1
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Myers A, Li Z, Gish MK, Earley JD, Johnson JC, Hermosilla-Palacios MA, Blackburn JL. Ultrafast Charge Transfer Cascade in a Mixed-Dimensionality Nanoscale Trilayer. ACS NANO 2024; 18:8190-8198. [PMID: 38465641 PMCID: PMC10958597 DOI: 10.1021/acsnano.3c12179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 02/23/2024] [Accepted: 03/05/2024] [Indexed: 03/12/2024]
Abstract
Innovation in optoelectronic semiconductor devices is driven by a fundamental understanding of how to move charges and/or excitons (electron-hole pairs) in specified directions for doing useful work, e.g., for making fuels or electricity. The diverse and tunable electronic and optical properties of two-dimensional (2D) transition metal dichalcogenides (TMDCs) and one-dimensional (1D) semiconducting single-walled carbon nanotubes (s-SWCNTs) make them good quantum confined model systems for fundamental studies of charge and exciton transfer across heterointerfaces. Here we demonstrate a mixed-dimensionality 2D/1D/2D MoS2/SWCNT/WSe2 heterotrilayer that enables ultrafast photoinduced exciton dissociation, followed by charge diffusion and slow recombination. Importantly, the heterotrilayer serves to double charge carrier yield relative to a MoS2/SWCNT heterobilayer and also demonstrates the ability of the separated charges to overcome interlayer exciton binding energies to diffuse from one TMDC/SWCNT interface to the other 2D/1D interface, resulting in Coulombically unbound charges. Interestingly, the heterotrilayer also appears to enable efficient hole transfer from SWCNTs to WSe2, which is not observed in the identically prepared WSe2/SWCNT heterobilayer, suggesting that increasing the complexity of nanoscale trilayers may modify dynamic pathways. Our work suggests "mixed-dimensionality" TMDC/SWCNT based heterotrilayers as both interesting model systems for mechanistic studies of carrier dynamics at nanoscale heterointerfaces and for potential applications in advanced optoelectronic systems.
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Affiliation(s)
- Alexis
R. Myers
- National
Renewable Energy Laboratory, Golden, Colorado 80401, United States
- Department
of Chemistry, University of Colorado−Boulder, Boulder, Colorado 80309, United States
| | - Zhaodong Li
- National
Renewable Energy Laboratory, Golden, Colorado 80401, United States
- The
Institute of Technological Sciences, Wuhan
University, Wuhan, Hubei 430072, China
| | - Melissa K. Gish
- National
Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Justin D. Earley
- National
Renewable Energy Laboratory, Golden, Colorado 80401, United States
- Department
of Chemistry, University of Colorado−Boulder, Boulder, Colorado 80309, United States
| | - Justin C. Johnson
- National
Renewable Energy Laboratory, Golden, Colorado 80401, United States
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2
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Dimitriev OP. Dynamics of Excitons in Conjugated Molecules and Organic Semiconductor Systems. Chem Rev 2022; 122:8487-8593. [PMID: 35298145 DOI: 10.1021/acs.chemrev.1c00648] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The exciton, an excited electron-hole pair bound by Coulomb attraction, plays a key role in photophysics of organic molecules and drives practically important phenomena such as photoinduced mechanical motions of a molecule, photochemical conversions, energy transfer, generation of free charge carriers, etc. Its behavior in extended π-conjugated molecules and disordered organic films is very different and very rich compared with exciton behavior in inorganic semiconductor crystals. Due to the high degree of variability of organic systems themselves, the exciton not only exerts changes on molecules that carry it but undergoes its own changes during all phases of its lifetime, that is, birth, conversion and transport, and decay. The goal of this review is to give a systematic and comprehensive view on exciton behavior in π-conjugated molecules and molecular assemblies at all phases of exciton evolution with emphasis on rates typical for this dynamic picture and various consequences of the above dynamics. To uncover the rich variety of exciton behavior, details of exciton formation, exciton transport, exciton energy conversion, direct and reverse intersystem crossing, and radiative and nonradiative decay are considered in different systems, where these processes lead to or are influenced by static and dynamic disorder, charge distribution symmetry breaking, photoinduced reactions, electron and proton transfer, structural rearrangements, exciton coupling with vibrations and intermediate particles, and exciton dissociation and annihilation as well.
