1
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Gan Z, Gloor CJ, Yan L, Zhong X, You W, Moran AM. Elucidating phonon dephasing mechanisms in layered perovskites with coherent Raman spectroscopies. J Chem Phys 2024; 161:074202. [PMID: 39158047 DOI: 10.1063/5.0216472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Accepted: 07/29/2024] [Indexed: 08/20/2024] Open
Abstract
Organic-inorganic hybrid perovskite quantum wells exhibit electronic structures with properties intermediate between those of inorganic semiconductors and molecular crystals. In these systems, periodic layers of organic spacer molecules occupy the interstitial spaces between perovskite sheets, thereby confining electronic excitations to two dimensions. Here, we investigate spectroscopic line broadening mechanisms for phonons coupled to excitons in lead-iodide layered perovskites with phenyl ethyl ammonium (PEA) and azobenzene ethyl ammonium (AzoEA) spacer cations. Using a modified Elliot line shape analysis for the absorbance and photoluminescence spectra, polaron binding energies of 11.2 and 17.5 meV are calculated for (PEA)2PbI4 and (AzoEA)2PbI4, respectively. To determine whether the polaron stabilization processes influence the dephasing mechanisms of coupled phonons, five-pulse coherent Raman spectroscopies are applied to the two systems under electronically resonant conditions. The prominence of inhomogeneous line broadening mechanisms detected in (AzoEA)2PbI4 suggests that thermal fluctuations involving the deformable organic phase broaden the distributions of phonon frequencies within the quantum wells. In addition, our data indicate that polaron stabilization primarily involves photoinduced reorganization of the organic phases for both systems, whereas the impulsively excited phonons represent less than 10% of the total polaron binding energy. The signal generation mechanisms associated with our fifth-order coherent Raman experiments are explored with a perturbative model in which cumulant expansions are used to account for time-coincident vibrational dephasing and polaron stabilization processes.
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Affiliation(s)
- Zijian Gan
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Camryn J Gloor
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Liang Yan
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Xiaowei Zhong
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Wei You
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Andrew M Moran
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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2
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LeCroy G, Ghosh R, Sommerville P, Burke C, Makki H, Rozylowicz K, Cheng C, Weber M, Khelifi W, Stingelin N, Troisi A, Luscombe C, Spano FC, Salleo A. Using Molecular Structure to Tune Intrachain and Interchain Charge Transport in Indacenodithiophene-Based Copolymers. J Am Chem Soc 2024; 146:21778-21790. [PMID: 39058936 DOI: 10.1021/jacs.4c06006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/28/2024]
Abstract
In this work, we compare two structurally near-amorphous rigid-rod polymers─poly(indacenodithiophene-co-benzothiadiazole), p(IDT-BT), and poly(indacenodithiophene-co-benzopyrollodione), p(IDT-BPD)─with orders of magnitude different mobilities to understand the effect charge carrier intrachain delocalization has on electronic transport. Quantum chemical calculations show that p(IDT-BPD) has a barrier to torsion that is significantly lower than that of p(IDT-BT) and is thus more likely to have reduced conjugation lengths. We utilize absorption and photoluminescence spectroscopy to characterize energetic disorder and show that p(IDT-BPD) has higher energetic disorder. Charge modulation spectroscopy (CMS) and model calculations are used to show that charge carriers are substantially delocalized in p(IDT-BT) and occupy near-uniform energetic environments. We find that mobility activated hopping barriers are similar in these two materials. Electronic structure calculations show that both intrachain and interchain couplings of monomer units are poor enough in p(IDT-BPD) that charge carriers collapse to single IDT units and transport via a through-space tunneling mechanism. This work highlights the remarkable charge transport properties of p(IDT-BT) by showing that high mobilities are achievable on device-relevant length scales with only 1D carrier delocalization.
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Affiliation(s)
- Garrett LeCroy
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Raja Ghosh
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Parker Sommerville
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, United States
| | - Colm Burke
- Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, United Kingdom
| | - Hesam Makki
- Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, United Kingdom
| | - Kalee Rozylowicz
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Christina Cheng
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Mark Weber
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Wissem Khelifi
- pi-Conjugated Polymers Unit, Okinawa Institute of Science and Technology, Onna, Okinawa 904-0495, Japan
| | - Natalie Stingelin
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Alessandro Troisi
- Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, United Kingdom
| | - Christine Luscombe
- pi-Conjugated Polymers Unit, Okinawa Institute of Science and Technology, Onna, Okinawa 904-0495, Japan
| | - Frank C Spano
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Alberto Salleo
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
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3
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Kopp SM, Redman AJ, Rončević I, Schröder L, Bogani L, Anderson HL, Timmel CR. Charge and Spin Transfer Dynamics in a Weakly Coupled Porphyrin Dimer. J Am Chem Soc 2024; 146:21476-21489. [PMID: 39042706 PMCID: PMC11311228 DOI: 10.1021/jacs.4c04186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2024]
Abstract
The dynamics of electron and spin transfer in the radical cation and photogenerated triplet states of a tetramethylbiphenyl-linked zinc-porphyrin dimer were investigated, so as to test the relevant parameters for the design of a single-molecule spin valve and the creation of a novel platform for the photogeneration of high-multiplicity spin states. We used a combination of multiple techniques, including variable-temperature continuous wave EPR, pulsed proton electron-nuclear double resonance (ENDOR), transient EPR, and optical spectroscopy. The conclusions are further supported by density functional theory (DFT) calculations and comparison to reference compounds. The low-temperature cw-EPR and room-temperature near-IR spectra of the dimer monocation demonstrate that the radical cation is spatially localized on one side of the dimer at any point in time, not coherently delocalized over both porphyrin units. The EPR spectra at 298 K reveal rapid hopping of the radical spin density between both sites of the dimer via reversible intramolecular electron transfer. The hyperfine interactions are modulated by electron transfer and can be quantified using ENDOR spectroscopy. This allowed simulation of the variable-temperature cw-EPR spectra with a two-site exchange model and provided information on the temperature-dependence of the electron transfer rate. The electron transfer rates range from about 10.0 MHz at 200 K to about 53.9 MHz at 298 K. The activation enthalpies Δ‡H of the electron transfer were determined as Δ‡H = 9.55 kJ mol-1 and Δ‡H = 5.67 kJ mol-1 in a 1:1:1 solvent mixture of CD2Cl2/toluene-d8/THF-d8 and in 2-methyltetrahydrofuran, respectively, consistent with a Robin-Day class II mixed valence compound. These results indicate that the interporphyrin electronic coupling in a tetramethylbiphenyl-linked porphyrin dimer is suitable for the backbone of a single-molecule spin valve. Investigation of the spin density distribution of the photogenerated triplet state of the Zn-porphyrin dimer reveals localization of the triplet spin density on a nanosecond time scale on one-half of the dimer at 20 K in 2-methyltetrahydrofuran and at 250 K in a polyvinylcarbazole film. This establishes the porphyrin dimer as a molecular platform for the formation of a localized, photogenerated triplet state on one porphyrin unit that is coupled to a second redox-active, ground-state porphyrin unit, which can be explored for the formation of high-multiplicity spin states.
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Affiliation(s)
- Sebastian M Kopp
- Centre for Advanced Electron Spin Resonance, Department of Chemistry, University of Oxford, Oxford, OX1 3QR, U.K
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, U.K
| | - Ashley J Redman
- Centre for Advanced Electron Spin Resonance, Department of Chemistry, University of Oxford, Oxford, OX1 3QR, U.K
| | - Igor Rončević
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, U.K
| | - Lisa Schröder
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, U.K
| | - Lapo Bogani
- Department of Materials, University of Oxford, Oxford, OX1 3PH, U.K
| | - Harry L Anderson
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, U.K
| | - Christiane R Timmel
- Centre for Advanced Electron Spin Resonance, Department of Chemistry, University of Oxford, Oxford, OX1 3QR, U.K
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4
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Zhang ZH, Wu L, Miao MP, Qin HJ, Chen G, Cai M, Liu L, Zhu LF, Zhang W, Zhai T, Ji W, Fu YS. Discovery and Manipulation of van der Waals Polarons in Sb 2O 3 Ultrathin Molecular Crystal. J Am Chem Soc 2024; 146:18556-18564. [PMID: 38943576 DOI: 10.1021/jacs.4c04450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/01/2024]
Abstract
Manipulating single electrons at the atomic scale is vital for mastering complex surface processes governed by the transfer of individual electrons. Polarons, composed of electrons stabilized by electron-phonon coupling, offer a pivotal medium for such manipulation. Here, using scanning tunneling microscopy and spectroscopy (STM/STS) and density functional theory (DFT) calculations, we report the identification and manipulation of a new type of polaron, dubbed van der Waals (vdW) polaron, within mono- to trilayer ultrathin films composed of Sb2O3 molecules that are bonded via vdW attractions. The Sb2O3 films were grown on a graphene-covered SiC(0001) substrate via molecular beam epitaxy. Unlike prior molecular polarons, STM imaging observed polarons at the interstitial sites of the molecular film, presenting unique electronic states and localized band bending. DFT calculations revealed the lowest conduction band as an intermolecular bonding state, capable of ensnaring an extra electron through locally diminished intermolecular distances, thereby forming an intermolecular vdW polaron. We also demonstrated the ability to generate, move, and erase such vdW polarons using an STM tip. Our work uncovers a new type of polaron stabilized by coupling with intermolecular vibrations where vdW interactions dominate, paving the way for designing atomic-scale electron transfer processes and enabling precise tailoring of electron-related properties and functionalities.
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Affiliation(s)
- Zhi-Hao Zhang
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Linlu Wu
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing 100872, China
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing 100872, China
| | - Mao-Peng Miao
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Hao-Jun Qin
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Gang Chen
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Min Cai
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Lixin Liu
- State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Lan-Fang Zhu
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Wenhao Zhang
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Tianyou Zhai
- State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Wei Ji
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing 100872, China
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing 100872, China
| | - Ying-Shuang Fu
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
- Wuhan Institute of Quantum Technology, Wuhan 430206, China
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5
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Sayer T, Montoya-Castillo A. Generalized quantum master equations can improve the accuracy of semiclassical predictions of multitime correlation functions. J Chem Phys 2024; 161:011101. [PMID: 38949578 DOI: 10.1063/5.0219205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Accepted: 06/12/2024] [Indexed: 07/02/2024] Open
Abstract
Multitime quantum correlation functions are central objects in physical science, offering a direct link between the experimental observables and the dynamics of an underlying model. While experiments such as 2D spectroscopy and quantum control can now measure such quantities, the accurate simulation of such responses remains computationally expensive and sometimes impossible, depending on the system's complexity. A natural tool to employ is the generalized quantum master equation (GQME), which can offer computational savings by extending reference dynamics at a comparatively trivial cost. However, dynamical methods that can tackle chemical systems with atomistic resolution, such as those in the semiclassical hierarchy, often suffer from poor accuracy, limiting the credence one might lend to their results. By combining work on the accuracy-boosting formulation of semiclassical memory kernels with recent work on the multitime GQME, here we show for the first time that one can exploit a multitime semiclassical GQME to dramatically improve both the accuracy of coarse mean-field Ehrenfest dynamics and obtain orders of magnitude efficiency gains.
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Affiliation(s)
- Thomas Sayer
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, USA
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6
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Shahu A, Petropoulos V, Saridakis E, Petrakis VS, Ioannidis N, Mitrikas G, Schiza A, Chochos CL, Kasimati EM, Soultati A, Nika MC, Thomaidis NS, Fakis M, Maiuri M, Cerullo G, Pistolis G. Aggregation-Driven Photoinduced α-C(sp 3)-H Bond Hydroxylation/C(sp 3)-C(sp 3) Coupling of Boron Dipyrromethene Dye in Water Reported by Near-Infrared Emission. J Am Chem Soc 2024; 146:15659-15665. [PMID: 38819953 PMCID: PMC11190975 DOI: 10.1021/jacs.4c02019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 05/23/2024] [Accepted: 05/28/2024] [Indexed: 06/02/2024]
Abstract
Molecular aggregation is a powerful tool for tuning advanced materials' photophysical and electronic properties. Here we present a novel potential for the aqueous-solvated aggregated state of boron dipyrromethene (BODIPY) to facilitate phototransformations otherwise achievable only under harsh chemical conditions. We show that the photoinduced symmetry-breaking charge separation state can itself initiate catalyst-free redox chemistry, leading to selective α-C(sp3)-H bond activation/Csp3-Csp3 coupling on the BODIPY backbone. The photoproduction progress was tracked by monitoring the evolution of the strong Stokes-shifted near-infrared emission, resulting from selective self-assembly of the terminal heterodimeric photoproduct into well-ordered J-aggregates, as revealed by X-ray structural analysis. These findings provide a facile and green route to further explore the promising frontier of packing-triggered selective photoconversions via supramolecular engineering.
