstract
The standard procedure to identify the hole- or electron-acceptor character of amorphous organic materials used in OLEDs is to look at the values of a pair of basic parameters, namely, the ionization potential (IP) and the electron affinity (EA). Recently, using published experimental data, the present authors showed that only IP matters, i.e., materials with IP > 5.7 (<5.7) showing electron (hole) acceptor character. Only three materials fail to obey this rule. This work reports ab initio calculations of IP and EA of those materials plus two materials that behave according to that rule, following a route which describes the organic material by means of a single molecule embedded in a polarizable continuum medium (PCM) characterized by a dielectric constant ε . PCM allows to approximately describe the extended character of the system. This "compound" system was treated within density functional theory (DFT) using several combinations of the functional/basis set. In the preset work ε was derived by assuming Koopmans' theorem to hold. Optimal ε values are in the range 4.4⁻5.0, close to what is expected for this material family. It was assumed that the optical gap corresponds to the excited state with a large oscillator strength among those with the lowest energies, calculated with time-dependent DFT. Calculated exciton energies were in the range 0.76⁻1.06 eV, and optical gaps varied from 3.37 up to 4.50 eV. The results are compared with experimental data.
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Affiliation(s)
- Emilio San-Fabián
- Departamento de Química Física, Universidad de Alicante, 03080 Alicante, Spain.
| | - Enrique Louis
- Departamento de Física Aplicada, Universidad de Alicante, 03080 Alicante, Spain.
| | - María A Díaz-García
- Departamento de Física Aplicada, Universidad de Alicante, 03080 Alicante, Spain.
| | - Guillermo Chiappe
- Departamento de Física Aplicada, Universidad de Alicante, 03080 Alicante, Spain.
| | - José A Vergés
- Departamento de Teoría y Simulación de Materiales, Instituto de Ciencia de Materiales de Madrid (CSIC), Cantoblanco, 28049 Madrid, Spain;.
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25
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Muchová E, Slavíček P. Beyond Koopmans' theorem: electron binding energies in disordered materials. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:043001. [PMID: 30524069 DOI: 10.1088/1361-648x/aaf130] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The topical review focuses on calculating ionization energies (IE), or electronic polarons in quasi-particle terminology, in large disordered systems, e.g. for a solute dissolved in a molecular solvent. The simplest estimate of the ionization energy is provided by one-electron energies in the Hartree-Fock theory, but the calculated quantities are not accurate. Density functional theory as many-body theory provides a principal opportunity for calculating one-electron energies including correlation and relaxation effects, i.e. the true energies of electronic polarons. We argue that such a principal possibility materializes within the concept of optimally tuned range-separated hybrid functionals (OT-RSH). We describe various schemes for optimal tuning. Importantly, the OT-RSH scheme is investigated for systems capped with dielectric continuum, providing a consistent picture on the QM/dielectric boundary. Finally, some limitations and open issues of the OT-RSH approach are addressed.
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Affiliation(s)
- Eva Muchová
- Department of Physical Chemistry, University of Chemistry and Technology, Prague, Czech Republic
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26
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Lin Z, Van Voorhis T. Triplet Tuning: A Novel Family of Non-Empirical Exchange–Correlation Functionals. J Chem Theory Comput 2019; 15:1226-1241. [DOI: 10.1021/acs.jctc.8b00853] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Zhou Lin
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Troy Van Voorhis
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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27
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Kastinen T, da Silva Filho DA, Paunonen L, Linares M, Ribeiro Junior LA, Cramariuc O, Hukka TI. Electronic couplings and rates of excited state charge transfer processes at poly(thiophene-co-quinoxaline)–PC71BM interfaces: two- versus multi-state treatments. Phys Chem Chem Phys 2019; 21:25606-25625. [DOI: 10.1039/c9cp04837e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Multi-state effects should be considered when calculating electronic couplings at local polymer–fullerene interfaces with the non-tuned and optimally tuned long-range corrected functionals.