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Affiliation(s)
- Oleg P Dimitriev
- V. Lashkaryov Institute of Semiconductor Physics NAS of Ukraine, pr. Nauki 41, Kyiv 03028, Ukraine
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3
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Mirka B, Rice NA, Williams P, Tousignant MN, Boileau NT, Bodnaryk WJ, Fong D, Adronov A, Lessard BH. Excess Polymer in Single-Walled Carbon Nanotube Thin-Film Transistors: Its Removal Prior to Fabrication Is Unnecessary. ACS NANO 2021; 15:8252-8266. [PMID: 33831298 DOI: 10.1021/acsnano.0c08584] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Ultrapure semiconducting single-walled carbon nanotube (sc-SWNT) dispersions produced through conjugated polymer sorting are ideal candidates for the fabrication of solution-processed organic electronic devices on a commercial scale. Protocols for sorting and dispersing ultrapure sc-SWNTs with conjugated polymers for thin-film transistor (TFT) applications have been well refined. Conventional wisdom dictates that removal of excess unbound polymer through filtration or centrifugation is necessary to produce high-performance TFTs. However, this is time-consuming, wasteful, and resource-intensive. In this report, we challenge this paradigm and demonstrate that excess unbound polymer during semiconductor film fabrication is not necessarily detrimental to device performance. Over 1200 TFT devices were fabricated from 30 unique polymer-sorted SWNT dispersions, prepared using two different alternating copolymers. Detailed Raman spectroscopy, x-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) studies of the random-network semiconductor films demonstrated that a simple solvent rinse during TFT fabrication was sufficient to remove unbound polymer from the sc-SWNT films, thus eliminating laborious polymer removal before TFT fabrication. Furthermore, below a threshold polymer concentration, the presence of excess polymer during fabrication did not significantly impede TFT performance. Preeminent performance was achieved for devices prepared from native polymer-sorted SWNT dispersions containing the "original" amount of excess unbound polymer (immediately following enrichment). Lastly, we developed an open-source Machine Learning algorithm to quantitatively analyze AFM images of SWNT films for surface coverage, number of tubes, and tube alignment.
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Affiliation(s)
- Brendan Mirka
- Department of Chemical and Biological Engineering, University of Ottawa, 161 Louis Pasteur, Ottawa, Ontario, Canada K1N 6N5
| | - Nicole A Rice
- Department of Chemical and Biological Engineering, University of Ottawa, 161 Louis Pasteur, Ottawa, Ontario, Canada K1N 6N5
| | - Phillip Williams
- Department of Chemical and Biological Engineering, University of Ottawa, 161 Louis Pasteur, Ottawa, Ontario, Canada K1N 6N5
| | - Mathieu N Tousignant
- Department of Chemical and Biological Engineering, University of Ottawa, 161 Louis Pasteur, Ottawa, Ontario, Canada K1N 6N5
| | - Nicholas T Boileau
- Department of Chemical and Biological Engineering, University of Ottawa, 161 Louis Pasteur, Ottawa, Ontario, Canada K1N 6N5
| | - William J Bodnaryk
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street W, Hamilton, Ontario, Canada L8S 4M1
| | - Darryl Fong
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street W, Hamilton, Ontario, Canada L8S 4M1
| | - Alex Adronov
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street W, Hamilton, Ontario, Canada L8S 4M1
| | - Benoît H Lessard
- Department of Chemical and Biological Engineering, University of Ottawa, 161 Louis Pasteur, Ottawa, Ontario, Canada K1N 6N5
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4
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Kang HS, Peurifoy S, Zhang B, Ferguson AJ, Reid OG, Nuckolls C, Blackburn JL. Linking optical spectra to free charges in donor/acceptor heterojunctions: cross-correlation of transient microwave and optical spectroscopy. MATERIALS HORIZONS 2021; 8:1509-1517. [PMID: 34846459 DOI: 10.1039/d0mh01810d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The primary photoexcited species in excitonic semiconductors is a bound electron-hole pair, or exciton. An important strategy for producing separated electrons and holes in photoexcited excitonic semiconductors is the use of donor/acceptor heterojunctions, but the degree to which the carriers can escape their mutual Coulomb attraction is still debated for many systems. Here, we employ a combined pump-probe ultrafast transient absorption (TA) spectroscopy