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Affiliation(s)
- Adelajda Shahu
- Department
of Chemistry, National and Kapodistrian
University of Athens, Athens 15771, Greece
- Institute
of Nanoscience & Nanotechnology, NCSR
“Demokritos”, Athens 15310, Greece
| | - Vasilis Petropoulos
- Department
of Physics, University of Patras, Patras 26504, Greece
- Department
of Physics, Politecnico di Milano, Milano 20133, Italy
| | - Emmanuel Saridakis
- Institute
of Nanoscience & Nanotechnology, NCSR
“Demokritos”, Athens 15310, Greece
| | - Vyron S. Petrakis
- Department
of Chemistry, National and Kapodistrian
University of Athens, Athens 15771, Greece
- Institute
of Nanoscience & Nanotechnology, NCSR
“Demokritos”, Athens 15310, Greece
| | - Nikolaos Ioannidis
- Institute
of Nanoscience & Nanotechnology, NCSR
“Demokritos”, Athens 15310, Greece
| | - George Mitrikas
- Institute
of Nanoscience & Nanotechnology, NCSR
“Demokritos”, Athens 15310, Greece
| | - Andriana Schiza
- Department
of Chemistry, National and Kapodistrian
University of Athens, Athens 15771, Greece
- Institute
of Chemical Biology, National Hellenic Research
Foundation, Athens 11635, Greece
| | - Christos L. Chochos
- Institute
of Chemical Biology, National Hellenic Research
Foundation, Athens 11635, Greece
| | | | - Anastasia Soultati
- Institute
of Nanoscience & Nanotechnology, NCSR
“Demokritos”, Athens 15310, Greece
| | - Maria Christina Nika
- Department
of Chemistry, National and Kapodistrian
University of Athens, Athens 15771, Greece
| | - Nikolaos S. Thomaidis
- Department
of Chemistry, National and Kapodistrian
University of Athens, Athens 15771, Greece
| | - Mihalis Fakis
- Department
of Physics, University of Patras, Patras 26504, Greece
| | | | - Giulio Cerullo
- Department
of Physics, Politecnico di Milano, Milano 20133, Italy
| | - George Pistolis
- Institute
of Nanoscience & Nanotechnology, NCSR
“Demokritos”, Athens 15310, Greece
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7
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Zoppellaro G, Medveď M, Hrubý V, Zbořil R, Otyepka M, Lazar P. Solvent Controlled Generation of Spin Active Polarons in Two-Dimensional Material under UV Light Irradiation. J Am Chem Soc 2024; 146:15010-15018. [PMID: 38696712 PMCID: PMC11157526 DOI: 10.1021/jacs.3c13296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 04/16/2024] [Accepted: 04/17/2024] [Indexed: 05/04/2024]
Abstract
Polarons belong to a class of extensively studied quasiparticles that have found applications spanning diverse fields, including charge transport, colossal magnetoresistance, thermoelectricity, (multi)ferroism, optoelectronics, and photovoltaics. It is notable, though, that their interaction with the local environment has been overlooked so far. We report an unexpected phenomenon of the solvent-induced generation of polaronic spin active states in a two-dimensional (2D) material fluorographene under UV light. Furthermore, we present compelling evidence of the solvent-specific nature of this phenomenon. The generation of spin-active states is robust in acetone, moderate in benzene, and absent in cyclohexane. Continuous wave X-band electron paramagnetic resonance (EPR) spectroscopy experiments revealed a massive increase in the EPR signal for fluorographene dispersed in acetone under UV-light irradiation, while the system did not show any significant signal under dark conditions and without the solvent. The patterns appeared due to the generation of transient magnetic photoexcited states of polaronic character, which encompassed the net 1/2 spin moment detectable by EPR. Advanced ab initio calculations disclosed that polarons are plausibly formed at radical sites in fluorographene which interact strongly with acetone molecules in their vicinity. Additionally, we present a comprehensive scenario for multiplication of polaronic spin active species, highlighting the pivotal role of the photoinduced charge transfer from the solvent to the electrophilic radical centers in fluorographene. We believe that the solvent-tunable polaron formation with the use of UV light and an easily accessible 2D nanomaterial opens up a wide range of future applications, ranging from molecular sensing to magneto-optical devices.
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Affiliation(s)
- Giorgio Zoppellaro
- Regional
Centre of Advanced Technologies and Materials, The Czech Advanced
Technology and Research Institute (CATRIN), Palacký University Olomouc, Šlechtitelů 27, Olomouc 779 00, Czech Republic
- Nanotechnology
Centre, Centre for Energy and Environmental Technologies (CEET), VŠB—Technical University of Ostrava, 17. listopadu 2172/15, Ostrava-Poruba 708 00, Czech Republic
| | - Miroslav Medveď
- Regional
Centre of Advanced Technologies and Materials, The Czech Advanced
Technology and Research Institute (CATRIN), Palacký University Olomouc, Šlechtitelů 27, Olomouc 779 00, Czech Republic
- Department
of Chemistry, Faculty of Natural Sciences, Matej Bel University, Tajovského 40, Banská Bystrica 974 01, Slovak
Republic
| | - Vítězslav Hrubý
- Regional
Centre of Advanced Technologies and Materials, The Czech Advanced
Technology and Research Institute (CATRIN), Palacký University Olomouc, Šlechtitelů 27, Olomouc 779 00, Czech Republic
- Department
of Physical Chemistry, Faculty of Science, Palacký University Olomouc, 17. listopadu 12, Olomouc 771 46, Czech Republic
| | - Radek Zbořil
- Regional
Centre of Advanced Technologies and Materials, The Czech Advanced
Technology and Research Institute (CATRIN), Palacký University Olomouc, Šlechtitelů 27, Olomouc 779 00, Czech Republic
- Nanotechnology
Centre, Centre for Energy and Environmental Technologies (CEET), VŠB—Technical University of Ostrava, 17. listopadu 2172/15, Ostrava-Poruba 708 00, Czech Republic
| | - Michal Otyepka
- Regional
Centre of Advanced Technologies and Materials, The Czech Advanced
Technology and Research Institute (CATRIN), Palacký University Olomouc, Šlechtitelů 27, Olomouc 779 00, Czech Republic
- IT4Innovations, VŠB − Technical
University of Ostrava, 17. listopadu 2172/15, Ostrava-Poruba 708 00, Czech Republic
| | - Petr Lazar
- Regional
Centre of Advanced Technologies and Materials, The Czech Advanced
Technology and Research Institute (CATRIN), Palacký University Olomouc, Šlechtitelů 27, Olomouc 779 00, Czech Republic
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8
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Jindal V, Aldahdooh MKR, Gomez ED, Janik MJ, Milner ST. Tight-binding model predicts exciton energetics and structure for photovoltaic molecules. Phys Chem Chem Phys 2024; 26:15472-15483. [PMID: 38751347 DOI: 10.1039/d4cp00554f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
Conjugated molecules and polymers are being designed as acceptor and donor materials for organic photovoltaic (OPV) cells. OPV performance depends on generation of free charge carriers through dissociation of excitons, which are electron-hole pairs created when a photon is absorbed. Here, we develop a tight-binding model to describe excitons on homo-oligomers, alternating co-oligomers, and a non-fullerene acceptor - IDTBR. We parameterize our model using density functional theory (DFT) energies of neutral, anion, cation, and excited states of constituent moieties. A symmetric molecule like IDTBR has two ends where an exciton can sit; but the product wavefunction approximation for the exciton breaks symmetry. So, we introduce a tight-binding model with full correlation between electron and hole, which allows the exciton to coherently explore both ends of the molecule. Our approach predicts optical singlet excitation energies for oligomers of varying length as well as IDTBR in good agreement with time-dependent DFT and spectroscopic results.
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Affiliation(s)
- Vishal Jindal
- Department of Chemical Engineering, The Pennsylvania State University, USA.
| | | | - Enrique D Gomez
- Department of Chemical Engineering, The Pennsylvania State University, USA.
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Michael J Janik
- Department of Chemical Engineering, The Pennsylvania State University, USA.
| | - Scott T Milner
- Department of Chemical Engineering, The Pennsylvania State University, USA.
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802, USA
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9
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Su F, Hong Y, Zhang G, Wu K, Kim J, Chen Z, Zhang HJ, Kim D, Lin J. Two-dimensional radial-π-stacks in solution. Chem Sci 2024; 15:5604-5611. [PMID: 38638221 PMCID: PMC11023034 DOI: 10.1039/d4sc00195h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 03/11/2024] [Indexed: 04/20/2024] Open
Abstract
Highly organized π-aggregate architectures can strongly affect electronic couplings, leading to important photophysical behaviors. With the escalating interest in two-dimensional (2D) materials attributed to their exceptional electronic and optical characteristics, there is growing anticipation that 2D radial-π-stacks built upon radial π-conjugation nanorings, incorporating intra- and inter-ring electronic couplings within the confines of a 2D plane, will exhibit superior topological attributes and distinct properties. Despite their immense potential, the design and synthesis of 2D π-stacks have proven to be a formidable challenge due to the insufficient π-π interactions necessary for stable stacking. In this study, we present the successful preparation of single-layer 2D radial-π-stacks in a solution. Pillar-shaped radially π-conjugated [4]cyclo-naphthodithiophene diimide ([4]C-NDTIs) molecules were tetragonally arranged via in-plane intermolecular π-π interactions. These 2D π-stacks have a unique topology that differs from that of conventional 1D π-stacks and exhibit notable properties, such as acting as a 2D template capable of absorbing C60 guest molecules and facilitating the formation of 2D radial-π-stacks comprising [4]C-NDTI-C60 complexes, rapid exciton delocalization across the 2D plane, and efficient excitation energy funneling towards a trap.
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Affiliation(s)
- Feng Su
- Department of Chemistry, College of Chemistry and Chemical Engineering, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, Xiamen University Xiamen 361005 P. R. China
| | - Yongseok Hong
- Department of Chemistry, Yonsei University Seoul 03722 Korea
| | - Guilan Zhang
- Department of Chemistry, College of Chemistry and Chemical Engineering, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, Xiamen University Xiamen 361005 P. R. China
| | - Kongchuan Wu
- Department of Chemistry, College of Chemistry and Chemical Engineering, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, Xiamen University Xiamen 361005 P. R. China
| | - Juno Kim
- Department of Chemistry, Yonsei University Seoul 03722 Korea
| | - Zhi Chen
- College of Chemistry and Environmental Engineering, Shenzhen University Shenzhen 518060 China
| | - Hui-Jun Zhang
- Department of Chemistry, College of Chemistry and Chemical Engineering, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, Xiamen University Xiamen 361005 P. R. China
| | - Dongho Kim
- Department of Chemistry, Yonsei University Seoul 03722 Korea
- Division of Energy Materials, Pohang University of Science and Technology (POSTECH) Pohang 37673 Korea
| | - Jianbin Lin
- Department of Chemistry, College of Chemistry and Chemical Engineering, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, Xiamen University Xiamen 361005 P. R. China
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10
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Dyksik M, Beret D, Baranowski M, Duim H, Moyano S, Posmyk K, Mlayah A, Adjokatse S, Maude DK, Loi MA, Puech P, Plochocka P. Polaron Vibronic Progression Shapes the Optical Response of 2D Perovskites. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2305182. [PMID: 38072637 PMCID: PMC10870061 DOI: 10.1002/advs.202305182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 11/23/2023] [Indexed: 02/17/2024]
Abstract
The optical response of 2D layered perovskites is composed of multiple equally-spaced spectral features, often interpreted as phonon replicas, separated by an energy Δ ≃ 12 - 40 meV, depending upon the compound. Here the authors show that the characteristic energy spacing, seen in both absorption and emission, is correlated with a substantial scattering response above ≃ 200 cm-1 (≃ 25 meV) observed in resonant Raman. This peculiar high-frequency signal, which dominates both Stokes and anti-Stokes regions of the scattering spectra, possesses the characteristic spectral fingerprints of polarons. Notably, its spectral position is shifted away from the Rayleigh line, with a tail on the high energy side. The internal structure of the polaron consists of a series of equidistant signals separated by 25-32 cm-1 (3-4 meV), depending upon the compound, forming a polaron vibronic progression. The observed progression is characterized by a large Huang-Rhys factor (S > 6) for all of the 2D layered perovskites investigated here, indicative of a strong charge carrier - lattice coupling. The polaron binding energy spans a range ≃ 20-35 meV, which is corroborated by the temperature-dependent Raman scattering data. The investigation provides a complete understanding of the optical response of 2D layered perovskites via the direct observation of polaron vibronic progression. The understanding of polaronic effects in perovskites is essential, as it directly influences the suitability of these materials for future opto-electronic applications.