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Affiliation(s)
- Tuuva Kastinen
- Chemistry and Advanced Materials
- Faculty of Engineering and Natural Sciences
- Tampere University
- FI-33014 Tampere University
- Finland
| | | | - Lassi Paunonen
- Mathematics
- Faculty of Information Technology and Communication Sciences
- Tampere University
- FI-33014 Tampere University
- Finland
| | - Mathieu Linares
- Laboratory of Organic Electronics
- ITN
- Campus Norrköping
- Linköping University
- SE-581 83 Linköping
| | | | - Oana Cramariuc
- Physics
- Faculty of Engineering and Natural Sciences
- Tampere University
- FI-33014 Tampere University
- Finland
| | - Terttu I. Hukka
- Chemistry and Advanced Materials
- Faculty of Engineering and Natural Sciences
- Tampere University
- FI-33014 Tampere University
- Finland
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28
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Fujita T, Alam MK, Hoshi T. Thousand-atom ab initio calculations of excited states at organic/organic interfaces: toward first-principles investigations of charge photogeneration. Phys Chem Chem Phys 2018; 20:26443-26452. [PMID: 30306163 DOI: 10.1039/c8cp05574b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Predicting electronically excited states across electron-donor/electron acceptor interfaces is essential for understanding the charge photogeneration process in organic solar cells. However, organic solar cells are large and disordered systems, and their excited states cannot be easily accessed by conventional quantum chemistry approaches. Moreover, a large number of excited states must be obtained to fully understand the charge separation mechanism. Recently, we have developed a novel fragment-based excited state method which can efficiently calculate a large number of states in molecular aggregates. In this article, we demonstrate the large-scale excited-state calculations by investigating interfacial charge transfer (ICT) states across the electron-donor/electron acceptor interfaces. As the model systems, we considered the face-on and edge-on configurations of pentacene/C60 bilayer heterojunction structures. These model structures contain approximately 1.8 × 105 atoms, and their local interface regions containing 2000 atoms were treated quantum mechanically, embedded in the electrostatic potentials from the remaining parts. Therefore, the charge delocalization effect, structural disorder, and the resulting heterogeneous electrostatic and polarizable environments were taken into account in the excited-state calculations. The computed energies of the low-lying ICT states are in reasonable agreement with experimental estimates. By comparing the edge-on and face-on configurations of the pentacene/C60 interfaces, we discuss the influence of interfacial morphologies on the energetics and charge delocalization of ICT states. In addition, we present the detailed characterization of excited states and highlight the importance of hybridization effects between pentacene excited states and ICT states. The large-scale ab initio calculations for the interface systems enabled the exploration of the ICT states, leading to first-principles investigation of the charge separation mechanism in organic solar cells.
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Affiliation(s)
- Takatoshi Fujita
- Institute for Molecular Science, Okazaki, Aichi 444-0865, Japan.
| | - Md Khorshed Alam
- Department of Physics, University of Barisal, Barisal-8200, Bangladesh
| | - Takeo Hoshi
- Department of Applied Mathmatics and Physics, Tottori University, Tottori 680-8550, Japan
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29
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Kronik L, Kümmel S. Dielectric Screening Meets Optimally Tuned Density Functionals. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1706560. [PMID: 29665112 DOI: 10.1002/adma.201706560] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 12/19/2017] [Indexed: 06/08/2023]
Abstract
A short overview of recent attempts at merging two independently developed methods is presented. These are the optimal tuning of a range-separated hybrid (OT-RSH) functional, developed to provide an accurate first-principles description of the electronic structure and optical properties of gas-phase molecules, and the polarizable continuum model (PCM), developed to provide an approximate but computationally tractable description of a solvent in terms of an effective dielectric medium. After a brief overview of the OT-RSH approach, its combination with the PCM as a potentially accurate yet low-cost approach to the study of molecular assemblies and solids, particularly in the context of photocatalysis and photovoltaics, is discussed. First, solvated molecules are considered, with an emphasis on the challenge of balancing eigenvalue and total energy trends. Then, it is shown that the same merging of methods can also be used to study the electronic and optical properties of molecular solids, with a similar discussion of the pros and cons. Tuning of the effective scalar dielectric constant as one recent approach that mitigates some of the difficulties in merging the two approaches is considered.