and time-resolved microwave conductivity (TRMC) study on a suite of model excitonic heterojunctions consisting of mono-chiral semiconducting single-walled carbon nanotube (s-SWCNT) electron donors and small-molecule electron acceptors. Comparison of the charge-separated state dynamics between TA and TRMC photoconductance reveals a quantitative match over the 0.5 microsecond time scale. Charge separation yields derived from TA allow extraction of s-SWCNT hole mobilities of ca. 1.5 cm2 V-1 s-1 (at 9 GHz) by TRMC. The correlation between the techniques conclusively demonstrates that photoinduced charge carriers separated across these heterojunctions do not form bound charge transfer states, but instead form free/mobile charge carriers.
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Affiliation(s)
- Hyun Suk Kang
- National Renewable Energy Laboratory, Golden, CO 80401, USA.
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5
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Lu S, Franklin AD. Printed carbon nanotube thin-film transistors: progress on printable materials and the path to applications. NANOSCALE 2020; 12:23371-23390. [PMID: 33216106 DOI: 10.1039/d0nr06231f] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Printing technologies have attracted significant attention owing to their potential use in the low-cost manufacturing of custom or large-area flexible electronics. Among the many printable electronic materials that have been explored, semiconducting carbon nanotubes (CNTs) have shown increasing promise based on their exceptional electrical and mechanical properties, relative stability in air, and compatibility with several printing techniques to form semiconducting thin films. These attractive attributes make printed CNT thin films promising for applications including, but not limited to, sensors and display backplanes - at the heart of which is electronics' most versatile device: the transistor. In this review, we present a summary of recent advancements in the field of printed carbon nanotube thin-film transistors (CNT-TFTs). In addition to an introduction of different printing techniques, together with their strengths and limitations, we discuss key aspects of ink/material selection and processing of various device components, including the CNT channels, contacts, and gate insulators. It is clear that printed CNT-TFTs are rapidly advancing, but there remain challenges, which are discussed along with current techniques to resolve them and future developments towards practical applications from these devices. There has been interest in low-cost, printable transistors for many years and the CNT-TFTs show great promise for delivering, but will not become a reality without further research advancement.
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Affiliation(s)
- Shiheng Lu
- Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708, USA.
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6
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Lu S, Zheng J, Cardenas JA, Williams NX, Lin YC, Franklin AD. Uniform and Stable Aerosol Jet Printing of Carbon Nanotube Thin-Film Transistors by Ink Temperature Control. ACS APPLIED MATERIALS & INTERFACES 2020; 12:43083-43089. [PMID: 32897054 PMCID: PMC7895321 DOI: 10.1021/acsami.0c12046] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Semiconducting carbon nanotube (CNT) networks exhibit electrical, mechanical, and chemical properties attractive for thin-film applications, and printing allows for scalable and economically favorable fabrication of CNT thin-film transistors (TFTs). However, device-to-device variation of printed CNT-TFTs remains a concern, which largely stems from variations in printed CNT thin-film morphology and resulting properties. In this work, we overcome the challenges associated with printing uniformity and demonstrate an aerosol jet printing process that yields devices exhibiting a hole mobility of μh = 12.5 cm2/V·s with a relative standard deviation as small as 4% (from over 38 devices). The enabling factors of such high uniformity include control of the CNT ink bath temperature during printing, ink formulation with nonvolatile and viscosifying additives, and a thermal treatment for polymer removal. It is discovered that a low CNT ink temperature benefits aerosol jet printing uniformity and stability in both short-term (∼1 min) and long-term (∼1 h) printing settings. These findings shed light on the effect of a commonly overlooked dimension of CNT aerosol jet printing and provide a practical strategy for large-scale, high-consistency realization of CNT-TFTs.
