1
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De S, Asthana D, Thirmal C, Keshri SK, Ghosh RK, Hundal G, Kumar R, Singh S, Chatterjee R, Mukhopadhyay P. A folded π-system with supramolecularly oriented dipoles: single-component piezoelectric relaxor with NLO activity. Chem Sci 2023; 14:2547-2552. [PMID: 36908941 PMCID: PMC9993858 DOI: 10.1039/d2sc06141d] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 12/29/2022] [Indexed: 01/05/2023] Open
Abstract
Organic molecules with an active dipole moment have a natural propensity to align in an antiparallel fashion in the solid state, resulting in zero macroscopic polarization. This primary limitation makes the material unresponsive to switching with electric fields, mechanical forces, and to intense laser light. A single-component organic material that bestows macroscopic dipole-driven electro-mechanical and optical functions, e.g., piezoelectric, ferroelectric and nonlinear optical (NLO) activity, is unprecedented due to the design challenges imparted by crystal symmetry and dipole orientations. Herein we report a crystalline organic material that self-assembles with a polar order (P 1), and is endowed with a high piezoelectric coefficient (d 33-47 pm V-1), as well as ferroelectric and Debye-type relaxor properties. In addition, it shows second harmonic generation (SHG) activity, which is more than five times that of the benchmark potassium dihydrogen phosphate. Piezoelectric force microscopy (PFM) images validated electro-mechanical deformations. Piezoresponse force spectroscopy (PFS) studies confirmed a signature butterfly-like amplitude and a phase loop. To the best of our knowledge, this is the first report of a folded supramolecular π-system that manifests unidirectionally oriented dipoles and exhibits piezoelectricity, ferroelectricity, and has excellent ability to generate second harmonic light. These findings can herald new design possibilities based on folded architectures to explore opto-, electro- and mechano-responsive multifaceted functions.
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Affiliation(s)
- Soumi De
- School of Physical Sciences, Jawaharlal Nehru University New Delhi - 110067 India
| | - Deepak Asthana
- Department of Chemistry, Ashoka University Sonipat Haryana 131029 India
| | - Chinthakuntla Thirmal
- Department of Physics, Indian Institute of Technology Delhi New Delhi - 110016 India.,VNR Vignana Jyothi Institute of Engineering and Technology Hyderabad Telangana 500 090 India
| | - Sudhir K Keshri
- School of Physical Sciences, Jawaharlal Nehru University New Delhi - 110067 India
| | - Ram Krishna Ghosh
- Department of Electronics & Communications Engineering, Indraprastha Institute of Information Technology Delhi New Delhi 110020 India
| | - Geeta Hundal
- Department of Chemistry, Guru Nanak Dev University Amritsar Punjab-143005 India
| | - Raju Kumar
- Special Centre for Nanoscience, Jawaharlal Nehru University New Delhi - 110067 India
| | - Satyendra Singh
- Special Centre for Nanoscience, Jawaharlal Nehru University New Delhi - 110067 India
| | - Ratnamala Chatterjee
- Department of Physics, Indian Institute of Technology Delhi New Delhi - 110016 India
| | - Pritam Mukhopadhyay
- School of Physical Sciences, Jawaharlal Nehru University New Delhi - 110067 India
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2
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Xie RF, Zhang JB, Wu Y, Li L, Liu XY, Cui G. Non-negligible roles of charge transfer excitons in ultrafast excitation energy transfer dynamics of a double-walled carbon nanotube. J Chem Phys 2023; 158:054108. [PMID: 36754819 DOI: 10.1063/5.0134353] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Herein, we employed a developed linear response time dependent density functional theory-based nonadiabatic dynamics simulation method that explicitly takes into account the excitonic effects to investigate photoinduced excitation energy transfer dynamics of a double-walled carbon nanotube (CNT) model with different excitation energies. The E11 excitation of the outer CNT will generate a local excitation (LE) |out*〉 exciton due to its low energy, which does not induce any charge separation. In contrast, the E11 excitation of the inner CNT can generate four kinds of excitons with the LE exciton |in*〉 dominates. In the 500-fs dynamics simulation, the LE exciton |in*〉 and charge transfer (CT) excitons |out-in+〉 and |out+in-〉 are all gradually converted to the |out*〉 exciton, corresponding to a photoinduced excitation energy transfer, which is consistent with experimental studies. Finally, when the excitation energy is close to the E22 state of the outer CNT (∼1.05 eV), a mixed population of different excitons, with the |out*〉 exciton dominated, is generated. Then, photoinduced energy transfer from the outer to inner CNTs occurs in the first 50 fs, which is followed by an inner to outer excitation energy transfer that is completed in 400 fs. The present work not only sheds important light on the mechanistic details of wavelength-dependent excitation energy transfer of a double-walled CNT model but also demonstrates the roles and importance of CT excitons in photoinduced excitation energy transfer. It also emphasized that explicitly including the excitonic effects in electronic structure calculations and nonadiabatic dynamics simulations is significant for correct understanding/rational design of optoelectronic properties of periodically extended systems.