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Affiliation(s)
- Leeor Kronik
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovoth, 76100, Israel
| | - Stephan Kümmel
- Theoretical Physics IV, Universität Bayreuth, 95440, Bayreuth, Germany
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30
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Yang X, Wang W, Yin S. Theoretical estimation of the dissociation energy of CT states at the acenes/C60 interfaces using fragmental-based ALMO method. COMPUT THEOR CHEM 2018. [DOI: 10.1016/j.comptc.2018.07.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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31
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Madkour LH, Kaya S, Guo L, Kaya C. Quantum chemical calculations, molecular dynamic (MD) simulations and experimental studies of using some azo dyes as corrosion inhibitors for iron. Part 2: Bis–azo dye derivatives. J Mol Struct 2018. [DOI: 10.1016/j.molstruc.2018.03.013] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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32
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Madkour LH, Kaya S, Obot IB. Computational, Monte Carlo simulation and experimental studies of some arylazotriazoles (AATR) and their copper complexes in corrosion inhibition process. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.01.055] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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33
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Joo B, Han H, Kim EG. Solvation-Mediated Tuning of the Range-Separated Hybrid Functional: Self-Sufficiency through Screened Exchange. J Chem Theory Comput 2018; 14:2823-2828. [DOI: 10.1021/acs.jctc.8b00049] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bora Joo
- Department of Polymer Science and Engineering, Dankook University, Yongin, Gyeonggi 16890, Korea
| | - Herim Han
- Department of Polymer Science and Engineering, Dankook University, Yongin, Gyeonggi 16890, Korea
| | - Eung-Gun Kim
- Department of Polymer Science and Engineering, Dankook University, Yongin, Gyeonggi 16890, Korea
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Wong ZC, Fan WY, Chwee TS, Sullivan MB. Using non-empirically tuned range-separated functionals with simulated emission bands to model fluorescence lifetimes. Phys Chem Chem Phys 2018; 19:21046-21057. [PMID: 28748247 DOI: 10.1039/c7cp03418k] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fluorescence lifetimes were evaluated using TD-DFT under different approximations for the emitting molecule and various exchange-correlation functionals, such as B3LYP, BMK, CAM-B3LYP, LC-BLYP, M06, M06-2X, M11, PBE0, ωB97, ωB97X, LC-BLYP*, and ωB97X* where the range-separation parameters in the last two functionals were tuned in a non-empirical fashion. Changes in the optimised molecular geometries between the ground and electronically excited states were found to affect the quality of the calculated lifetimes significantly, while the inclusion of vibronic features led to further improvements over the assumption of a vertical electronic transition. The LC-BLYP* functional was found to return the most accurate fluorescence lifetimes with unsigned errors that are mostly within 1.5 ns of experimental values.
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Affiliation(s)
- Z C Wong
- Institute of High Performance Computing, Agency for Science, Technology and Research (A*STAR), 1 Fusionopolis Way, 138632, Singapore. and NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 28 Medical Drive, 117456, Singapore
| | - W Y Fan
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore
| | - T S Chwee
- Institute of High Performance Computing, Agency for Science, Technology and Research (A*STAR), 1 Fusionopolis Way, 138632, Singapore.
| | - Michael B Sullivan
- Institute of High Performance Computing, Agency for Science, Technology and Research (A*STAR), 1 Fusionopolis Way, 138632, Singapore. and Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore
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35
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Rinn A, Breuer T, Wiegand J, Beck M, Hübner J, Döring RC, Oestreich M, Heimbrodt W, Witte G, Chatterjee S. Interfacial Molecular Packing Determines Exciton Dynamics in Molecular Heterostructures: The Case of Pentacene-Perfluoropentacene. ACS APPLIED MATERIALS & INTERFACES 2017; 9:42020-42028. [PMID: 29135216 DOI: 10.1021/acsami.7b11118] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The great majority of electronic and optoelectronic devices depend on interfaces between p-type and n-type semiconductors. Finding matching donor-acceptor systems in molecular semiconductors remains a challenging endeavor because structurally compatible molecules may not necessarily be suitable with respect to their optical and electronic properties, and the large exciton binding energy in these materials may favor bound electron-hole pairs rather than free carriers or charge transfer at an interface. Regardless, interfacial charge-transfer exciton states are commonly considered as an intermediate step to achieve exciton dissociation. The formation efficiency and decay dynamics of such states will strongly depend on the molecular makeup of the interface, especially the relative alignment of donor and acceptor molecules. Structurally well-defined pentacene-perfluoropentacene heterostructures of different molecular orientations are virtually ideal model systems to study the interrelation between molecular packing motifs at the interface and their electronic properties. Comparing the emission dynamics of the heterosystems and the corresponding unitary films enables accurate assignment of every observable emission signal in the heterosystems. These heterosystems feature two characteristic interface-specific luminescence channels at around 1.4 and 1.5 eV that are not observed in the unitary samples. Their emission strength strongly depends on the molecular alignment of the respective donor and acceptor molecules, emphasizing the importance of structural control for device construction.