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Affiliation(s)
- Shiheng Lu
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, United States
| | - Joanne Zheng
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, United States
| | - Jorge A Cardenas
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, United States
| | - Nicholas X Williams
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, United States
| | - Yuh-Chen Lin
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, United States
| | - Aaron D Franklin
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, United States
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
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7
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Yang JJ, Li ZW, Liu XY, Fang WH, Cui G. Photoinduced electron transfer from carbon nanotubes to fullerenes: C 60versus C 70. Phys Chem Chem Phys 2020; 22:19542-19548. [PMID: 32844829 DOI: 10.1039/d0cp03622f] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Hybrid carbon materials are found to exhibit novel optoelectronic properties at their interfaces, but the related interfacial carrier dynamics is rarely explored theoretically. In this contribution, we have employed density functional theory (DFT) and DFT-based nonadiabatic dynamics methods to explore photoinduced interfacial electron transfer processes at interfaces between a single-walled carbon nanotube with chiral index (6,5) and C60 or C70 (C60@CNT65 and C70@CNT65). We have found that with low E11 excitation, electron transfer takes place from CNT65 to C60 and C70 in both heterojunctions. This process is ultrafast and completed within about 200 fs, which is consistent with recent experiments. Differently, high E22 excitation does not induce electron injection to C60 in C60@CNT65; instead, "hot" electrons produced within CNT65 will be trapped in its higher conduction band for a while because of slow inter-band relaxation. By contrast, in C70@CNT65, high E22 excitation still can lead to ultrafast electron transfer to C70, but only a comparable amount of electrons are transferred (ca. 30%). Interestingly, electrons either remaining on CNT65 or transferred to C70 are trapped in the higher conduction band for a while, similarly, due to slow inter-band relaxation. The present results could be useful to guide the design of excellent interfaces of mixed-dimensional hybrid carbon materials for various optoelectronic applications.
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Affiliation(s)
- Jia-Jia Yang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
| | - Zi-Wen Li
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
| | - Xiang-Yang Liu
- College of Chemistry and Material Science, Sichuan Normal University, Chengdu 610068, China.
| | - Wei-Hai Fang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
| | - Ganglong Cui
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
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8
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Flach JT, Wang J, Arnold MS, Zanni MT. Providing Time to Transfer: Longer Lifetimes Lead to Improved Energy Transfer in Films of Semiconducting Carbon Nanotubes. J Phys Chem Lett 2020; 11:6016-6024. [PMID: 32639162 DOI: 10.1021/acs.jpclett.0c01555] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The performance of photovoltaic devices made using semiconducting carbon nanotubes is limited by the transverse exciton diffusion length, which is ultimately set by intertube energy transfer. In this paper, we study whether extending the exciton lifetime improves energy transfer, by allowing more time for exciton transfer between carbon nanotubes, and thereby device performance. To do so, we prepare nanotubes by either shear-force mixing or ultrasonication, leading to different lengths and defect densities. We create thin films that mix (6,5) and (7,5) nanotubes and quantify the relative amounts of energy transfer in them using two-dimensional white-light (2DWL) spectroscopy and photoluminescence excitation (PLE) spectroscopy. Cross-peaks appearing in 2DWL spectra and quenching of the (6,5) PLE signal upon mixing both quantify energy transfer from (6,5) to (7,5). In both spectroscopies, energy transfer between shear-force mixed tubes is ∼20% more efficient. The cross-peaks in 2DWL spectra grow in at the same rate regardless of the processing method with the all shear-force mixed sample ultimately reaching a larger cross-peak amplitude. Shear-force mixing methods instead of sonication have improved external quantum efficiency in carbon nanotube devices by 30%. The spectroscopic results observed here link energy transfer to exciton diffusion and correlate to device performance.