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Affiliation(s)
- Mateusz Dyksik
- Department of Experimental PhysicsFaculty of Fundamental Problems of TechnologyWroclaw University of Science and TechnologyWroclaw50370Poland
| | - Dorian Beret
- CEMES‐UPR8011CNRSUniversity of Toulouse29 rue Jeanne MarvigToulouse31500France
| | - Michal Baranowski
- Department of Experimental PhysicsFaculty of Fundamental Problems of TechnologyWroclaw University of Science and TechnologyWroclaw50370Poland
| | - Herman Duim
- Zernike Institute for Advanced MaterialsUniversity of GroningenNijenborgh 4Groningen9747 AGThe Netherlands
| | - Sébastien Moyano
- CEMES‐UPR8011CNRSUniversity of Toulouse29 rue Jeanne MarvigToulouse31500France
| | - Katarzyna Posmyk
- Department of Experimental PhysicsFaculty of Fundamental Problems of TechnologyWroclaw University of Science and TechnologyWroclaw50370Poland
- Laboratoire National des Champs Magnétiques IntensesEMFL, CNRS UPR 3228University Toulouse, University Toulouse 3, INSA‐T, University Grenoble AlpesGrenoble and ToulouseFrance
| | - Adnen Mlayah
- LAASUniversity of ToulouseCNRS, UPS, 7 Avenue du Colonel RocheToulouse31031France
| | - Sampson Adjokatse
- Zernike Institute for Advanced MaterialsUniversity of GroningenNijenborgh 4Groningen9747 AGThe Netherlands
| | - Duncan K. Maude
- Laboratoire National des Champs Magnétiques IntensesEMFL, CNRS UPR 3228University Toulouse, University Toulouse 3, INSA‐T, University Grenoble AlpesGrenoble and ToulouseFrance
| | - Maria Antonietta Loi
- Zernike Institute for Advanced MaterialsUniversity of GroningenNijenborgh 4Groningen9747 AGThe Netherlands
| | - Pascal Puech
- CEMES‐UPR8011CNRSUniversity of Toulouse29 rue Jeanne MarvigToulouse31500France
| | - Paulina Plochocka
- Department of Experimental PhysicsFaculty of Fundamental Problems of TechnologyWroclaw University of Science and TechnologyWroclaw50370Poland
- Laboratoire National des Champs Magnétiques IntensesEMFL, CNRS UPR 3228University Toulouse, University Toulouse 3, INSA‐T, University Grenoble AlpesGrenoble and ToulouseFrance
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11
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Tang J, Zhang G, Wang C, Deng L, Zhu X, Yu H, Wang K, Li J. Investigation of the Role of K 2SO 4 Electrolyte in Hole Transport Layer for Efficient Quasi-2D Perovskite Light-Emitting Diodes. J Phys Chem Lett 2024; 15:1112-1120. [PMID: 38262437 DOI: 10.1021/acs.jpclett.3c03417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2024]
Abstract
Quasi-two-dimensional (2D) perovskite light-emitting diodes are promising light sources for color display and lighting. However, poor carrier injection and transport between the bottom hole transport layer (HTL) and perovskite limit the device performance. Here we demonstrate a simple and effective way to modify the HTL for enhancing the performance of perovskite light-emitting diodes (PeLEDs). An electrolyte K2SO4 is used to mix with poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) as the hole transport layer. The K+ doping helped the quasi-2D perovskite phases grow vertically along the interface of the PEDOT:PSS, fine-modulate the phase distribution, and simultaneously reduce the defect density of quasi-2D perovskites. It also significantly reduced the exciton quenching and injection barrier at PEDOT:PSS and quasi-2D perovskite interface. The optimized green PeLEDs with the K2SO4 doped PEDOT:PSS HTL showed a maximum luminance of 17185 cd/m2 which is almost 4.7 times brighter than the control one, with a maximum external quantum efficiency of 18.64%.
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Affiliation(s)
- Jun Tang
- Key Laboratory of Luminescence and Optical Information, Ministry of Education, School of Physical Science and Engineering, Beijing Jiaotong University, Beijing 100044, China
| | - Guoshuai Zhang
- Key Laboratory of Luminescence and Optical Information, Ministry of Education, School of Physical Science and Engineering, Beijing Jiaotong University, Beijing 100044, China
| | - Chenming Wang
- Key Laboratory of Luminescence and Optical Information, Ministry of Education, School of Physical Science and Engineering, Beijing Jiaotong University, Beijing 100044, China
| | - Liangliang Deng
- Center of Micro-Nano System, School of Information Science and Technology, Fudan University, Shanghai 200438, China
| | - Xixiang Zhu
- Key Laboratory of Luminescence and Optical Information, Ministry of Education, School of Physical Science and Engineering, Beijing Jiaotong University, Beijing 100044, China
| | - Haomiao Yu
- Key Laboratory of Luminescence and Optical Information, Ministry of Education, School of Physical Science and Engineering, Beijing Jiaotong University, Beijing 100044, China
| | - Kai Wang
- Key Laboratory of Luminescence and Optical Information, Ministry of Education, School of Physical Science and Engineering, Beijing Jiaotong University, Beijing 100044, China
| | - Jinpeng Li
- Key Laboratory of Luminescence and Optical Information, Ministry of Education, School of Physical Science and Engineering, Beijing Jiaotong University, Beijing 100044, China
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12
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LeCroy G, Ghosh R, Untilova V, Guio L, Stone KH, Brinkmann M, Luscombe C, Spano FC, Salleo A. Polaron absorption in aligned conjugated polymer films: breakdown of adiabatic treatments and going beyond the conventional mid-gap state model. MATERIALS HORIZONS 2024; 11:545-553. [PMID: 37982315 DOI: 10.1039/d3mh01278f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2023]
Abstract
This study provides the first experimental polarized intermolecular and intramolecular optical absorption components of field-induced polarons in regioregular poly(3-hexylthiophene-2,5-diyl), rr-P3HT, a polymer semiconductor. Highly aligned rr-P3HT thin films were prepared by a high temperature shear-alignment process that orients polymer backbones along the shearing direction. rr-P3HT in-plane molecular orientation was measured by electron diffraction, and out-of-plane orientation was measured through series of synchrotron X-ray scattering techniques. Then, with molecular orientation quantified, polarized charge modulation spectroscopy was used to probe mid-IR polaron absorption in the ℏω = 0.075 - 0.75 eV range and unambiguously assign intermolecular and intramolecular optical absorption components of hole polarons in rr-P3HT. This data represents the first experimental quantification of these polarized components and allowed long-standing theoretical predictions to be compared to experimental results. The experimental data is discrepant with predictions of polaron absorption based on an adiabatic framework that works under the Born-Oppenheimer approximation, but the data is entirely consistent with a more recent nonadiabatic treatment of absorption based on a modified Holstein Hamiltonian. This nonadiabatic treatment was used to show that both intermolecular and intramolecular polaron coherence break down at length scales significantly smaller than estimated structural coherence in either direction. This strongly suggests that polaron delocalization is fundamentally limited by energetic disorder in rr-P3HT.
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Affiliation(s)
- Garrett LeCroy
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA.
| | - Raja Ghosh
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92037, USA
| | | | - Lorenzo Guio
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA
| | - Kevin H Stone
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Martin Brinkmann
- Université de Strasbourg, CNRS, ICS UPR 22, F-67000 Strasbourg, France
| | - Christine Luscombe
- pi-Conjugated Polymers Unit, Okinawa Institute of Science and Technology, Onna, Okinawa 904-0495, Japan
| | - Frank C Spano
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, USA
| | - Alberto Salleo
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA.
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13
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Song I, You L, Chen K, Lee WJ, Mei J. Chiroptical Switching of Electrochromic Polymer Thin Films. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2307057. [PMID: 37897242 DOI: 10.1002/adma.202307057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 10/17/2023] [Indexed: 10/30/2023]
Abstract
The interaction between light and chiroptical polymers plays a crucial role in chiroptics, spintronics, and chiral-spin selectivity. Despite considerable successes in creating dissymmetric polymer films, the elucidation of chiroptical activities under electrochemical switching remains unexplored. Here homogeneous chiral electrochromics is reported using chiral assembly of conjugated polymers through a transient solidification process with molecular chiral templates. In their neutral state, the chiral electrochromic polymers directly produce a remarkably dissymmetric polarization-dependent transmittance. The circular dichroism (CD) and dissymmetric transmission can be tuned by adjusting the doping level of the electrochemically active polymer films. Under high levels of oxidation, the chiroptical activities are reversed with strong bleaching in the visible, leading to formation of monosignate CD spectra over the infrared region. The matching between circular polarization handedness and chirality of chiroptical polymers makes a distinct impact on optical contrast and color switching dynamics due to the flipped chiroptical activities through polymer redox reactions. The differential circularly polarized transmission in the chiral see-through display can make a well-resolved color change in human eyes, demonstrating proof-of-concept devices for 3D imaging and information encryption. This work serves as a foundation to develop advanced on-chip fabrication of circular polarization-multiplexed display in flexible and highly integrated platforms.
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Affiliation(s)
- Inho Song
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Liyan You
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Ke Chen
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Won-June Lee
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Jianguo Mei
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA
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14
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Mathur D, Díaz SA, Hildebrandt N, Pensack RD, Yurke B, Biaggne A, Li L, Melinger JS, Ancona MG, Knowlton WB, Medintz IL. Pursuing excitonic energy transfer with programmable DNA-based optical breadboards. Chem Soc Rev 2023; 52:7848-7948. [PMID: 37872857 PMCID: PMC10642627 DOI: 10.1039/d0cs00936a] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Indexed: 10/25/2023]
Abstract
DNA nanotechnology has now enabled the self-assembly of almost any prescribed 3-dimensional nanoscale structure in large numbers and with high fidelity. These structures are also amenable to site-specific modification with a variety of small molecules ranging from drugs to reporter dyes. Beyond obvious application in biotechnology, such DNA structures are being pursued as programmable nanoscale optical breadboards where multiple different/identical fluorophores can be positioned with sub-nanometer resolution in a manner designed to allow them to engage in multistep excitonic energy-transfer (ET) via Förster resonance energy transfer (FRET) or other related processes. Not only is the ability to create such complex optical structures unique, more importantly, the ability to rapidly redesign and prototype almost all structural and optical analogues in a massively parallel format allows for deep insight into the underlying photophysical processes. Dynamic DNA structures further provide the unparalleled capability to reconfigure a DNA scaffold on the fly in situ and thus switch between ET pathways within a given assembly, actively change its properties, and even repeatedly toggle between two states such as on/off. Here, we review progress in developing these composite materials for potential applications that include artificial light harvesting, smart sensors, nanoactuators, optical barcoding, bioprobes, cryptography, computing, charge conversion, and theranostics to even new forms of optical data storage. Along with an introduction into the DNA scaffolding itself, the diverse fluorophores utilized in these structures, their incorporation chemistry, and the photophysical processes they are designed to exploit, we highlight the evolution of DNA architectures implemented in the pursuit of increased transfer efficiency and the key lessons about ET learned from each iteration. We also focus on recent and growing efforts to exploit DNA as a scaffold for assembling molecular dye aggregates that host delocalized excitons as a test bed for creating excitonic circuits and accessing other quantum-like optical phenomena. We conclude with an outlook on what is still required to transition these materials from a research pursuit to application specific prototypes and beyond.
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Affiliation(s)
- Divita Mathur
- Department of Chemistry, Case Western Reserve University, Cleveland OH 44106, USA
| | - Sebastián A Díaz
- Center for Bio/Molecular Science and Engineering, Code 6900, USA.
| | - Niko Hildebrandt
- Department of Chemistry, Seoul National University, Seoul 08826, South Korea
- Department of Engineering Physics, McMaster University, Hamilton, L8S 4L7, Canada
| | - Ryan D Pensack
- Micron School of Materials Science & Engineering, Boise State University, Boise, ID 83725, USA.
| | - Bernard Yurke
- Micron School of Materials Science & Engineering, Boise State University, Boise, ID 83725, USA.
| | - Austin Biaggne
- Micron School of Materials Science & Engineering, Boise State University, Boise, ID 83725, USA.
| | - Lan Li
- Micron School of Materials Science & Engineering, Boise State University, Boise, ID 83725, USA.