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Affiliation(s)
- Andre Rinn
- Faculty of Physics & Materials Sciences Centre, Philipps-Universität Marburg , Renthof 5, 35032 Marburg, Germany
| | - Tobias Breuer
- Faculty of Physics & Materials Sciences Centre, Philipps-Universität Marburg , Renthof 5, 35032 Marburg, Germany
| | - Julia Wiegand
- Institut für Festkörperphysik, Leibniz Universität Hannover , Appelstrasse 2, D-30167 Hannover, Germany
| | - Michael Beck
- Institut für Festkörperphysik, Leibniz Universität Hannover , Appelstrasse 2, D-30167 Hannover, Germany
| | - Jens Hübner
- Institut für Festkörperphysik, Leibniz Universität Hannover , Appelstrasse 2, D-30167 Hannover, Germany
| | - Robin C Döring
- Faculty of Physics & Materials Sciences Centre, Philipps-Universität Marburg , Renthof 5, 35032 Marburg, Germany
| | - Michael Oestreich
- Institut für Festkörperphysik, Leibniz Universität Hannover , Appelstrasse 2, D-30167 Hannover, Germany
| | - Wolfram Heimbrodt
- Faculty of Physics & Materials Sciences Centre, Philipps-Universität Marburg , Renthof 5, 35032 Marburg, Germany
| | - Gregor Witte
- Faculty of Physics & Materials Sciences Centre, Philipps-Universität Marburg , Renthof 5, 35032 Marburg, Germany
| | - Sangam Chatterjee
- Faculty of Physics & Materials Sciences Centre, Philipps-Universität Marburg , Renthof 5, 35032 Marburg, Germany
- Institute of Experimental Physics I, Justus-Liebig-University Giessen , Heinrich-Buff-Ring 16, D-35392 Giessen, Germany
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36
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Fazzi D, Barbatti M, Thiel W. Hot and Cold Charge-Transfer Mechanisms in Organic Photovoltaics: Insights into the Excited States of Donor/Acceptor Interfaces. J Phys Chem Lett 2017; 8:4727-4734. [PMID: 28903560 DOI: 10.1021/acs.jpclett.7b02144] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The evolution of the excited-state manifold in organic D/A aggregates (e.g., the prototypical P3HT/PCBM) is investigated through a bottom-up approach via first-principles calculations. We show how the excited-state energies, the charge transfer (CT) states, and the electron-hole density distributions are strongly influenced by the size, the orientation, and the position (i.e., on-top versus on-edge phases) of P3HT/PCBM domains. We discuss how the structural order influences the excited-state electronic structure, providing an atomistic interpretation of the photophysics of organic blends. We show how the simultaneous presence of on-top and on-edge phases does not alter the optical absorption spectrum of the blend but does affect the photophysics. Photovoltaic processes such as (i) the simultaneous charge generation obtained from hot and cold excitations, (ii) the instantaneous and delayed charge separation, and (iii) the pump-push-probe charge generation can be interpreted based on our study.
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Affiliation(s)
- Daniele Fazzi
- Max-Planck-Institut für Kohlenforschung , Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany
| | | | - Walter Thiel
- Max-Planck-Institut für Kohlenforschung , Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany
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37
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Zheng Z, Egger DA, Brédas JL, Kronik L, Coropceanu V. Effect of Solid-State Polarization on Charge-Transfer Excitations and Transport Levels at Organic Interfaces from a Screened Range-Separated Hybrid Functional. J Phys Chem Lett 2017; 8:3277-3283. [PMID: 28666085 DOI: 10.1021/acs.jpclett.7b01276] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We develop a robust approach for the description of the energetics of charge-transfer (CT) excitations and transport levels at organic interfaces based on a screened range-separated hybrid (SRSH) functional. We find that SRSH functionals correctly capture the effect of solid-state electronic polarization on transport gap renormalization and on screening of the electrostatic electron-hole interaction. With respect to calculations based on nonscreened optimally tuned RSH (long-range corrected) functionals, the SRSH-based calculations can be performed for both isolated molecular complexes and systems embedded in a dielectric medium with the same range-separation parameter, which allows a clear physical interpretation of the results in terms of solid-state polarization without any perturbation of the molecular electronic structure. By considering weakly interacting donor/acceptor complexes of pentacene with C60 and poly-3-hexylthiophene (P3HT) with PCBM, we show that this new approach provides CT-state energies that compare very well with experimental data.