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Affiliation(s)
- Jessica T Flach
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Jialiang Wang
- Department of Materials Science and Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Michael S Arnold
- Department of Materials Science and Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Martin T Zanni
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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9
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Wei X, Maimaitiyiming X. Selectable and Releasable Noncovalent Functionalization of Semiconducting SWCNTs by Biethynyl‐2,5‐bis(dodecoxy)benzene Unit‐Containing Conjugated Copolymers. MACROMOL CHEM PHYS 2020. [DOI: 10.1002/macp.202000086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Xia Wei
- Key Laboratory of Energy Materials ChemistryMinistry of Education; Key Laboratory of Advanced Functional MaterialsAutonomous Region; Institute of Applied ChemistrySchool of Chemistry and Chemical EngineeringXinjiang University Urumqi Xinjiang 830046 P. R. China
| | - Xieraili Maimaitiyiming
- Key Laboratory of Energy Materials ChemistryMinistry of Education; Key Laboratory of Advanced Functional MaterialsAutonomous Region; Institute of Applied ChemistrySchool of Chemistry and Chemical EngineeringXinjiang University Urumqi Xinjiang 830046 P. R. China
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10
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Li W, Vasenko AS, Tang J, Prezhdo OV. Anharmonicity Extends Carrier Lifetimes in Lead Halide Perovskites at Elevated Temperatures. J Phys Chem Lett 2019; 10:6219-6226. [PMID: 31556621 DOI: 10.1021/acs.jpclett.9b02553] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Lead halide perovskites constitute a very promising class of materials for a broad range of solar and optoelectronic applications. Perovskites exhibit many unusual properties, and recent experiments demonstrate an unusual temperature dependence of charge carrier lifetimes. Focusing on the all-inorganic CsPbBr3, and using a combination of ab initio nonadiabatic molecular dynamics and time-domain density functional theory, we demonstrate that the unconventional behavior arises because of a highly anharmonic nature of atomic motions in perovskites. As temperature increases, perovskite structure undergoes a notable deformation, reflected in tilting of octahedral units, and experiences large-scale anharmonic movements away from the equilibrium geometry. As a result, the electronic energy gap increases, and phonon-induced loss of coherence within the electronic subsystem accelerates. These two factors slow down nonradiative electron-hole recombination, which constitutes the main limitation on efficiencies of perovskite solar, optical, and electronic devices. The increase of charge carrier lifetimes with temperature is particularly beneficial in applications, because materials heat up, for instance, from sunlight during solar energy harvesting. The behavior of the all-inorganic halide perovskite investigated here is different from that of hybrid organic-inorganic perovskites, which exhibit additional disorder associated with reorientations of the asymmetric organic cations. The reported simulations generate an in-depth understanding of the unusual properties of inorganic perovskites, relevant for photocatalytic, photovoltaic, electronic, and optical applications.