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Affiliation(s)
- Rui-Fang Xie
- College of Chemistry and Material Science, Sichuan Normal University, Chengdu 610068, China
| | - Jing-Bin Zhang
- College of Chemistry and Material Science, Sichuan Normal University, Chengdu 610068, China
| | - Yang Wu
- College of Chemistry and Material Science, Sichuan Normal University, Chengdu 610068, China
| | - Laicai Li
- 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
| | - Ganglong Cui
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
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3
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Sebastian E, Sunny J, Hariharan M. Excimer evolution hampers symmetry-broken charge-separated states. Chem Sci 2022; 13:10824-10835. [PMID: 36320683 PMCID: PMC9491171 DOI: 10.1039/d2sc04387d] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Accepted: 08/18/2022] [Indexed: 08/26/2023] Open
Abstract
Achieving long-lived symmetry-broken charge-separated states in chromophoric assemblies is quintessential for enhanced performance of artificial photosynthetic mimics. However, the occurrence of energy trap states hinders exciton and charge transport across photovoltaic devices, diminishing power conversion efficiency. Herein, we demonstrate unprecedented excimer formation in the relaxed excited-state geometry of bichromophoric systems impeding the lifetime of symmetry-broken charge-separated states. Core-annulated perylenediimide dimers (SC-SPDI2 and SC-NPDI2) prefer a near-orthogonal arrangement in the ground state and a π-stacked foldamer structure in the excited state. The prospect of an excimer-like state in the foldameric arrangement of SC-SPDI2 and SC-NPDI2 has been rationalized by fragment-based excited state analysis and temperature-dependent photoluminescence measurements. Effective electronic coupling matrix elements in the Franck-Condon geometry of SC-SPDI2 and SC-NPDI2 facilitate solvation-assisted ultrafast symmetry-breaking charge-separation (SB-CS) in a high dielectric environment, in contrast to unrelaxed excimer formation (Ex*) in a low dielectric environment. Subsequently, the SB-CS state dissociates into an undesired relaxed excimer state (Ex) due to configuration mixing of a Frenkel exciton (FE) and charge-separated state in the foldamer structure, downgrading the efficacy of the charge-separated state. The decay rate constant of the FE to SB-CS (k FE→SB-CS) in polar solvents is 8-17 fold faster than that of direct Ex* formation (k FE→Ex*) in non-polar solvent (k FE→SB-CS≫k FE→Ex*), characterized by femtosecond transient absorption (fsTA) spectroscopy. The present investigation establishes the impact of detrimental excimer formation on the persistence of the SB-CS state in chromophoric dimers and offers the requisite of conformational rigidity as one of the potential design principles for developing advanced molecular photovoltaics.