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Affiliation(s)
- Zilong Zheng
- School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology , Atlanta, Georgia 30332-0400, United States
| | - David A Egger
- Department of Materials and Interfaces, Weizmann Institute of Science , Rehovoth 76100, Israel
| | - Jean-Luc Brédas
- School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology , Atlanta, Georgia 30332-0400, United States
| | - Leeor Kronik
- Department of Materials and Interfaces, Weizmann Institute of Science , Rehovoth 76100, Israel
| | - Veaceslav Coropceanu
- School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology , Atlanta, Georgia 30332-0400, United States
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38
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Zheng Z, Tummala NR, Fu YT, Coropceanu V, Brédas JL. Charge-Transfer States in Organic Solar Cells: Understanding the Impact of Polarization, Delocalization, and Disorder. ACS APPLIED MATERIALS & INTERFACES 2017; 9:18095-18102. [PMID: 28481497 DOI: 10.1021/acsami.7b02193] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
We investigate the impact of electronic polarization, charge delocalization, and energetic disorder on the charge-transfer (CT) states formed at a planar C60/pentacene interface. The ability to examine large complexes containing up to seven pentacene molecules and three C60 molecules allows us to take explicitly into account the electronic polarization effects. These complexes are extracted from a bilayer architecture modeled by molecular dynamics simulations and evaluated by means of electronic-structure calculations based on long-range-separated functionals (ωB97XD and BNL) with optimized range-separation parameters. The energies of the lowest charge-transfer states derived for the large complexes are in very good agreement with the experimentally reported values. The average singlet-triplet energy splittings of the lowest CT states are calculated not to exceed 10 meV. The rates of geminate recombination as well as of dissociation of the triplet excitons are also evaluated. In line with experiment, our results indicate that the pentacene triplet excitons generated through singlet fission can dissociate into separated charges on a picosecond time scale, despite the fact that their energy in C60/pentacene heterojunctions is slightly lower than the energies of the lowest CT triplet states.
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Affiliation(s)
- Zilong Zheng
- School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology , Atlanta, Georgia 30332-0400, United States
| | - Naga Rajesh Tummala
- School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology , Atlanta, Georgia 30332-0400, United States
| | - Yao-Tsung Fu
- School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology , Atlanta, Georgia 30332-0400, United States
| | - Veaceslav Coropceanu
- School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology , Atlanta, Georgia 30332-0400, United States
| | - Jean-Luc Brédas
- School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology , Atlanta, Georgia 30332-0400, United States
- KAUST Solar Center, Division of Physical Science and Engineering, King Abdullah University of Science and Technology , Thuwal 23955-6900, Saudi Arabia
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39
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Menke SM, Sadhanala A, Nikolka M, Ran NA, Ravva MK, Abdel-Azeim S, Stern HL, Wang M, Sirringhaus H, Nguyen TQ, Brédas JL, Bazan GC, Friend RH. Limits for Recombination in a Low Energy Loss Organic Heterojunction. ACS NANO 2016; 10:10736-10744. [PMID: 27809478 DOI: 10.1021/acsnano.6b06211] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Donor-acceptor organic solar cells often show high quantum yields for charge collection, but relatively low open-circuit voltages (VOC) limit power conversion efficiencies to around 12%. We report here the behavior of a system, PIPCP:PC61BM, that exhibits very low electronic disorder (Urbach energy less than 27 meV), very high carrier mobilities in the blend (field-effect mobility for holes >10-2 cm2 V-1 s-1), and a very low driving energy for initial charge separation (50 meV). These characteristics should give excellent performance, and indeed, the VOC is high relative to the donor energy gap. However, we find the overall performance is limited by recombination, with formation of lower-lying triplet excitons on the donor accounting for 90% of the recombination. We find this is a bimolecular process that happens on time scales as short as 100 ps. Thus, although the absence of disorder and the associated high carrier mobility speeds up charge diffusion and extraction at the electrodes, which we measure as early as 1 ns, this also speeds up the recombination channel, giving overall a modest quantum yield of around 60%. We discuss strategies to remove the triplet exciton recombination channel.