- Center for Advanced Energy Studies, Idaho Falls, ID 83401, USA
| | - Joseph S Melinger
- Electronics Science and Technology Division, Code 6800, U.S. Naval Research Laboratory, Washington, DC 20375, USA
| | - Mario G Ancona
- Electronics Science and Technology Division, Code 6800, U.S. Naval Research Laboratory, Washington, DC 20375, USA
- Department of Electrical and Computer Engineering, Florida State University, Tallahassee, FL 32310, USA
| | - William B Knowlton
- Micron School of Materials Science & Engineering, Boise State University, Boise, ID 83725, USA.
| | - Igor L Medintz
- Center for Bio/Molecular Science and Engineering, Code 6900, USA.
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15
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Nicolaidou E, Parker AW, Sazanovich IV, Towrie M, Hayes SC. Unraveling Excited State Dynamics of a Single-Stranded DNA-Assembled Conjugated Polyelectrolyte. J Phys Chem Lett 2023; 14:9794-9803. [PMID: 37883808 PMCID: PMC10641883 DOI: 10.1021/acs.jpclett.3c01803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Revised: 10/21/2023] [Accepted: 10/23/2023] [Indexed: 10/28/2023]
Abstract
Conformational templating of conjugated polyelectrolytes with single-stranded DNAs (ssDNAs) has the prospect of tailoring excited state dynamics for specific optoelectronic applications. We use ultrafast time-resolved infrared spectroscopy to study the photophysics of a cationic polythiophene assembled with different ssDNAs, inducing distinct conformations (flexible disordered structures vs more rigid complexes with increased backbone planarity). Intrachain polarons are always produced upon selective excitation of the polymer, the extent being dependent on backbone torsional order. Polaron formation and decay were monitored through evolution of IR-active vibrational modes that interfere with mid-IR polaron electronic absorption giving rise to Fano-antiresonances. Selective UV excitation of ssDNAs revealed that stacking interactions between thiophene rings and nucleic acid bases can promote the formation of an intermolecular charge transfer complex. The findings inform designers of functional conjugated polymers by identifying that involvement of the scaffold in the photophysics needs to be considered when developing such structures for optoelectronic applications.
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Affiliation(s)
- Eliana Nicolaidou
- Department
of Chemistry, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus
| | - Anthony W. Parker
- Central
Laser Facility, Research Complex at Harwell, Science and Technology
Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire OX11 0QX, U.K.
| | - Igor V. Sazanovich
- Central
Laser Facility, Research Complex at Harwell, Science and Technology
Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire OX11 0QX, U.K.
| | - Michael Towrie
- Central
Laser Facility, Research Complex at Harwell, Science and Technology
Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire OX11 0QX, U.K.
| | - Sophia C. Hayes
- Department
of Chemistry, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus
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16
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Nellissen AC, Fron E, Vandenwijngaerden JBF, De Feyter S, Mertens SFL, Van der Auweraer M. Spectroscopic Characterization of Thiacarbocyanine Dye Molecules Adsorbed on Hexagonal Boron Nitride: a Time-Resolved Study. ACS OMEGA 2023; 8:35638-35652. [PMID: 37810698 PMCID: PMC10552479 DOI: 10.1021/acsomega.3c02020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Accepted: 09/06/2023] [Indexed: 10/10/2023]
Abstract
Physisorption on hexagonal boron nitride (hBN) gained interest over the years thanks to its properties (chemically and thermally stable, insulating properties, etc.) and similarities to the well-known graphene. A recent study showed flat-on adsorption of several cationic thiacarbocyanine dyes on hBN with a tendency to form weakly coupled H- or I-type aggregates, while a zwitterionic thiacarbocyanine dye rather led to a tilted adsorption. With this in-depth time-resolved study using the TC-SPC technique, we confirm the results proven by adsorption isotherms, atomic force microscopy, and stationary state spectroscopy combined with molecular mechanics simulations and estimation of the corresponding exciton interaction. The absence of a systematic trend for the dependence of the decay times, normalized amplitudes of the decay components, and contribution of different components to the stationary emission spectra upon the emission wavelength observed for all studied dyes and coverages suggests the occurrence of a single emitting species. At low coverage levels, the non-mono-exponential character of the decays was attributed to adsorption on different sites characterized by different intramolecular rotational freedom or energy transfer to nonfluorescent traps or a combination of both. The difference between the decay rates of the four dyes reflects a different density of the nonfluorescent traps. Although the decay time of the unquenched dyes was in the order of magnitude of that of dye monomers in a rigid environment, it is also compatible with weakly coupled aggregates such as proposed earlier based on the stationary spectra. Hence, the adsorption leads to a rigid environment of the dyes, blocking internal conversion. Increasing the concentration of the dye solution from which the adsorption on hBN occurs increases not only the coverage of the hBN surface but also the extent of energy transfer to nonfluorescent traps. For TDC (5,5-dichloro-3-3'-diethyl-9-ethyl-thiacarbocyanine) and TD2 (3-3'-diethyl-9-ethyl-thiacarbocyanine), besides direct energy transfer to traps, exciton hopping between dye dimers followed by energy transfer to these traps occurs, which resulted in a decreasing decay time of the longest decaying component. For all dyes, it was also possible to analyze the fluorescence decays as a stretched exponential as would be expected for energy transfer to randomly distributed traps in a two-dimensional (2D) geometry. This analysis yielded a fluorescence decay time of the unquenched dyes similar to the longest decay time obtained by analysis of the fluorescence decays as a sum of three of four exponentials.
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Affiliation(s)
- Anne-Charlotte Nellissen
- Laboratory
for Photochemistry and Spectroscopy, KU
Leuven, Chem & Tech,
Celestijnenlaan 200F, 3001 Leuven, Belgium
| | - Eduard Fron
- Laboratory
for Photochemistry and Spectroscopy, KU
Leuven, Chem & Tech,
Celestijnenlaan 200F, 3001 Leuven, Belgium
| | | | - Steven De Feyter
- Laboratory
for Photochemistry and Spectroscopy, KU
Leuven, Chem & Tech,
Celestijnenlaan 200F, 3001 Leuven, Belgium
| | - Stijn F. L. Mertens
- Department
of Chemistry, Energy Lancaster and Materials Science Institute, Lancaster University, Bailrigg, LA1 4YB Lancaster, United Kingdom
| | - Mark Van der Auweraer
- Laboratory
for Photochemistry and Spectroscopy, KU
Leuven, Chem & Tech,
Celestijnenlaan 200F, 3001 Leuven, Belgium
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17
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Lindenthal S, Fazzi D, Zorn NF, El Yumin AA, Settele S, Weidinger B, Blasco E, Zaumseil J. Understanding the Optical Properties of Doped and Undoped 9-Armchair Graphene Nanoribbons in Dispersion. ACS NANO 2023; 17:18240-18252. [PMID: 37695780 PMCID: PMC10540269 DOI: 10.1021/acsnano.3c05246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Accepted: 09/07/2023] [Indexed: 09/13/2023]
Abstract
Graphene nanoribbons are one-dimensional stripes of graphene with width- and edge-structure-dependent electronic properties. They can be synthesized bottom-up in solution to obtain precise ribbon geometries. Here we investigate the optical properties of solution-synthesized 9-armchair graphene nanoribbons (9-aGNRs) that are stabilized as dispersions in organic solvents and further fractionated by liquid cascade centrifugation (LCC). Absorption and photoluminescence spectroscopy reveal two near-infrared absorption and emission peaks whose ratios depend on the LCC fraction. Low-temperature single-nanoribbon photoluminescence spectra suggest the presence of two different nanoribbon species. Based on density functional theory (DFT) and time-dependent DFT calculations, the lowest energy transition can be assigned to pristine 9-aGNRs, while 9-aGNRs with edge-defects, caused by incomplete graphitization, result in more blue-shifted transitions and higher Raman D/G-mode ratios. Hole doping of 9-aGNR dispersions with the electron acceptor F4TCNQ leads to concentration dependent bleaching and quenching of the main absorption and emission bands and the appearance of red-shifted, charge-induced absorption features but no additional emission peaks, thus indicating the formation of polarons instead of the predicted trions (charged excitons) in doped 9-aGNRs.
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Affiliation(s)
- Sebastian Lindenthal
- Institute
for Physical Chemistry, Heidelberg University, D-69120 Heidelberg, Germany
| | - Daniele Fazzi
- Department
of Chemistry “Giacomo Ciamician”, University of Bologna, 40126 Bologna, Italy
| | - Nicolas F. Zorn
- Institute
for Physical Chemistry, Heidelberg University, D-69120 Heidelberg, Germany
| | | | - Simon Settele
- Institute
for Physical Chemistry, Heidelberg University, D-69120 Heidelberg, Germany
| | - Britta Weidinger
- Institute
for Molecular Systems Engineering and Advanced Materials and Institute
of Organic Chemistry, Heidelberg University, D-69120 Heidelberg, Germany
| | - Eva Blasco
- Institute
for Molecular Systems Engineering and Advanced Materials and Institute
of Organic Chemistry, Heidelberg University, D-69120 Heidelberg, Germany
| | - Jana Zaumseil
- Institute
for Physical Chemistry, Heidelberg University, D-69120 Heidelberg, Germany
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18
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Montanaro A, Park KH, Fassioli F, Giusti F, Fausti D, Scholes GD. Manipulation of Charge Delocalization in a Bulk Heterojunction Material Using a Mid-Infrared Push Pulse. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2023; 127:13712-13722. [PMID: 37492193 PMCID: PMC10364132 DOI: 10.1021/acs.jpcc.3c02938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 06/07/2023] [Indexed: 07/27/2023]
Abstract
In organic bulk heterojunction materials, charge delocalization has been proposed to play a vital role in the generation of free carriers by effectively reducing the Coulomb attraction via an interfacial charge transfer exciton (CTX). Pump-push-probe (PPP) experiments produced evidence that the excess energy given by a push pulse enhances delocalization, thereby increasing photocurrent. However, previous studies have employed near-infrared push pulses in the range ∼0.4-0.6 eV, which is larger than the binding energy of a typical CTX. This raises the doubt that the push pulse may directly promote dissociation without involving delocalized states. Here, we perform PPP experiments with mid-infrared push pulses at energies that are well below the binding energy of a CTX state (0.12-0.25 eV). We identify three types of CTXs: delocalized, localized, and trapped. The excitation resides over multiple polymer chains in delocalized CTXs, while it is restricted to a single chain (albeit maintaining a degree of intrachain delocalization) in localized CTXs. Trapped CTXs are instead completely localized. The pump pulse generates a "hot" delocalized CTX, which promptly relaxes to a localized CTX and eventually to trapped states. We find that photo-exciting localized CTXs with push pulses resonant to the mid-infrared charge transfer absorption can promote delocalization and, in turn, contribute to the formation of long-lived charge separated states. On the other hand, we found that trapped CTXs are non-responsive to the push pulses. We hypothesize that delocalized states identified in prior studies are only accessible in systems where there is significant interchain electronic coupling or regioregularity that supports either inter- or intrachain polaron delocalization. This, in turn, emphasizes the importance of engineering the micromorphology and energetics of the donor-acceptor interface to exploit the full potential of a material for photovoltaic applications.
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Affiliation(s)
- Angela Montanaro
- Department of Physics, University of Trieste, Via A. Valerio 2, 34127 Trieste, Italy
- Elettra-Sincrotrone Trieste S.C.p.A., Strada Statale 14 - km 163.5 in AREA Science Park,
Basovizza, 34149 Trieste, Italy
- Department
of Physics, University of Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Kyu Hyung Park
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Francesca Fassioli
- Department
of Physics, University of Erlangen-Nürnberg, 91058 Erlangen, Germany
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- SISSA − Scuola Internazionale Superiore di Studi Avanzati, Trieste 34136, Italy
| | - Francesca Giusti
- Department of Physics, University of Trieste, Via A. Valerio 2, 34127 Trieste, Italy
- Elettra-Sincrotrone Trieste S.C.p.A., Strada Statale 14 - km 163.5 in AREA Science Park,
Basovizza, 34149 Trieste, Italy
| | - Daniele Fausti
- Department of Physics, University of Trieste, Via A. Valerio 2, 34127 Trieste, Italy
- Elettra-Sincrotrone Trieste S.C.p.A., Strada Statale 14 - km 163.5 in AREA Science Park,
Basovizza, 34149 Trieste, Italy
- Department
of Physics, University of Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Gregory D. Scholes
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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19
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Liu H, Wang A, Zhang P, Ma C, Chen C, Liu Z, Zhang YQ, Feng B, Cheng P, Zhao J, Chen L, Wu K. Atomic-scale manipulation of single-polaron in a two-dimensional semiconductor. Nat Commun 2023; 14:3690. [PMID: 37344475 DOI: 10.1038/s41467-023-39361-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 06/09/2023] [Indexed: 06/23/2023] Open
Abstract
Polaron is a composite quasiparticle derived from an excess carrier trapped by local lattice distortion, and it has been studied extensively for decades both theoretically and experimentally. However, atomic-scale creation and manipulation of single-polarons in real space have still not been achieved so far, which precludes the atomistic understanding of the properties of polarons as well as their applications. Herein, using scanning tunneling microscopy, we succeeded to create single polarons in a monolayer two-dimensional (2D) semiconductor, CoCl2. Combined with first-principles calculations, two stable polaron configurations, centered at atop and hollow sites, respectively, have been revealed. Remarkably, a series of manipulation progresses - from creation, erasure, to transition - can be accurately implemented on individual polarons. Our results pave the way to understand the physics of polaron at atomic level, and the easy control of single polarons in 2D semiconductor may open the door to 2D polaronics including the data storage.