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Affiliation(s)
- Ebin Sebastian
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram Maruthamala P.O., Vithura Thiruvananthapuram Kerala 695551 India
| | - Jeswin Sunny
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram Maruthamala P.O., Vithura Thiruvananthapuram Kerala 695551 India
| | - Mahesh Hariharan
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram Maruthamala P.O., Vithura Thiruvananthapuram Kerala 695551 India
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4
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Fukamizo S, Ikeda H, Tsurumaki E, Toyota S. An Alternative Synthesis of Tribenzodecacyclenes and Experimental Barrier to Propeller Inversion. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2022. [DOI: 10.1246/bcsj.20220015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Shun Fukamizo
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2–12–1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Hiroshi Ikeda
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2–12–1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
- Tokyo Metropolitan College of Industrial Technology, 1-10-40 Higashi-Oi, Shinagawa-ku, Tokyo 140-0011, Japan
| | - Eiji Tsurumaki
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2–12–1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Shinji Toyota
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2–12–1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
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5
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Kong J, Zhang W, Shao JY, Huo D, Niu X, Wan Y, Song D, Zhong YW, Xia A. Bridge-Length- and Solvent-Dependent Charge Separation and Recombination Processes in Donor-Bridge-Acceptor Molecules. J Phys Chem B 2021; 125:13279-13290. [PMID: 34814686 DOI: 10.1021/acs.jpcb.1c08308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The photoinduced intramolecular charge separation (CS) and charge recombination (CR) phenomena in a series of donor-bridge-acceptor (D-B-A) molecules are intensively investigated as a means of understanding electron transport through the π-B. Pyrene (Pyr) and triarylamine (TAA) moieties connected via phenylene Bs of various lengths are studied because their CS and CR behaviors can be readily monitored in real time by femtosecond transient absorption (fs-TA) spectroscopy. By combining the steady-state and fs-TA spectroscopic measurements in a variety of solvents together with chemical calculations, the parameters that govern the CS behaviors of these dyads were obtained, such as the solvent effects on free energy and the B-length-dependent electronic coupling (VDA) between D and A. We observed the sharp switch of the CS behavior with the increase of the solvent polarity and B-linker lengths. Furthermore, in the case of the shortest distance between D and A when the electron coupling is sufficiently large, we observed that the CS phenomenon occurs even in low-polar solvents. Upon increasing the length of B, CS occurs only in strong polar solvents. The distance-dependent decay constant of the CS rate is determined as ∼0.53 Å-1, indicating that CS is governed by superexchange tunneling interactions. The CS rate constants are also approximately estimated using Marcus electron transfer theory, and the results imply that the VDA value is the key factor dominating the CS rate, while the facile rotation of the phenylene B is important for modulating the lifetime of the charge-separated state in these D-B-A dyads. These results shed light on the practical strategy for obtaining a high CS efficiency with a long-lived CS state in TAA-B-Pyr derivatives.
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Affiliation(s)
- Jie Kong
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.,University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Wei Zhang
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.,University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Jiang-Yang Shao
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Dayujia Huo
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Xinmiao Niu
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.,University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Yan Wan
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Di Song
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.,School of Science, Beijing University of Posts and Telecommunications (BUPT), Beijing 100876, People's Republic of China
| | - Yu-Wu Zhong
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.,University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Andong Xia
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.,School of Science, Beijing University of Posts and Telecommunications (BUPT), Beijing 100876, People's Republic of China
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6
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Sebastian E, Hariharan M. Null Exciton-Coupled Chromophoric Dimer Exhibits Symmetry-Breaking Charge Separation. J Am Chem Soc 2021; 143:13769-13781. [PMID: 34370481 DOI: 10.1021/jacs.1c05793] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A comprehensive understanding of the structure-property relationships in multichromophoric architectures has pushed the limits for developing robust photosynthetic mimics and molecular photovoltaics. The elusive phenomenon of null exciton splitting has gathered immense attention in recent years owing to the occurrence in unique chromophoric architectures and consequent emergent properties. Herein, we unveil the hitherto unobserved null exciton coupling assisted highly efficient photoinduced symmetry-breaking charge separation (SB-CS) in a Greek cross (+)-oriented spiro-conjugated perylenediimide dimer (Sp-PDI2). Quantum chemical calculations have rationalized the infrequent manifestation of null exciton coupling behavior in Sp-PDI2. Negligible contribution of long-range Coulombic and short-range charge-transfer mediated coupling renders a monomer-like spectroscopic signature for Sp-PDI2 in toluene. The Greek cross (+)-arranged Sp-PDI2 possesses a selective hole-transfer coupling, facilitating the ultrafast dissociation of null excitons and evolution of the charge-separated state in polar solvents. Radical cationic and anionic spectroscopic signatures were characterized by employing femtosecond transient absorption spectroscopy. The substantial hole transfer electronic coupling and lower activation energy barrier of Sp-PDI2 accelerated the charge separation rate. The rate of charge recombination (CR) markedly decelerated due to falling into the inverted region of the Marcus parabola, where the driving force of CR is larger than the total reorganization energy for CR. Hence, the ratio of the rates for SB-CS over CR of Sp-PDI2 exhibited an unprecedently high value of 2647 in acetonitrile. The current study provides impeccable evidence for the role of selective charge filtering in governing efficient SB-CS and thereby novel insights towards the design of biomimics and advanced functional materials.