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Affiliation(s)
- Wei Li
- College of Science , Hunan Agricultural University , Changsha 410128 , People's Republic of China
| | - Andrey S Vasenko
- National Research University Higher School of Economics , 101000 Moscow , Russia
| | - Jianfeng Tang
- College of Science , Hunan Agricultural University , Changsha 410128 , People's Republic of China
| | - Oleg V Prezhdo
- Department of Chemistry , University of Southern California , Los Angeles , California 90089 , United States
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11
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Liu D, Ni K, Ye J, Xie J, Zhu Y, Song L. Tailoring the Structure of Carbon Nanomaterials toward High-End Energy Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1802104. [PMID: 30129275 DOI: 10.1002/adma.201802104] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 07/03/2018] [Indexed: 05/26/2023]
Abstract
Carbon nanomaterials are perceived to be ideally suited candidates for high-end energy applications, owing to their unparalleled advantages including superior electric and thermal conductivity, excellent mechanical properties, and high specific surface areas. It has been demonstrated through several research contributions that the electrochemical performance of carbon nanomaterials significantly depends upon their versatile electronic structures and microstructures. These can be precisely tailored by rational defect engineering, heteroatom doping, heterostructure coupling, and pore fabrication, which largely affect the intrinsic nature of active sites and facilitate the ion/electron transfer. Herein, the recent progress in tailoring carbon nanostructures toward high-end electrocatalysis and supercapacitor applications is summarized, with an emphasis on synthesis strategies, advanced characterizations, and specific elucidation of structure-performance relationship. The challenges and opportunities for the rational design and detection of variously tailored carbon nanomaterials that can further improve the fundamental understanding and practical applications in the field of energy storage and conversion are also discussed.
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Affiliation(s)
- Daobin Liu
- National Synchrotron Radiation Laboratory, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui, 230029, P. R. China
| | - Kun Ni
- CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
| | - Jianglin Ye
- CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
| | - Jian Xie
- CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
| | - Yanwu Zhu
- CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
| | - Li Song
- National Synchrotron Radiation Laboratory, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui, 230029, P. R. China
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12
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Ishimoto K, Tajima T, Miyake H, Yamagami M, Kurashige W, Negishi Y, Takaguchi Y. Photo-induced H 2 evolution from water via the dissociation of excitons in water-dispersible single-walled carbon nanotube sensitizers. Chem Commun (Camb) 2018; 54:393-396. [PMID: 29250643 DOI: 10.1039/c7cc07194a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
To observe a clear-cut example of the formation of mobile carriers from excitons on semiconducting single-walled carbon nanotubes (s-SWCNTs) surrounded by a medium with a high dielectric constant, water-dispersible s-SWCNT nanocomposites were fabricated by physical modifications using poly(amidoamine) dendrimers that contain an aliphatic core. The evolution of H2 from water using these s-SWCNT/dendrimer nanocomposites as photosensitizers under irradiation with visible light demonstrated a photo-induced electron transfer from the s-SWCNTs to the co-catalysts.
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Affiliation(s)
- Kango Ishimoto
- Graduate School of Environmental and Life Science, Okayama University, 3-1-1 Tsushima-Naka, Kita-ku, Okayama 700-8530, Japan.
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13
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Große C, Merino P, Rosławska A, Gunnarsson O, Kuhnke K, Kern K. Submolecular Electroluminescence Mapping of Organic Semiconductors. ACS NANO 2017; 11:1230-1237. [PMID: 28085244 DOI: 10.1021/acsnano.6b08471] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The electroluminescence of organic films is the central aspect in organic light emitting diodes (OLEDs) and widely used in current display technology. However, its spatial variation on the molecular scale is essentially unexplored. Here, we address this issue by using scanning tunneling microscopy (STM) and present an in-depth study of the electroluminescence from thin C60 films (<10 monolayers) on Ag(111) and Au(111) surfaces. Similar to an OLED, the metal substrate and STM tip inject complementary charge carriers that may recombine within the molecular film; however, the atomically defined charge injection by the tip enables mapping of the local electroluminescence down to the submolecular scale. We show that the radiative recombination in solid C60 is restricted to various structural defects, whose emission characteristics can be addressed individually. The emission fine structure reveals a coupling to Jahn-Teller active vibrational modes of C60, which implies that its parity-forbidden lowest singlet transition becomes locally allowed at the emission centers. At lateral distances of a few nanometers, only a weak emission from tip-induced plasmons is detectable. Their excitation evidences the injection of both charge carrier types and confirms that they are unable to recombine radiatively at positions far from structural defects. Finally, we demonstrate that the molecular orbital pattern visible in electroluminescence maps enables an unambiguous discrimination between the intrinsic radiative recombination of electron-hole pairs in the organic film and the technique-related emission of tip-induced plasmons. This capability is essential to consolidate STM as a tool to explore the light generation from organic films on the nanoscale.