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Affiliation(s)
- Huiru Liu
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, China
| | - Aolei Wang
- Department of Physics, University of Science and Technology of China, 230026, Hefei, Anhui, China
| | - Ping Zhang
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, China
| | - Chen Ma
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, China
| | - Caiyun Chen
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, China
| | - Zijia Liu
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, China
- Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China
| | - Yi-Qi Zhang
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, China
| | - Baojie Feng
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, China
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, 100871, Beijing, China
| | - Peng Cheng
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, China
| | - Jin Zhao
- Department of Physics, University of Science and Technology of China, 230026, Hefei, Anhui, China.
- ICQD/Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, 230026, Hefei, Anhui, China.
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, 15260, PA, USA.
- Hefei National Laboratory, University of Science and Technology of China, 230088, Hefei, Anhui, China.
| | - Lan Chen
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, China.
- Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China.
| | - Kehui Wu
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, China.
- Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China.
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, 100871, Beijing, China.
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20
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Abstract
Organic conjugated polymers have been pivotal in the development of organic electronics in applications such as in organic field effect transistors and photovoltaics. In these applications, the electronic structures of the polymers change by the gain or loss of charge. In this work, the visualization of charge delocalization in oligomeric and polymeric systems by range-separated density functional theory calculations reveals an efficient method of determining the polymer limit and polaron delocalization lengths of conjugated systems. Methods of displaying these data and the important computational details of the calculations are explored. These calculations provide researchers information about intrachain charge transport, donor-acceptor characteristics, and a method of validating that the computational model structures are indeed representative of the polymer and not just small molecules. Contributions from differing co-monomers to the polymer properties can be assessed through plotting the charge distributions along the polymer backbone. Visualization of polaron (de)localization can guide future polymer design, e.g., by placement of solubilizing chains to aid interchain interactions at polymer sections bearing greater polaron localization, or by minimizing charge accumulation at potentially reactive monomer units.
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Affiliation(s)
- Karl J Thorley
- Center for Applied Energy Research, University of Kentucky, Lexington, Kentucky 40511, United States
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21
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Colom E, Hernández-Ferrer J, Galán-González A, Ansón-Casaos A, Navarro-Rodríguez M, Palacios-Lidón E, Colchero J, Padilla J, Urbina A, Arenal R, Benito AM, Maser WK. Graphene Oxide: Key to Efficient Charge Extraction and Suppression of Polaronic Transport in Hybrids with Poly (3-hexylthiophene) Nanoparticles. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2023; 35:3522-3531. [PMID: 37181669 PMCID: PMC10173772 DOI: 10.1021/acs.chemmater.3c00008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 04/05/2023] [Indexed: 05/16/2023]
Abstract
Nanoparticles (NPs) of conjugated polymers in intimate contact with sheets of graphene oxide (GO) constitute a promising class of water-dispersible nanohybrid materials of increased interest for the design of sustainable and improved optoelectronic thin-film devices, revealing properties exclusively pre-established upon their liquid-phase synthesis. In this context, we report for the first time the preparation of a P3HTNPs-GO nanohybrid employing a miniemulsion synthesis approach, whereby GO sheets dispersed in the aqueous phase serve as a surfactant. We show that this process uniquely favors a quinoid-like conformation of the P3HT chains of the resulting NPs well located onto individual GO sheets. The accompanied change in the electronic behavior of these P3HTNPs, consistently confirmed by the photoluminescence and Raman response of the hybrid in the liquid and solid states, respectively, as well as by the properties of the surface potential of isolated individual P3HTNPs-GO nano-objects, facilitates unprecedented charge transfer interactions between the two constituents. While the electrochemical performance of nanohybrid films is featured by fast charge transfer processes, compared to those taking place in pure P3HTNPs films, the loss of electrochromic effects in P3HTNPs-GO films additionally indicates the unusual suppression of polaronic charge transport processes typically encountered in P3HT. Thus, the established interface interactions in the P3HTNPs-GO hybrid enable a direct and highly efficient charge extraction channel via GO sheets. These findings are of relevance for the sustainable design of novel high-performance optoelectronic device structures based on water-dispersible conjugated polymer nanoparticles.
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Affiliation(s)
- Eduardo Colom
- Instituto
de Carboquímica (ICB-CSIC), E-50011 Zaragoza, Spain
| | | | - Alejandro Galán-González
- Instituto
de Carboquímica (ICB-CSIC), E-50011 Zaragoza, Spain
- Centro
de Investigaciones Científicas Avanzadas, Universidade da Coruña (CICA), E-15008 San Vicenzo de Elviña, A Coruña, Spain
| | | | | | - Elisa Palacios-Lidón
- Departamento
de Física, Edificio CIOyN, Universidad
de Murcia, E-30100 Murcia, Spain
| | - Jaime Colchero
- Departamento
de Física, Edificio CIOyN, Universidad
de Murcia, E-30100 Murcia, Spain
| | - Javier Padilla
- Departamento
de Física Aplicada y Tec. Naval, Universidad Politécnica de Cartagena, E-30202 Cartagena, Spain
| | - Antonio Urbina
- Departamento
de Ciencias e Instituto de Materiales Avanzados y Matemáticas
(INAMAT), Universidad Pública
de Navarra (UPNA), E-31006 Pamplona, Spain
- Laboratorio
de Microscopias Avanzadas (LMA)Universidad
de Zaragoza, E-50018 Zaragoza, Spain
| | - Raul Arenal
- Instituto
de Nanociencia y Materiales de Aragón (INMA-CSIC-Univ. Zaragoza), E-50009 Zaragoza, Spain
- ARAID
Foundation, E-50018 Zaragoza, Spain
| | - Ana M. Benito
- Instituto
de Carboquímica (ICB-CSIC), E-50011 Zaragoza, Spain
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22
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Gera T, Chen L, Eisfeld A, Reimers JR, Taffet EJ, Raccah DIGB. Simulating optical linear absorption for mesoscale molecular aggregates: An adaptive hierarchy of pure states approach. J Chem Phys 2023; 158:2887556. [PMID: 37125709 DOI: 10.1063/5.0141882] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 03/07/2023] [Indexed: 05/02/2023] Open
Abstract
In this paper, we present dyadic adaptive HOPS (DadHOPS), a new method for calculating linear absorption spectra for large molecular aggregates. This method combines the adaptive HOPS (adHOPS) framework, which uses locality to improve computational scaling, with the dyadic HOPS method previously developed to calculate linear and nonlinear spectroscopic signals. To construct a local representation of dyadic HOPS, we introduce an initial state decomposition that reconstructs the linear absorption spectra from a sum over locally excited initial conditions. We demonstrate the sum over initial conditions can be efficiently Monte Carlo sampled and that the corresponding calculations achieve size-invariant [i.e., O(1)] scaling for sufficiently large aggregates while trivially incorporating static disorder in the Hamiltonian. We present calculations on the photosystem I core complex to explore the behavior of the initial state decomposition in complex molecular aggregates as well as proof-of-concept DadHOPS calculations on an artificial molecular aggregate inspired by perylene bis-imide to demonstrate the size-invariance of the method.
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Affiliation(s)
- Tarun Gera
- Department of Chemistry, Southern Methodist University, P.O. Box, Dallas, Texas 750314, USA
| | - Lipeng Chen
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Str. 38, Dresden, Germany
| | - Alexander Eisfeld
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Str. 38, Dresden, Germany
| | - Jeffrey R Reimers
- International Centre for Quantum and Molecular Structures and the School of Physics, Shanghai University, 200444 Shanghai, China
- School of Mathematical and Physical Sciences, University of Technology Sydney, Sydney NSW 2007, Australia
| | - Elliot J Taffet
- Department of Chemistry, Southern Methodist University, P.O. Box, Dallas, Texas 750314, USA
| | - Doran I G B Raccah
- Department of Chemistry, Southern Methodist University, P.O. Box, Dallas, Texas 750314, USA
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23
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Palacino-González E, Jansen TLC. Modeling the Effect of Disorder in the Two-Dimensional Electronic Spectroscopy of Poly-3-hexyltiophene in an Organic Photovoltaic Blend: A Combined Quantum/Classical Approach. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2023; 127:6793-6801. [PMID: 37081993 PMCID: PMC10108354 DOI: 10.1021/acs.jpcc.3c01080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 02/28/2023] [Indexed: 05/03/2023]
Abstract
We introduce a first-principles model of the 12-mer poly-3-hexyltiophene (P3HT) polymer system in the realistic description of an organic photovoltaic blend environment. We combine Molecular Dynamics (MD) simulations of a thin-film blend of P3HT and phenyl-C61-butyric acid methyl ester (PCBM) to model the interactions with a fluctuating environment with Time-Dependent Density Functional Theory (TDDFT) calculations to parametrize the effect of the torsional flexibility in the polymer and construct an exciton-type Hamiltonian that describes the photoexcitation of the polymer. This allows us to reveal the presence of different flexibility patterns governed by the torsional angles along the polymer chain which, in the interacting fluctuating environment, control the broadening of the spectral observables. We identify the origin of the homogeneous and inhomogeneous line shape of the simulated optical signals. This is paramount to decipher the spectroscopic nature of the ultrafast electron-transfer process occurring in organic photovoltaic (OPV) materials.
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24
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Zhang M, Zhou W, Zhuang B, Zheng Z, Zhang Q, Wang H. Theoretical investigation of electrochromic mechanism in D-A conjugated polymers in visible and infrared bands. RSC Adv 2023; 13:11337-11345. [PMID: 37057261 PMCID: PMC10088488 DOI: 10.1039/d3ra01600e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Accepted: 03/27/2023] [Indexed: 04/15/2023] Open
Abstract
Electrochromic materials have been widely-applied in military camouflage and intelligent materials, in consideration of the multicolor display and infrared absorption. However, most of them have a narrow width of absorption spectra, and the electrochromic mechanism is still not well understood, especially in materials based on a copolymer structure in visible and infrared bands. Therefore, based on the polaron model, in order to enhance polarizability, we designed an "electronic donors-electronic acceptor" (D-A) type π-conjugated electrochromic polymer, which has an abundant color (wavelengths from 450 nm to 750 nm) with voltage range (from -0.2 V to 1.0 V). Employing first-principle calculations, we investigated the electrochromism of the polymer, which has a strong connection with the introduced new molecular orbital in the polaron (or cation), comparing with those in the neutral molecule. This study addressed the underlying mechanism for the electrochromic phenomenon and the behavior of the cation. It indicated the polaron molecular orbitals provide the photon absorption, whose energies are in the visible range and result in the electrochromic abundant color. In this work, we provide a molecular design for the adjustment of visible and infrared band absorption, which could have broad application in multicolor and infrared electrochromic materials.