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Affiliation(s)
- Ebin Sebastian
- 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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7
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Madhu M, Ramakrishnan R, Vijay V, Hariharan M. Free Charge Carriers in Homo-Sorted π-Stacks of Donor-Acceptor Conjugates. Chem Rev 2021; 121:8234-8284. [PMID: 34133137 DOI: 10.1021/acs.chemrev.1c00078] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Inspired by the high photoconversion efficiency observed in natural light-harvesting systems, the hierarchical organization of molecular building blocks has gained impetus in the past few decades. Particularly, the molecular arrangement and packing in the active layer of organic solar cells (OSCs) have garnered significant attention due to the decisive role of the nature of donor/acceptor (D/A) heterojunctions in charge carrier generation and ultimately the power conversion efficiency. This review focuses on the recent developments in emergent optoelectronic properties exhibited by self-sorted donor-on-donor/acceptor-on-acceptor arrangement of covalently linked D-A systems, highlighting the ultrafast excited state dynamics of charge transfer and transport. Segregated organization of donors and acceptors promotes the delocalization of photoinduced charges among the stacks, engendering an enhanced charge separation lifetime and percolation pathways with ambipolar conductivity and charge carrier yield. Covalently linking donors and acceptors ensure a sufficient D-A interface and interchromophoric electronic coupling as required for faster charge separation while providing better control over their supramolecular assemblies. The design strategies to attain D-A conjugate assemblies with optimal charge carrier generation efficiency, the scope of their application compared to state-of-the-art OSCs, current challenges, and future opportunities are discussed in the review. An integrated overview of rational design approaches derived from the comprehension of underlying photoinduced processes can pave the way toward superior optoelectronic devices and bring in new possibilities to the avenue of functional supramolecular architectures.
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Affiliation(s)
- Meera Madhu
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram, Kerala, India 695551
| | - Remya Ramakrishnan
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram, Kerala, India 695551
| | - Vishnu Vijay
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram, Kerala, India 695551
| | - Mahesh Hariharan
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram, Kerala, India 695551
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8
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Lijina MP, Benny A, Ramakrishnan R, Nair NG, Hariharan M. Exciton Isolation in Cross-Pentacene Architecture. J Am Chem Soc 2020; 142:17393-17402. [DOI: 10.1021/jacs.0c06016] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- M. P. Lijina
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram, Kerala 695551, India
| | - Alfy Benny
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram, Kerala 695551, India
| | - Remya Ramakrishnan
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram, Kerala 695551, India
| | - Nanditha G. Nair
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram, Kerala 695551, India
| | - Mahesh Hariharan
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram, Kerala 695551, India
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9
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Ramakrishnan R, Niyas MA, Lijina MP, Hariharan M. Distinct Crystalline Aromatic Structural Motifs: Identification, Classification, and Implications. Acc Chem Res 2019; 52:3075-3086. [PMID: 31449389 DOI: 10.1021/acs.accounts.9b00320] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Spatial noncovalent helical organization of nucleobases in DNA and radial organization of chromophores in natural light-harvesting systems are fascinating yet enigmatic. Understanding the numerous weak interactions that drive the formation of elegant supramolecular architectures in native natural systems and developing bioinspired design strategies have seen a surge of interest in recent decades. Self-assembly of functional chromophores in the crystalline phase is a definitive strategy to identify novel molecule-molecule interactions, in particular, atom-atom interactions, and to understand the synergistic