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Affiliation(s)
- Christoph Große
- Max-Planck-Institut für Festkörperforschung , Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Pablo Merino
- Max-Planck-Institut für Festkörperforschung , Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Anna Rosławska
- Max-Planck-Institut für Festkörperforschung , Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Olle Gunnarsson
- Max-Planck-Institut für Festkörperforschung , Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Klaus Kuhnke
- Max-Planck-Institut für Festkörperforschung , Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Klaus Kern
- Max-Planck-Institut für Festkörperforschung , Heisenbergstraße 1, 70569 Stuttgart, Germany
- Institut de Physique, École Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland
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14
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Hartmann NF, Pramanik R, Dowgiallo AM, Ihly R, Blackburn JL, Doorn SK. Photoluminescence Imaging of Polyfluorene Surface Structures on Semiconducting Carbon Nanotubes: Implications for Thin Film Exciton Transport. ACS NANO 2016; 10:11449-11458. [PMID: 27936574 DOI: 10.1021/acsnano.6b07168] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Single-walled carbon nanotubes (SWCNTs) have potential to act as light-harvesting elements in thin film photovoltaic devices, but performance is in part limited by the efficiency of exciton diffusion processes within the films. Factors contributing to exciton transport can include film morphology encompassing nanotube orientation, connectivity, and interaction geometry. Such factors are often defined by nanotube surface structures that are not yet well understood. Here, we present the results of a combined pump-probe and photoluminescence imaging study of polyfluorene (PFO)-wrapped (6,5) and (7,5) SWCNTs that provide additional insight into the role played by polymer structures in defining exciton transport. Pump-probe measurements suggest exciton transport occurs over larger length scales in films composed of PFO-wrapped (7,5) SWCNTs, compared to those prepared from PFO-bpy-wrapped (6,5) SWCNTs. To explore the role the difference in polymer structure may play as a possible origin of differing transport behaviors, we performed a photoluminescence imaging study of individual polymer-wrapped (6,5) and (7,5) SWCNTs. The PFO-bpy-wrapped (6,5) SWCNTs showed more uniform intensity distributions along their lengths, in contrast to the PFO-wrapped (7,5) SWCNTs, which showed irregular, discontinuous intensity distributions. These differences likely originate from differences in surface coverage and suggest the PFO wrapping on (7,5) nanotubes produces a more open surface structure than is available with the PFO-bpy wrapping of (6,5) nanotubes. The open structure likely leads to improved intertube coupling that enhances exciton transport within the (7,5) films, consistent with the results of our pump-probe measurements.
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Affiliation(s)
- Nicolai F Hartmann
- Center for Integrated Nanotechnologies, MPA-CINT, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
| | - Rajib Pramanik
- Center for Integrated Nanotechnologies, MPA-CINT, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
| | | | - Rachelle Ihly
- National Renewable Energy Laboratory , Golden, Colorado 80401, United States
| | - Jeffrey L Blackburn
- National Renewable Energy Laboratory , Golden, Colorado 80401, United States
| | - Stephen K Doorn
- Center for Integrated Nanotechnologies, MPA-CINT, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
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Serbenta A, Kozlov OV, Portale G, van Loosdrecht PHM, Pshenichnikov MS. Bulk heterojunction morphology of polymer:fullerene blends revealed by ultrafast spectroscopy. Sci Rep 2016; 6:36236. [PMID: 27824085 PMCID: PMC5099942 DOI: 10.1038/srep36236] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 10/13/2016] [Indexed: 01/23/2023] Open
Abstract
Morphology of organic photovoltaic bulk heterojunctions (BHJs) - a nanoscale texture of the donor and acceptor phases - is one of the key factors influencing efficiency of organic solar cells. Detailed knowledge of the morphology is hampered by the fact that it is notoriously difficult to investigate by microscopic methods. Here we all-optically track the exciton harvesting dynamics in the fullerene acceptor phase from which subdivision of the fullerene domain sizes into the mixed phase (2-15 nm) and large (>50 nm) domains is readily obtained via the Monte-Carlo simulations. These results were independently confirmed by a combination of X-ray scattering, electron and atomic-force microscopies, and time-resolved photoluminescence spectroscopy. In the large domains, the excitons are lost due to the high energy disorder while in the ordered materials the excitons are harvested with high efficiency even from the domains as large as 100 nm due to the absence of low-energy traps. Therefore, optimizing of blend nanomorphology together with increasing the material order are deemed as winning strategies in the exciton harvesting optimization.