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Affiliation(s)
- Meiyu Zhang
- Faculty of Materials and Manufacturing, Faculty of Information Technology, Beijing University of Technology Beijing China
| | - Wencai Zhou
- Faculty of Materials and Manufacturing, Faculty of Information Technology, Beijing University of Technology Beijing China
| | - Biying Zhuang
- Faculty of Materials and Manufacturing, Faculty of Information Technology, Beijing University of Technology Beijing China
| | - Zilong Zheng
- Faculty of Materials and Manufacturing, Faculty of Information Technology, Beijing University of Technology Beijing China
| | - Qianqian Zhang
- Faculty of Materials and Manufacturing, Faculty of Information Technology, Beijing University of Technology Beijing China
| | - Hao Wang
- Faculty of Materials and Manufacturing, Faculty of Information Technology, Beijing University of Technology Beijing China
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25
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Wei Z, Chen Y, Wang J, Yang T, Zhao Z, Zhu S. De Novo Synthesis of α-Oligo(arylfuran)s and Its Application in OLED as Hole-Transporting Material. Chemistry 2023; 29:e202203444. [PMID: 36517415 DOI: 10.1002/chem.202203444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/14/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022]
Abstract
Tuning the photophysical properties of π-conjugated oligomers by functionalization of skeleton, to achieve an optically and electronically advantageous building block for organic semiconductor materials is a vital yet challenging task. In this work, a series of structurally well-defined polyaryl-functionalized α-oligofurans, in which aryl groups are introduced precisely into each of the furan units, are rapidly and efficiently synthesized by de novo metal-free synthesis of α-bi(arylfuran) monomers for the first time. This new synthetic strategy nicely circumvents the cumbersome substituent introduction process in the later stage by the preinstallation of the desired aryl groups in the starting material. The characterization of α-oligo(arylfuran)s demonstrates that photoelectric properties of coplanar α-oligo(arylfuran)s can be tuned through varying aryl groups with different electrical properties. These novel α-oligo(arylfuran)s have good hole transport capacity and can function as hole-transporting layers in organic light-emitting diodes, which is indicative of significant breakthrough in the application of α-oligofurans materials in OLEDs. And our findings offer an avenue for the ingenious use of α-oligo(arylfuran)s as p-type organic semiconductors for OLEDs.
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Affiliation(s)
- Zhuwen Wei
- Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, 510640, Guangzhou, P. R. China
| | - Yang Chen
- Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, 510640, Guangzhou, P. R. China
| | - Jianghui Wang
- State Key Laboratory of Luminescent Materials and, Devices, Guangdong Provincial Key Laboratory of, Luminescence from Molecular Aggregates, South China University of Technology, 510640, Guangzhou, P. R. China
| | - Tao Yang
- State Key Laboratory of Luminescent Materials and, Devices, Guangdong Provincial Key Laboratory of, Luminescence from Molecular Aggregates, South China University of Technology, 510640, Guangzhou, P. R. China
| | - Zujin Zhao
- State Key Laboratory of Luminescent Materials and, Devices, Guangdong Provincial Key Laboratory of, Luminescence from Molecular Aggregates, South China University of Technology, 510640, Guangzhou, P. R. China
| | - Shifa Zhu
- Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, 510640, Guangzhou, P. R. China
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26
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Ghosh R, Paesani F. Connecting the dots for fundamental understanding of structure-photophysics-property relationships of COFs, MOFs, and perovskites using a Multiparticle Holstein Formalism. Chem Sci 2023; 14:1040-1064. [PMID: 36756323 PMCID: PMC9891456 DOI: 10.1039/d2sc03793a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 11/09/2022] [Indexed: 11/17/2022] Open
Abstract
Photoactive organic and hybrid organic-inorganic materials such as conjugated polymers, covalent organic frameworks (COFs), metal-organic frameworks (MOFs), and layered perovskites, display intriguing photophysical signatures upon interaction with light. Elucidating structure-photophysics-property relationships across a broad range of functional materials is nontrivial and requires our fundamental understanding of the intricate interplay among excitons (electron-hole pair), polarons (charges), bipolarons, phonons (vibrations), inter-layer stacking interactions, and different forms of structural and conformational defects. In parallel with electronic structure modeling and data-driven science that are actively pursued to successfully accelerate materials discovery, an accurate, computationally inexpensive, and physically-motivated theoretical model, which consistently makes quantitative connections with conceptually complicated experimental observations, is equally important. Within this context, the first part of this perspective highlights a unified theoretical framework in which the electronic coupling as well as the local coupling between the electronic and nuclear degrees of freedom can be efficiently described for a broad range of quasiparticles with similarly structured Holstein-style vibronic Hamiltonians. The second part of this perspective discusses excitonic and polaronic photophysical signatures in polymers, COFs, MOFs, and perovskites, and attempts to bridge the gap between different research fields using a common theoretical construct - the Multiparticle Holstein Formalism. We envision that the synergistic integration of state-of-the-art computational approaches with the Multiparticle Holstein Formalism will help identify and establish new, transformative design strategies that will guide the synthesis and characterization of next-generation energy materials optimized for a broad range of optoelectronic, spintronic, and photonic applications.
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Affiliation(s)
- Raja Ghosh
- Department of Chemistry and Biochemistry, University of California La Jolla San Diego California 92093 USA
| | - Francesco Paesani
- Department of Chemistry and Biochemistry, University of California La Jolla San Diego California 92093 USA
- San Diego Supercomputer Center, University of California La Jolla San Diego California 92093 USA
- Materials Science and Engineering, University of California La Jolla San Diego California 92093 USA
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27
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Roy P, Anandan GT, Nayak N, Kumar A, Dasgupta J. Raman Snapshots of Side-Chain Dependent Polaron Dynamics in PolyThiophene Films. J Phys Chem B 2023; 127:567-576. [PMID: 36599044 DOI: 10.1021/acs.jpcb.2c06185] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Photogenerated polarons in π-conjugated polymers are the precursors to free charges at donor-acceptor interfaces. Unraveling the relationship between film morphology and polaron formation is conjectured to enable efficient charge generation in organic photovoltaic devices. However, it has been challenging to track the ultrafast dynamics of polarons selectively and thus evaluate the molecular coordinates that drive charge generation in films. Using a combination of broadband femtosecond transient absorption and resonance-selective femtosecond stimulated Raman spectroscopy, here, we investigate the polaron generation dynamics exclusively in traditional crystalline poly(3-hexylthiophene) (P3HT) and its amorphous side-chain variant poly(3-(2-ethylhexyl)thiophene-2,5-diyl) (P3EHT) films. The transient Raman data unequivocally provides evidence for an initial delocalization of the polaronic states via thiophene backbone planarization in ∼100 fs while capturing the subsequent morphology-dependent cooling dynamics in a few picoseconds. Our work highlights the structural significance of crystalline morphology in generating hot-charges and thereby emphasizes the importance of side-chain engineering in designing highly efficient conjugated polymer films for hot-carrier photovoltaic devices.
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Affiliation(s)
- Palas Roy
- Department of Chemical Sciences, Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400005, India
| | - Gokul T Anandan
- Department of Chemical Sciences, Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400005, India
| | - Nagaraj Nayak
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Anil Kumar
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Jyotishman Dasgupta
- Department of Chemical Sciences, Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400005, India
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28
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Wang K, Ma J, Ma H. Characterizing the excited states of large photoactive systems by exciton models. J CHIN CHEM SOC-TAIP 2022. [DOI: 10.1002/jccs.202200381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Ke Wang
- School of Chemistry and Chemical Engineering Nanjing University Nanjing China
| | - Jing Ma
- School of Chemistry and Chemical Engineering Nanjing University Nanjing China
| | - Haibo Ma
- School of Chemistry and Chemical Engineering Nanjing University Nanjing China
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29
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Taher-Ghahramani F, Zheng F, Eisfeld A. Gaussian process regression for absorption spectra analysis of molecular dimers. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 275:121091. [PMID: 35306303 DOI: 10.1016/j.saa.2022.121091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 02/05/2022] [Accepted: 02/25/2022] [Indexed: 06/14/2023]
Abstract
A common task is the determination of system parameters from spectroscopy, where one compares the experimental spectrum with calculated spectra, that depend on the desired parameters. Here we discuss an approach based on a machine learning technique, where the parameters for the numerical calculations are chosen from Gaussian Process Regression (GPR). This approach does not only quickly converge to an optimal parameter set, but in addition provides information about the complete parameter space, which allows for example to identify extended parameter regions where numerical spectra are consistent with the experimental one. We consider as example dimers of organic molecules and aim at extracting in particular the interaction between the monomers, and their mutual orientation. We find that indeed the GPR gives reliable results which are in agreement with direct calculations of these parameters using quantum chemical methods.
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Affiliation(s)
- Farhad Taher-Ghahramani
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Str 38, Dresden, Germany.
| | - Fulu Zheng
- Bremen Center for Computational Materials Science, University of Bremen, Am Fallturm 1, 28359 Bremen, Germany.
| | - Alexander Eisfeld
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Str 38, Dresden, Germany.
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30
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Jacobs IE, Lin Y, Huang Y, Ren X, Simatos D, Chen C, Tjhe D, Statz M, Lai L, Finn PA, Neal WG, D'Avino G, Lemaur V, Fratini S, Beljonne D, Strzalka J, Nielsen CB, Barlow S, Marder SR, McCulloch I, Sirringhaus H. High-Efficiency Ion-Exchange Doping of Conducting Polymers. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2102988. [PMID: 34418878 DOI: 10.1002/adma.202102988] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 06/28/2021] [Indexed: 06/13/2023]
Abstract
Molecular doping-the use of redox-active small molecules as dopants for organic semiconductors-has seen a surge in research interest driven by emerging applications in sensing, bioelectronics, and thermoelectrics. However, molecular doping carries with it several intrinsic problems stemming directly from the redox-active character of these materials. A recent breakthrough was a doping technique based on ion-exchange, which separates the redox and charge compensation steps of the doping process. Here, the equilibrium and kinetics of ion exchange doping in a model system, poly(2,5-bis(3-alkylthiophen-2-yl)thieno(3,2-b)thiophene) (PBTTT) doped with FeCl3 and an ionic liquid, is studied, reaching conductivities in excess of 1000 S cm-1 and ion exchange efficiencies above 99%. Several factors that enable such high performance, including the choice of acetonitrile as the doping solvent, which largely eliminates electrolyte association effects and dramatically increases the doping strength of FeCl3 , are demonstrated. In this high ion exchange efficiency regime, a simple connection between electrochemical doping and ion exchange is illustrated, and it is shown that the performance and stability of highly doped PBTTT is ultimately limited by intrinsically poor stability at high redox potential.
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Affiliation(s)
- Ian E Jacobs
- Optoelectronics Group, Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Yue Lin
- Optoelectronics Group, Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Yuxuan Huang
- Optoelectronics Group, Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Xinglong Ren
- Optoelectronics Group, Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Dimitrios Simatos
- Optoelectronics Group, Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, UK
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Chen Chen
- Optoelectronics Group, Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Dion Tjhe
- Optoelectronics Group, Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Martin Statz
- Optoelectronics Group, Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Lianglun Lai
- Optoelectronics Group, Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Peter A Finn
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - William G Neal
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Gabriele D'Avino
- Grenoble Alpes University, CNRS, Grenoble INP, Institut Néel, 25 rue des Martyrs, Grenoble, 38042, France
| | - Vincent Lemaur
- Laboratory for Chemistry of Novel Materials, University of Mons, Mons, B-7000, Belgium
| | - Simone Fratini
- Grenoble Alpes University, CNRS, Grenoble INP, Institut Néel, 25 rue des Martyrs, Grenoble, 38042, France
| | - David Beljonne
- Laboratory for Chemistry of Novel Materials, University of Mons, Mons, B-7000, Belgium
| | - Joseph Strzalka
- X-Ray Science Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Christian B Nielsen
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Stephen Barlow
- School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Seth R Marder
- School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Iain McCulloch
- KAUST Solar Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955, Saudi Arabia
- Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Henning Sirringhaus
- Optoelectronics Group, Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, UK
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31
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Sawada R, Maeda T, Oda Y, Yagi S, Karunakaran V, Fujiwara H, Ajayaghosh A. Synthesis, Photophysical and Electrochemical Properties of Bis-Squaraine Dyes Fused on Isomeric Benzodipyrrole Central Units. Chem Asian J 2022; 17:e202200227. [PMID: 35333439 DOI: 10.1002/asia.202200227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 03/25/2022] [Indexed: 11/10/2022]
Abstract
Exciton interactions are not only observed in assembled molecules but also in compounds with multiple chromophores referred to as superchromophores. We have developed isomeric bis-squaraine dyes as superchromophores in which two squaraine chromophores are fused onto the isomeric benzodipyrrole skeleton so as to regulate conformations and to reduce distances between two chromophores. The dyes with benzo[1,2-b:3,4-b']dipyrrole and benzo[1,2-b:5,4-b']dipyrrole moieties exhibited split electronic absorption originated from the intramolecular exciton interaction. The intensity of the split absorption bands varies in correlation with the orientation of chromophores. The isomeric dye with benzo[1,2-b:4,5-b']dipyrrole moiety exhibited a near-infrared absorption associated with the resonance throughout two chromophores. Their electrochemical and spectroelectrochemical properties are distinct from those of monomeric dyes owing to electronic interactions between the two chromophores. Thus, the structural isomerism of the central skeleton significantly affects their optical properties as well as their electrochemical properties.