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Affiliation(s)
- S Matthew Menke
- Department of Physics, Cavendish Laboratory, University of Cambridge , J.J. Thompson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Aditya Sadhanala
- Department of Physics, Cavendish Laboratory, University of Cambridge , J.J. Thompson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Mark Nikolka
- Department of Physics, Cavendish Laboratory, University of Cambridge , J.J. Thompson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Niva A Ran
- Center for Polymers and Organic Solids, University of California , Santa Barbara, California 93106, United States
| | - Mahesh Kumar Ravva
- Solar & Photovoltaics Engineering Research Center, Division of Physical Science and Engineering, King Abdullah University of Science and Technology , Thuwal 23955-6900, Saudi Arabia
| | - Safwat Abdel-Azeim
- Solar & Photovoltaics Engineering Research Center, Division of Physical Science and Engineering, King Abdullah University of Science and Technology , Thuwal 23955-6900, Saudi Arabia
| | - Hannah L Stern
- Department of Physics, Cavendish Laboratory, University of Cambridge , J.J. Thompson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Ming Wang
- Center for Polymers and Organic Solids, University of California , Santa Barbara, California 93106, United States
| | - Henning Sirringhaus
- Department of Physics, Cavendish Laboratory, University of Cambridge , J.J. Thompson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Thuc-Quyen Nguyen
- Center for Polymers and Organic Solids, University of California , Santa Barbara, California 93106, United States
| | - Jean-Luc Brédas
- Solar & Photovoltaics Engineering Research Center, Division of Physical Science and Engineering, King Abdullah University of Science and Technology , Thuwal 23955-6900, Saudi Arabia
| | - Guillermo C Bazan
- Center for Polymers and Organic Solids, University of California , Santa Barbara, California 93106, United States
| | - Richard H Friend
- Department of Physics, Cavendish Laboratory, University of Cambridge , J.J. Thompson Avenue, Cambridge CB3 0HE, United Kingdom
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40
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Goldey MB, Reid D, de Pablo J, Galli G. Planarity and multiple components promote organic photovoltaic efficiency by improving electronic transport. Phys Chem Chem Phys 2016; 18:31388-31399. [PMID: 27722501 DOI: 10.1039/c6cp04999k] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Establishing how the conformation of organic photovoltaic (OPV) polymers affects their electronic and transport properties is critical in order to determine design rules for new OPV materials and in particular to understand the performance enhancements recently reported for ternary blends. We report coupled classical and ab initio molecular dynamics simulations showing that polymer linkage twisting significantly reduces optical absorption efficiency, as well as hole transport rates in donor polymers. We predict that blends with components favoring planar geometries contribute to the enhancement of the overall efficiency of ternary OPVs. Furthermore, our electronic structure calculations for the PTB7-PID2-PC71BM system show that hole transfer rates are enhanced in ternary blends with respect to their binary counterpart. Finally, our results point at thermal disorder in the blend as a key reason responsible for device voltage losses and at the need to carry out electronic structure calculations at finite temperature to reliably compare with experiments.
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Affiliation(s)
- Matthew B Goldey
- Institute for Molecular Engineering, The University of Chicago, Chicago, Illinois, USA.
| | - Daniel Reid
- Institute for Molecular Engineering, The University of Chicago, Chicago, Illinois, USA.
| | - Juan de Pablo
- Institute for Molecular Engineering, The University of Chicago, Chicago, Illinois, USA.
| | - Giulia Galli
- Institute for Molecular Engineering, The University of Chicago, Chicago, Illinois, USA.
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41
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Kaya S, Banerjee P, Saha SK, Tüzün B, Kaya C. Theoretical evaluation of some benzotriazole and phospono derivatives as aluminum corrosion inhibitors: DFT and molecular dynamics simulation approaches. RSC Adv 2016. [DOI: 10.1039/c6ra14548e] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The adsorption and corrosion inhibition properties of some benzotriazole and phospono derivatives namely, (PBTA), (TBTA), (PAA) and (PBA) molecules on the corrosion of aluminum were investigated by quantum chemical calculations and by molecular dynamics simulations.
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Affiliation(s)
- Savaş Kaya
- Cumhuriyet University
- Faculty of Science
- Department of Chemistry
- Sivas
- Turkey
| | - Priyabrata Banerjee
- Surface Engineering and Tribology Group
- CSIR-Central Mechanical Engineering Research Institute
- Durgapur 713209
- India
- Academy of Scientific and Innovative Research (AcSIR)
| | - Sourav Kr. Saha
- Surface Engineering and Tribology Group
- CSIR-Central Mechanical Engineering Research Institute
- Durgapur 713209
- India
- Academy of Scientific and Innovative Research (AcSIR)
| | - Burak Tüzün
- Cumhuriyet University
- Faculty of Science
- Department of Chemistry
- Sivas
- Turkey
| | - Cemal Kaya
- Cumhuriyet University
- Faculty of Science
- Department of Chemistry
- Sivas
- Turkey
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