nature of noncovalent interactions that stabilizes the supramolecular organization. This Account narrates our recent efforts in developing desirable supramolecular motifs employing weak interaction-based strategies and our observation of deviations from the common motifs chartered in aromatic systems. Modulation of long-range aromatic interactions through chemical modifications (acylation, benzoylation, haloacylation, and alkylation of chromophores) to attain a preferred stacking (herringbone, lamellar, or columnar) is presented. Particular attention has been given to attaining lamellar or columnar packing possessing potential interchromophoric electronic coupling mediated high charge mobility. Supramolecular arrangements of noncovalently or covalently associated donor-acceptor systems that open up additional possibilities of packing modes (segregated, mixed etc.) are explored. Our persistent efforts yielded distinct twisted-segregated and alternate distichous stacks for the nonparallel covalently linked donor-acceptor systems that favor a long-lived photoinduced charge-separated state. We further move on to discuss the unconventional packing motifs that were identified recently. The highly sought-after Greek cross (+) stacking of chromophores in crystalline phase and an elegant crystalline radial arrangement of chromophores are examined. The Greek cross (+) stacked architecture exhibits monomer-like emission characteristics owing to the absence of exciton coupling across the orthogonally stacked chromophores. Crystalline helical chromophore assembly is yet another emerging motif with far-reaching applications in domains ranging from asymmetric catalysis to chiral smart materials and has been accounted here by citing certain phenomenal examples from literature. Thus, this Account demonstrates that identifying and classifying new structural motifs based on topological aspects, such as interchromophoric orientation (cross) and extended chromophore arrangement in the crystal lattice (radial, helical, etc.), are crucial since such fundamental characteristics dictate the properties emerging out of the corresponding motifs. Encouraged from ours and others' works, we propose the addition of new aromatic supramolecular structural motifs, namely, cross-stacked, helical, and radial arrangements, in order to expand the classification. We believe that identifying new emergent property-based supramolecular motifs and investigating the methods to achieve the desired motif will eventually have implications in fundamental crystal engineering, supramolecular chemistry, and biomimetic design of functional materials.
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Affiliation(s)
- Remya Ramakrishnan
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram, Kerala 695551, India
| | - M. A. Niyas
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram, Kerala 695551, India
| | - M. P. Lijina
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram, Kerala 695551, India
| | - Mahesh Hariharan
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram, Kerala 695551, India
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10
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Philip AM, Manikandan SK, Shaji A, Hariharan M. Concerted Interplay of Excimer and Dipole Coupling Governs the Exciton Relaxation Dynamics in Crystalline Anthracenes. Chemistry 2018; 24:18089-18096. [PMID: 30260513 DOI: 10.1002/chem.201804139] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Indexed: 11/08/2022]
Abstract
A combined theoretical and experimental investigation into the role of concerted long- (dipole coupling) and short-range (orbital overlap mediated excimer) electronic interactions in modulating the emission of six crystalline acetylanthracenes (1-3) is reported. Friedel-Crafts acylation of anthracene rendered crystalline acetylanthracenes with discrete close packing, varied orbital overlap, and resultant distinct emission (blue-green-yellow) from cooperative excimer and dipole coupling. Time-resolved emission spectroscopy (TRES) studies and the Kasha's exciton theory based quantitative estimation of dipole coupling (mean-field approximation) substantiates the exciton dynamics in crystalline 1-3. Extension of the Kasha's exciton model beyond the traditional nearest-neighbor approach, and consistent agreement among the computed spectral shifts and TRES temporal components, corroborate a holistic approach to decipher the exciton relaxation dynamics in the molecular assembly of novel photonic materials.