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Affiliation(s)
- Ryuhei Sawada
- Graduate School of Engineering, Osaka Prefecture University, Department of Applied Chemistry, Gakuen-cho, 599-8531, Sakai, JAPAN
| | - Takeshi Maeda
- Osaka Prefecture Univesity, Department of Applied Chemistry, Gakuen-cho, 599-8531, Sakai, JAPAN
| | - Yuya Oda
- Graduate School of Engineering, Department of Applied Chemistry, JAPAN
| | - Shigeyuki Yagi
- Graduate School of Engineering, Department of Applied Chemistry, Gakuen-cho, 599-8531, Sakai, JAPAN
| | - Venugopal Karunakaran
- NIIST-CSIR: National Institute for Interdisciplinary Science and Technology CSIR, Photosciences and Photonics Section, Chemical Sciences and Technology Division, 695 019, Thiruvananthapuram, INDIA
| | - Hideki Fujiwara
- Graduate School of Science, Department of Chemistry, Gakuen-cho, 599-8531, Sakai, JAPAN
| | - Ayyappanpillai Ajayaghosh
- NIIST-CSIR: National Institute for Interdisciplinary Science and Technology CSIR, Chemical Sciences and Technology Division, 695 019, Thiruvananthapuram, INDIA
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32
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Jacobs IE, D’Avino G, Lemaur V, Lin Y, Huang Y, Chen C, Harrelson TF, Wood W, Spalek LJ, Mustafa T, O’Keefe CA, Ren X, Simatos D, Tjhe D, Statz M, Strzalka JW, Lee JK, McCulloch I, Fratini S, Beljonne D, Sirringhaus H. Structural and Dynamic Disorder, Not Ionic Trapping, Controls Charge Transport in Highly Doped Conducting Polymers. J Am Chem Soc 2022; 144:3005-3019. [PMID: 35157800 PMCID: PMC8874922 DOI: 10.1021/jacs.1c10651] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Indexed: 01/23/2023]
Abstract
Doped organic semiconductors are critical to emerging device applications, including thermoelectrics, bioelectronics, and neuromorphic computing devices. It is commonly assumed that low conductivities in these materials result primarily from charge trapping by the Coulomb potentials of the dopant counterions. Here, we present a combined experimental and theoretical study rebutting this belief. Using a newly developed doping technique based on ion exchange, we prepare highly doped films with several counterions of varying size and shape and characterize their carrier density, electrical conductivity, and paracrystalline disorder. In this uniquely large data set composed of several classes of high-mobility conjugated polymers, each doped with at least five different ions, we find electrical conductivity to be strongly correlated with paracrystalline disorder but poorly correlated with ionic size, suggesting that Coulomb traps do not limit transport. A general model for interacting electrons in highly doped polymers is proposed and carefully parametrized against atomistic calculations, enabling the calculation of electrical conductivity within the framework of transient localization theory. Theoretical calculations are in excellent agreement with experimental data, providing insights into the disorder-limited nature of charge transport and suggesting new strategies to further improve conductivities.
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Affiliation(s)
- Ian E. Jacobs
- Optoelectronics
Group, Cavendish Laboratory, University
of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, U.K.
| | - Gabriele D’Avino
- Grenoble
Alpes University, CNRS, Grenoble INP, Institut
Néel, 25 rue des Martyrs, 38042 Grenoble, France
| | - Vincent Lemaur
- Laboratory
for Chemistry of Novel Materials, University
of Mons, Mons B-7000, Belgium
| | - Yue Lin
- Optoelectronics
Group, Cavendish Laboratory, University
of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, U.K.
| | - Yuxuan Huang
- Optoelectronics
Group, Cavendish Laboratory, University
of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, U.K.
| | - Chen Chen
- Optoelectronics
Group, Cavendish Laboratory, University
of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, U.K.
| | - Thomas F. Harrelson
- Molecular
Foundry, Lawrence Berkeley National Laboratory, One Cyclotron Road Building 67, Berkeley, California 94720, United States
| | - William Wood
- Optoelectronics
Group, Cavendish Laboratory, University
of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, U.K.
| | - Leszek J. Spalek
- Optoelectronics
Group, Cavendish Laboratory, University
of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, U.K.
| | - Tarig Mustafa
- Optoelectronics
Group, Cavendish Laboratory, University
of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, U.K.
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.
| | - Christopher A. O’Keefe
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.
| | - Xinglong Ren
- Optoelectronics
Group, Cavendish Laboratory, University
of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, U.K.
| | - Dimitrios Simatos
- Optoelectronics
Group, Cavendish Laboratory, University
of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, U.K.
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.
| | - Dion Tjhe
- Optoelectronics
Group, Cavendish Laboratory, University
of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, U.K.
| | - Martin Statz
- Optoelectronics
Group, Cavendish Laboratory, University
of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, U.K.
| | - Joseph W. Strzalka
- X-Ray
Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Jin-Kyun Lee
- Department
of Polymer Science & Engineering, Inha
University, Incheon 402-751, South Korea
| | - Iain McCulloch
- Department
of Chemistry, University of Oxford, Oxford OX1 3TA, U.K.
- KAUST
Solar Center, Physical Sciences and Engineering Division (PSE), Materials
Science and Engineering Program (MSE), King
Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Simone Fratini
- Grenoble
Alpes University, CNRS, Grenoble INP, Institut
Néel, 25 rue des Martyrs, 38042 Grenoble, France
| | - David Beljonne
- Laboratory
for Chemistry of Novel Materials, University
of Mons, Mons B-7000, Belgium
| | - Henning Sirringhaus
- Optoelectronics
Group, Cavendish Laboratory, University
of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, U.K.
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33
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Wu R, Matta M, Paulsen BD, Rivnay J. Operando Characterization of Organic Mixed Ionic/Electronic Conducting Materials. Chem Rev 2022; 122:4493-4551. [PMID: 35026108 DOI: 10.1021/acs.chemrev.1c00597] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Operando characterization plays an important role in revealing the structure-property relationships of organic mixed ionic/electronic conductors (OMIECs), enabling the direct observation of dynamic changes during device operation and thus guiding the development of new materials. This review focuses on the application of different operando characterization techniques in the study of OMIECs, highlighting the time-dependent and bias-dependent structure, composition, and morphology information extracted from these techniques. We first illustrate the needs, requirements, and challenges of operando characterization then provide an overview of relevant experimental techniques, including spectroscopy, scattering, microbalance, microprobe, and electron microscopy. We also compare different in silico methods and discuss the interplay of these computational methods with experimental techniques. Finally, we provide an outlook on the future development of operando for OMIEC-based devices and look toward multimodal operando techniques for more comprehensive and accurate description of OMIECs.
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Affiliation(s)
- Ruiheng Wu
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Micaela Matta
- Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, United Kingdom
| | - Bryan D Paulsen
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Jonathan Rivnay
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208, United States.,Simpson Querrey Institute, Northwestern University, Chicago, Illinois 60611, United States
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34
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Thickness Dependence of Doping Level in Conducting Polymer Films: the Optical Contrast Optimization in Electrochromism as a Case Study. CHINESE J CHEM 2021. [DOI: 10.1002/cjoc.202100754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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35
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Livshits MY, Yang J, Maghsoodi F, Scheberl A, Greer SM, Khalil MI, Strach E, Brown D, Stein BW, Reimhult E, Rack JJ, Chi E, Whitten DG. Understanding the Photochemical Properties of Polythiophene Polyelectrolyte Soft Aggregates with Sodium Dodecyl Sulfate for Antimicrobial Activity. ACS APPLIED MATERIALS & INTERFACES 2021; 13:55953-55965. [PMID: 34788015 DOI: 10.1021/acsami.1c18553] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The threat of antibiotic-resistant bacteria is an ever-increasing problem in public health. In this report, we examine the photochemical properties with a proof-of-principle biocidal assay for a novel series of regio-regular imidazolium derivative poly-(3-hexylthiophene)/sodium dodecyl sulfate (P3HT-Im/SDS) materials from ultrafast sub-ps dynamics to μs generation of reactive oxygen species (ROS) and 30 min biocidal reactivity with Escherichia coli (E. coli). This broad series encompassing pure P3HT-Im to cationic, neutral, and anionic P3HT-Im/SDS materials are all interrogated by a variety of techniques to characterize the physical material structure, electronic structure, and antimicrobial activity. Our results show that SDS complexation with P3HT-Im results in aggregate materials with reduced ROS generation and light-induced anti-microbial activity. However, our characterization reveals that the presence of non-aggregated or lightly SDS-covered polymer segments is still capable of ROS generation. Full encapsulation of the P3HT-Im polymer completely deactivates the light killing pathway. High SDS concentrations, near and above critical micelle concentration, further deactivate all anti-microbial activity (light and dark) even though the P3HT-Im regains its electronic properties to generate ROS.
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Affiliation(s)
- Maksim Y Livshits
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Jianzhong Yang
- Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico 87131, United States
- Department of Chemical and Biological Engineering, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Fahimeh Maghsoodi
- Nanoscience and Microsystems Engineering Graduate Program, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Andrea Scheberl
- Department of Nanobiotechnology, University of Natural Resources and Life Sciences, Vienna (BOKU Wien) Muthgasse 11-II, Vienna A-1190, Austria
| | - Samuel M Greer
- Los Alamos National Laboratory (LANL), Los Alamos, New Mexico 87545, United States
| | - Mohammed I Khalil
- Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico 87131, United States
- Department of Chemical and Biological Engineering, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Edward Strach
- Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico 87131, United States
- Department of Chemical and Biological Engineering, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Dylan Brown
- Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico 87131, United States
- Department of Chemical and Biological Engineering, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Benjamin W Stein
- Los Alamos National Laboratory (LANL), Los Alamos, New Mexico 87545, United States
| | - Erik Reimhult
- Department of Nanobiotechnology, University of Natural Resources and Life Sciences, Vienna (BOKU Wien) Muthgasse 11-II, Vienna A-1190, Austria
| | - Jeffrey J Rack
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Eva Chi
- Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico 87131, United States
- Department of Chemical and Biological Engineering, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - David G Whitten
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
- Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico 87131, United States
- Department of Chemical and Biological Engineering, University of New Mexico, Albuquerque, New Mexico 87131, United States
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36
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Liu YH, Wang K, Ma HB. Evaluating first-order molecular properties of delocalized ionic or excited states in molecular aggregates by renormalized excitonic method. CHINESE J CHEM PHYS 2021. [DOI: 10.1063/1674-0068/cjcp2108133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Yun-hao Liu
- School of Chemistry and Chemical Engineering, Jiangsu Key Laboratory of Vehicle Emissions Control, Nanjing University, Nanjing 210023, China
| | - Ke Wang
- School of Chemistry and Chemical Engineering, Jiangsu Key Laboratory of Vehicle Emissions Control, Nanjing University, Nanjing 210023, China
| | - Hai-bo Ma
- School of Chemistry and Chemical Engineering, Jiangsu Key Laboratory of Vehicle Emissions Control, Nanjing University, Nanjing 210023, China
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37
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Zhu H, Xiao S, Tu W, Yan S, He T, Zhu X, Yao Y, Zhou Y, Zou Z. In Situ Determination of Polaron-Mediated Ultrafast Electron Trapping in Rutile TiO 2 Nanorod Photoanodes. J Phys Chem Lett 2021; 12:10815-10822. [PMID: 34726410 DOI: 10.1021/acs.jpclett.1c03113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Mechanistic understanding of the photogenerated charge carrier dynamics in modified semiconductor photoanodes is vital for the efficient enhancement of photoelectrochemical (PEC) water splitting. Here, an in situ femtosecond (fs)-transient absorption spectroscopy (TAS) assisted spectroelectrochemistry technique is used to probe the behavior of charge carriers in rutile TiO2 nanorod photoanodes under the different applied potentials and different density of surface polaron states that can be tuned via direct electrochemical protonation. We interpreted the background absorption with long-time decay in terms of polaron-mediated ultrafast electron trapping. The depleted surface polaron states on rutile TiO2 nanorods can trap photogenerated electrons and endow them with a long lifetime; thus, increasing the polaron state density can enhance the charge separation efficiency and the photocurrent density of the TiO2 nanorod electrode.