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Affiliation(s)
- Almis Serbenta
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands
| | - Oleg V. Kozlov
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands
- International Laser Center and Faculty of Physics, Moscow State University, Russian Federation
| | - Giuseppe Portale
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands
| | | | - Maxim S. Pshenichnikov
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands
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16
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Brady GJ, Way AJ, Safron NS, Evensen HT, Gopalan P, Arnold MS. Quasi-ballistic carbon nanotube array transistors with current density exceeding Si and GaAs. SCIENCE ADVANCES 2016; 2:e1601240. [PMID: 27617293 PMCID: PMC5010372 DOI: 10.1126/sciadv.1601240] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/05/2016] [Indexed: 05/21/2023]
Abstract
Carbon nanotubes (CNTs) are tantalizing candidates for semiconductor electronics because of their exceptional charge transport properties and one-dimensional electrostatics. Ballistic transport approaching the quantum conductance limit of 2G 0 = 4e (2)/h has been achieved in field-effect transistors (FETs) containing one CNT. However, constraints in CNT sorting, processing, alignment, and contacts give rise to nonidealities when CNTs are implemented in densely packed parallel arrays such as those needed for technology, resulting in a conductance per CNT far from 2G 0. The consequence has been that, whereas CNTs are ultimately expected to yield FETs that are more conductive than conventional semiconductors, CNTs, instead, have underperformed channel materials, such as Si, by sixfold or more. We report quasi-ballistic CNT array FETs at a density of 47 CNTs μm(-1), fabricated through a combination of CNT purification, solution-based assembly, and CNT treatment. The conductance is as high as 0.46 G 0 per CNT. In parallel, the conductance of the arrays reaches 1.7 mS μm(-1), which is seven times higher than the previous state-of-the-art CNT array FETs made by other methods. The saturated on-state current density is as high as 900 μA μm(-1) and is similar to or exceeds that of Si FETs when compared at and equivalent gate oxide thickness and at the same off-state current density. The on-state current density exceeds that of GaAs FETs as well. This breakthrough in CNT array performance is a critical advance toward the exploitation of CNTs in logic, high-speed communications, and other semiconductor electronics technologies.
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Affiliation(s)
- Gerald J. Brady
- Department of Materials Science and Engineering, University of Wisconsin-Madison, 1509 University Avenue, Madison, WI 53706, USA
| | - Austin J. Way
- Department of Materials Science and Engineering, University of Wisconsin-Madison, 1509 University Avenue, Madison, WI 53706, USA
| | - Nathaniel S. Safron
- Department of Materials Science and Engineering, University of Wisconsin-Madison, 1509 University Avenue, Madison, WI 53706, USA
| | - Harold T. Evensen
- Department of Engineering Physics, University of Wisconsin-Platteville, 1 University Plaza, Platteville, WI 53818, USA
| | - Padma Gopalan
- Department of Materials Science and Engineering, University of Wisconsin-Madison, 1509 University Avenue, Madison, WI 53706, USA
| | - Michael S. Arnold
- Department of Materials Science and Engineering, University of Wisconsin-Madison, 1509 University Avenue, Madison, WI 53706, USA
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