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Affiliation(s)
- Abbey M Philip
- School of Chemistry, Indian Institute of Science Education, and Research Thiruvananthapuram (IISER-TVM), Maruthamala P. O., Vithura, Thiruvananthapuram, Kerala, 695551, India
| | - Sreenath K Manikandan
- School of Physics, Indian Institute of Science Education, and Research Thiruvananthapuram (IISER-TVM), Maruthamala P. O., Vithura, Thiruvananthapuram, Kerala, 695551, India.,Present Address: Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627, USA
| | - Anil Shaji
- School of Physics, Indian Institute of Science Education, and Research Thiruvananthapuram (IISER-TVM), Maruthamala P. O., Vithura, Thiruvananthapuram, Kerala, 695551, India
| | - Mahesh Hariharan
- School of Chemistry, Indian Institute of Science Education, and Research Thiruvananthapuram (IISER-TVM), Maruthamala P. O., Vithura, Thiruvananthapuram, Kerala, 695551, India
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11
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Sebastian E, Philip AM, Benny A, Hariharan M. Null Exciton Splitting in Chromophoric Greek Cross (+) Aggregate. Angew Chem Int Ed Engl 2018; 57:15696-15701. [PMID: 30338635 DOI: 10.1002/anie.201810209] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Indexed: 12/29/2022]
Abstract
Exciton interactions in molecular aggregates play a crucial role in tailoring the optical behaviour of π-conjugated materials. Though vital for optoelectronic applications, ideal Greek cross-dipole (α=90°) stacking of chromophores remains elusive. We report a novel Greek cross (+) assembly of 1,7-dibromoperylene-3,4,9,10-tetracarboxylic tetrabutylester (PTE-Br2 ) which exhibits null exciton coupling mediated monomer-like optical characteristics in the crystalline state. In contrast, nonzero exciton coupling in X-type (α=70.2°, PTE-Br0 ) and J-type (α=0°, θ=48.4°, PTE-Br4 ) assemblies have perturbed optical properties. Additionally, the semi-classical Marcus theory of charge-transfer rates predicts a selective hole transport phenomenon in the orthogonally stacked PTE-Br2 . Precise rotation angle dependent optoelectronic properties in crystalline PTE-Br2 can have consequences in the rational design of novel π-conjugated materials for photonic and molecular electronic applications.
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Affiliation(s)
- Ebin Sebastian
- School of Chemistry, Indian Institute of Science Education and Research, Thiruvananthapuram (IISER-TVM), Maruthamala P. O., Vithura, Thiruvananthapuram, Kerala, 695551, India
| | - Abbey M Philip
- School of Chemistry, Indian Institute of Science Education and Research, Thiruvananthapuram (IISER-TVM), Maruthamala P. O., Vithura, Thiruvananthapuram, Kerala, 695551, India
| | - Alfy Benny
- School of Chemistry, Indian Institute of Science Education and Research, Thiruvananthapuram (IISER-TVM), Maruthamala P. O., Vithura, Thiruvananthapuram, Kerala, 695551, India
| | - Mahesh Hariharan
- School of Chemistry, Indian Institute of Science Education and Research, Thiruvananthapuram (IISER-TVM), Maruthamala P. O., Vithura, Thiruvananthapuram, Kerala, 695551, India
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12
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Sebastian E, Philip AM, Benny A, Hariharan M. Null Exciton Splitting in Chromophoric Greek Cross (+) Aggregate. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201810209] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Ebin Sebastian
- School of Chemistry; Indian Institute of Science Education and Research, Thiruvananthapuram (IISER-TVM); Maruthamala P. O., Vithura Thiruvananthapuram Kerala 695551 India
| | - Abbey M. Philip
- School of Chemistry; Indian Institute of Science Education and Research, Thiruvananthapuram (IISER-TVM); Maruthamala P. O., Vithura Thiruvananthapuram Kerala 695551 India
| | - Alfy Benny
- School of Chemistry; Indian Institute of Science Education and Research, Thiruvananthapuram (IISER-TVM); Maruthamala P. O., Vithura Thiruvananthapuram Kerala 695551 India
| | - Mahesh Hariharan
- School of Chemistry; Indian Institute of Science Education and Research, Thiruvananthapuram (IISER-TVM); Maruthamala P. O., Vithura Thiruvananthapuram Kerala 695551 India
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13
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Park SK, Kim JH, Park SY. Organic 2D Optoelectronic Crystals: Charge Transport, Emerging Functions, and Their Design Perspective. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1704759. [PMID: 29663536 DOI: 10.1002/adma.201704759] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 12/21/2017] [Indexed: 06/08/2023]
Abstract
2D organic semiconductor crystals are emerging as a fascinating platform with regard to their applications in organic field-effect transistors (OFETs), attributed to their enhanced charge transport efficiency and their new optoelectronic functions, based on their unique morphological features. Advances in material processing techniques have not only enabled easy fabrication of few-monolayered 2D nanostructures but also facilitated exploration of the interesting properties induced by characteristic 2D morphologies. However, to date, only a limited number of representative organic semiconductors have been utilized in organic 2D optoelectronics. Therefore, in order to further spur this research, an intuitive crystal engineering principle for realizing organic 2D crystals is required. In this regard, here, not only the important implications of applying 2D structures to OFET devices are discussed but also a crystal engineering protocol is provided that first predicts molecular arrangements depending on the molecular factors, which is followed by realizing 2D supramolecular synthon networks for different molecular packing motifs. It is expected that 2D organic semiconductor crystals developed by this approach will pave a promising way toward next-generation organic 2D optoelectronics.