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Affiliation(s)
- Heng Zhu
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong 518172, P.R. China
- University of Science and Technology of China, Hefei, Anhui 230026, P.R. China
| | - Shuyu Xiao
- College of Physics and Optoelectronic Engineering, Shenzhen University Shenzhen 518060, P.R. China
| | - Wenguang Tu
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong 518172, P.R. China
| | - Shicheng Yan
- College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu 210093, P.R. China
| | - Tingchao He
- College of Physics and Optoelectronic Engineering, Shenzhen University Shenzhen 518060, P.R. China
| | - Xi Zhu
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong 518172, P.R. China
| | - Yingfang Yao
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong 518172, P.R. China
- College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu 210093, P.R. China
| | - Yong Zhou
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong 518172, P.R. China
- Jiangsu Key Laboratory for Nano Technology, National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, School of Physics, Nanjing University, Nanjing, Jiangsu 210093, P.R. China
| | - Zhigang Zou
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong 518172, P.R. China
- Jiangsu Key Laboratory for Nano Technology, National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, School of Physics, Nanjing University, Nanjing, Jiangsu 210093, P.R. China
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38
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Kim T, Oh S, Choudhry U, Meinhart CD, Chabinyc ML, Liao B. Transient Strain-Induced Electronic Structure Modulation in a Semiconducting Polymer Imaged by Scanning Ultrafast Electron Microscopy. NANO LETTERS 2021; 21:9146-9152. [PMID: 34672604 DOI: 10.1021/acs.nanolett.1c02963] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Understanding the optoelectronic properties of semiconducting polymers under external strain is essential for their applications in flexible devices. Although prior studies have highlighted the impact of static and macroscopic strains, assessing the effect of a local transient deformation before structural relaxation occurs remains challenging. Here, we employ scanning ultrafast electron microscopy (SUEM) to image the dynamics of a photoinduced transient strain in the semiconducting polymer poly(3-hexylthiophene) (P3HT). We observe that the photoinduced SUEM contrast, corresponding to the local change of secondary electron emission, exhibits an unusual ring-shaped profile. We attribute the observation to the electronic structure modulation of P3HT caused by a photoinduced strain field owing to its low modulus and strong electron-lattice coupling, supported by a finite-element analysis. Our work provides insights into tailoring optoelectronic properties using transient mechanical deformation in semiconducting polymers and demonstrates the versatility of SUEM to study photophysical processes in diverse materials.
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Affiliation(s)
- Taeyong Kim
- Department of Mechanical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Saejin Oh
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Usama Choudhry
- Department of Mechanical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Carl D Meinhart
- Department of Mechanical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Michael L Chabinyc
- Materials Department, University of California, Santa Barbara, California 93106, United States
| | - Bolin Liao
- Department of Mechanical Engineering, University of California, Santa Barbara, California 93106, United States
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39
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Ghosh R, Paesani F. Topology-Mediated Enhanced Polaron Coherence in Covalent Organic Frameworks. J Phys Chem Lett 2021; 12:9442-9448. [PMID: 34554754 DOI: 10.1021/acs.jpclett.1c02454] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We employ the Holstein model for polarons to investigate the relationship among defects, topology, Coulomb trapping, and polaron delocalization in covalent organic frameworks (COFs). We find that intrasheet topological connectivity and π-column density can override disorder-induced deep traps and significantly enhance polaron migration by several orders of magnitude in good agreement with recent experimental observations. The combination of percolation networks and micropores makes trigonal COFs ideally suited for charge transport followed by kagome/tetragonal and hexagonal structures. By comparing the polaron spectral signatures and coherence numbers of large three-dimensional frameworks having a maximum of 180 coupled chromophores, we show that controlling nanoscale defects and the location of the counteranion is critical for the design of new COF-based materials yielding higher mobilities. Our analysis establishes design strategies for enhanced conductivity in COFs that can be readily generalized to other classes of conductive materials such as metal-organic frameworks and perovskites.
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Affiliation(s)
- Raja Ghosh
- Department of Chemistry and Biochemistry, ‡Materials Science and Engineering, and §San Diego Supercomputer Center, University of California, San Diego, La Jolla, California 92093, United States
| | - Francesco Paesani
- Department of Chemistry and Biochemistry, ‡Materials Science and Engineering, and §San Diego Supercomputer Center, University of California, San Diego, La Jolla, California 92093, United States
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40
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Prodhan S, Giannini S, Wang L, Beljonne D. Long-Range Interactions Boost Singlet Exciton Diffusion in Nanofibers of π-Extended Polymer Chains. J Phys Chem Lett 2021; 12:8188-8193. [PMID: 34415752 DOI: 10.1021/acs.jpclett.1c02275] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Raising the distance covered by singlet excitons during their lifetimes to values maximizing light absorption (a few hundred nm) would solve the exciton diffusion bottleneck issue and lift the constraint for fine (∼10 nm) phase segregation in bulk heterojunction organic solar cells. In that context, the recent report of highly ordered conjugated polymer nanofibers featuring singlet exciton diffusion length, LD, in excess of 300 nm is both appealing and intriguing [Jin, X.; et al. Science 2018, 360 (6391), 897-900]. Here, on the basis of nonadiabatic molecular dynamics simulations, we demonstrate that singlet exciton diffusion in poly(3-hexylthiophene) (P3HT) fibers is highly sensitive to the interplay between delocalization along the polymer chains and long-range interactions along the stacks. Remarkably, the diffusion coefficient is predicted to rocket by 3 orders of magnitude when going beyond nearest-neighbor intermolecular interactions in fibers of extended (30-mer) polymer chains and to be resilient to interchain energetic and positional disorders.
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Affiliation(s)
- Suryoday Prodhan
- Laboratory for Chemistry of Novel Materials, University of Mons, Mons 7000, Belgium
| | - Samuele Giannini
- Laboratory for Chemistry of Novel Materials, University of Mons, Mons 7000, Belgium
| | - Linjun Wang
- Key Laboratory of Excited-State Materials of Zhejiang Province, Department of Chemistry, Zhejiang University, Hangzhou 310027, China
| | - David Beljonne
- Laboratory for Chemistry of Novel Materials, University of Mons, Mons 7000, Belgium
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41
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Seibt J, Kühn O. Strong Exciton-Vibrational Coupling in Molecular Assemblies. Dynamics Using the Polaron Transformation in HEOM Space. J Phys Chem A 2021; 125:7052-7065. [PMID: 34353023 DOI: 10.1021/acs.jpca.1c02684] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In Frenkel exciton dynamics of aggregated molecules, the polaron transformation (PT) technique leads to decoupling of diagonal elements in the subspace of excited electronic states from vibrations. In this article we describe for the first time how PT becomes applicable in the framework of the "Hierarchical Equations of Motion" (HEOM) approach for treatment of open quantum systems. We extend the concept of formulating operators in HEOM space by deriving hierarchical equations of PT which lead to a shift in the excited state potential energy surface to compensate its displacement. While the assumption of thermal equilibration of the vibrational oscillators, introduced by PT, results in a stationary state in a monomer, in a dimer under the same assumption nonequilibrium dynamics appears because of the interplay of the transfer process and vibrational equilibration. Both vertical transitions generating a vibrationally hot state and initially equilibrated vibrational oscillators evolve toward the same stationary asymptotic state associated with polaron formation. The effect of PT on the dynamics of this process depends on initial excitation and basis representation of the electronic system. The developed approach facilitates a generic formulation of quantum master equations involving perturbative treatment of polaron dynamics.
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Affiliation(s)
- Joachim Seibt
- Institute of Physics, University of Rostock, Albert-Einstein-Str. 23-24, 18059 Rostock, Germany.,Institute for Theoretical Physics, Johannes Kepler University Linz, Altenberger Str. 69, 4040 Linz, Austria
| | - Oliver Kühn
- Institute of Physics, University of Rostock, Albert-Einstein-Str. 23-24, 18059 Rostock, Germany
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42
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Diez-Cabanes V, Monari A, Pastore M. Competition between the Photothermal Effect and Emission in Potential Phototherapy Agents. J Phys Chem B 2021; 125:8733-8741. [PMID: 34323496 DOI: 10.1021/acs.jpcb.1c03977] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Planar donor-acceptor-donor (D-A-D) organic molecules have been highlighted as promising photothermal agents due to their good light-to-heat conversion ratio, easy degradation, and chemical tunability. Very recently, it has been demonstrated that their photothermal conversion can be boosted by appending rather long alkyl chains. Despite this behavior being tentatively associated with the population of a nonradiative twisted intramolecular charge transfer (TICT) state driven by an intramolecular motion, the precise mechanisms and the role played by the environment, and most notably aggregation, still remain elusive. In this context, we carried out a series of time-dependent density functional theory (TD-DFT) calculations combined with molecular dynamics (MD) simulations to achieve a realistic description of the isolated and aggregated systems. Our theoretical models unambiguously evidence that the population of CT states is very unlikely in both cases, whereas the light-triggered heat dissipation can be ascribed to the activation of specific vibrational degrees of freedom related to the relative motion of the peripheral chains. Overall, our results clearly corroborate the active role played by the alkyl substituents in the photothermal conversion through vibrational motion, while breaking from the conventional picture, which invokes the formation of dark TICT states in loosely packed aggregates.
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Affiliation(s)
- Valentin Diez-Cabanes
- Université de Lorraine & CNRS, Laboratoire de Physique et Chimie Théoriques (LPCT), UMR 7019, F-54000 Nancy, France
| | - Antonio Monari
- Université de Lorraine & CNRS, Laboratoire de Physique et Chimie Théoriques (LPCT), UMR 7019, F-54000 Nancy, France
| | - Mariachiara Pastore
- Université de Lorraine & CNRS, Laboratoire de Physique et Chimie Théoriques (LPCT), UMR 7019, F-54000 Nancy, France
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Vasilchenko V, Levchenko S, Perebeinos V, Zhugayevych A. Small Polarons in Two-Dimensional Pnictogens: A First-Principles Study. J Phys Chem Lett 2021; 12:4674-4680. [PMID: 33979171 DOI: 10.1021/acs.jpclett.1c00929] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We report the first-principles study of small polarons in the most stable two-dimensional pnictogen allotropes: blue and black phosphorene and arsenene. While both cations and anions of small hydrogen-passivated clusters show charge localization and local lattice distortions, only the hole polaron in the blue allotrope is stable in the infinite size cluster limit. The adiabatic polaron relaxation energy is found to be 0.1 eV for phosphorene and 0.15 eV for arsenene. The polaron is localized on lone-pair orbitals with half of the extra charge distributed among 13 atoms. In the blue phosphorene, these orbitals form the valence band's top with a relatively flat band dispersion. However, in the black phosphorene, lone-pair orbitals hybridize with bonding orbitals, which explains the difference in hole localization strength between the two topologically equivalent allotropes. The polaron's adiabatic barriers for motion are small compared to the most strongly coupled phonon frequency, implying the polaron barrierless motion.
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Affiliation(s)
| | - Sergey Levchenko
- Skolkovo Institute of Science and Technology, Moscow 143026, Russia
| | - Vasili Perebeinos
- Department of Electrical Engineering, University at Buffalo, Buffalo, New York 14260, United States
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Ghosh R, Paesani F. Unraveling the effect of defects, domain size, and chemical doping on photophysics and charge transport in covalent organic frameworks. Chem Sci 2021; 12:8373-8384. [PMID: 34221318 PMCID: PMC8221171 DOI: 10.1039/d1sc01262b] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 05/12/2021] [Indexed: 11/21/2022] Open
Abstract
Understanding the underlying physical mechanisms that govern charge transport in two-dimensional (2D) covalent organic frameworks (COFs) will facilitate the development of novel COF-based devices for optoelectronic and thermoelectric applications. In this context, the low-energy mid-infrared absorption contains valuable information about the structure-property relationships and the extent of intra- and inter-framework "hole" polaron delocalization in doped and undoped polymeric materials. In this study, we provide a quantitative characterization of the intricate interplay between electronic defects, domain sizes, pore volumes, chemical dopants, and three dimensional anisotropic charge migration in 2D COFs. We compare our simulations with recent experiments on doped COF films and establish the correlations between polaron coherence, conductivity, and transport signatures. By obtaining the first quantitative agreement with the measured absorption spectra of iodine doped (aza)triangulene-based COF, we highlight the fundamental differences between the underlying microstructure, spectral signatures, and transport physics of polymers and COFs. Our findings provide conclusive evidence of why iodine doped COFs exhibit lower conductivity compared to doped polythiophenes. Finally, we propose new research directions to address existing limitations and improve charge transport in COFs for applications in functional molecular electronic devices.
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Affiliation(s)
- Raja Ghosh
- Department of Chemistry and Biochemistry, University of California San Diego La Jolla California 92093 USA
| | - Francesco Paesani
- Department of Chemistry and Biochemistry, University of California San Diego La Jolla California 92093 USA
- San Diego Supercomputer Center, University of California San Diego La Jolla California 92093 USA
- Materials Science and Engineering, University of California San Diego La Jolla California 92093 USA
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