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Affiliation(s)
- Sang Kyu Park
- Center for Supramolecular Optoelectronic Materials, Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-744, South Korea
| | - Jin Hong Kim
- Center for Supramolecular Optoelectronic Materials, Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-744, South Korea
| | - Soo Young Park
- Center for Supramolecular Optoelectronic Materials, Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-744, South Korea
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14
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Viable access to the triplet excited state in peryleneimide based palladium complex
$$^{\S }$$
§. J CHEM SCI 2018. [DOI: 10.1007/s12039-018-1537-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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15
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Umeyama T, Imahori H. Electron transfer and exciplex chemistry of functionalized nanocarbons: effects of electronic coupling and donor dimerization. NANOSCALE HORIZONS 2018; 3:352-366. [PMID: 32254123 DOI: 10.1039/c8nh00024g] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In the past few decades, research on the construction of donor-bridge-acceptor linked systems capable of efficient photoinduced charge separation has fundamentally contributed to the fields of artificial photosynthesis and solar energy conversion. Specifically, the above systems are often fabricated by using carbon-based nanomaterials such as fullerenes, carbon nanotubes, and graphenes, offering limitless possibilities of tuning their optical and electronic properties. Accordingly, since understanding the structure-photodynamics relationships of π-aromatic donor-bridge-nanocarbon linked systems is crucial for extracting the full potential of nanocarbon materials, this review summarizes recent research on their photophysical properties featuring nanocarbon materials as electron acceptors. In particular, we highlight the electronic coupling effects on the photodynamics of donor-bridge-nanocarbon acceptor linked systems, together with the effects of donor dimerization. On a basis of their time-resolved spectroscopic data, the photodynamics of donor-bridge-nanocarbon acceptor linked systems is shown to be substantially influenced by the formation and decay of an exciplex state, i.e., an excited-state consisting of a π-molecular donor and a nanocarbon acceptor with partial charge-transfer character. Such basic information is essential for realizing future application of carbon-based nanomaterials in optoelectronic and energy conversion devices.
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Affiliation(s)
- Tomokazu Umeyama
- Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan.
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16
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Rajagopal SK, K. N, Deb S, Bhat V, Sasikumar D, Sebastian E, Hariharan M. Extending the scope of the carbonyl facilitated triplet excited state towards visible light excitation. Phys Chem Chem Phys 2018; 20:19120-19128. [DOI: 10.1039/c8cp01023d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A series of extended π-conjugated benzophenone analogs was synthesized through a facile Lewis-acid catalyzed Friedel–Crafts reaction in order to exploit the integral triplet state properties of benzophenone.
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Affiliation(s)
- Shinaj K. Rajagopal
- School of Chemistry
- Indian Institute of Science Education and Research Thiruvananthapuram (IISER-TVM)
- Thiruvananthapuram 695551
- India
| | - Nagaraj K.
- School of Chemistry
- Indian Institute of Science Education and Research Thiruvananthapuram (IISER-TVM)
- Thiruvananthapuram 695551
- India
| | - Somadrita Deb
- School of Chemistry
- Indian Institute of Science Education and Research Thiruvananthapuram (IISER-TVM)
- Thiruvananthapuram 695551
- India
| | - Vinayak Bhat
- School of Chemistry
- Indian Institute of Science Education and Research Thiruvananthapuram (IISER-TVM)
- Thiruvananthapuram 695551
- India
| | - Devika Sasikumar
- School of Chemistry
- Indian Institute of Science Education and Research Thiruvananthapuram (IISER-TVM)
- Thiruvananthapuram 695551
- India
| | - Ebin Sebastian
- School of Chemistry
- Indian Institute of Science Education and Research Thiruvananthapuram (IISER-TVM)
- Thiruvananthapuram 695551
- India
| | - Mahesh Hariharan
- School of Chemistry
- Indian Institute of Science Education and Research Thiruvananthapuram (IISER-TVM)
- Thiruvananthapuram 695551
- India
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