1
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Amin M, Koessler ER, Morshed O, Awan F, Cogan NMB, Collison R, Tumiel TM, Girten W, Leiter C, Vamivakas AN, Huo P, Krauss TD. Cavity Controlled Upconversion in CdSe Nanoplatelet Polaritons. ACS NANO 2024; 18:21388-21398. [PMID: 39078943 PMCID: PMC11328175 DOI: 10.1021/acsnano.4c05871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/18/2024]
Abstract
Exciton-polaritons provide a versatile platform for investigating quantum electrodynamics effects in chemical systems, such as polariton-altered chemical reactivity. However, using polaritons in chemical contexts will require a better understanding of their photophysical properties under ambient conditions, where chemistry is typically performed. Here, we used cavity quality factor to control strong light-matter interactions and in particular the excited state dynamics of colloidal CdSe nanoplatelets (NPLs) coupled to a Fabry-Pérot optical cavity. With increasing cavity quality factor, we observe significant population of the upper polariton (UP) state, exemplified by the rare observation of substantial UP photoluminescence (PL). Excitation of the lower polariton (LP) states results in upconverted PL emission from the UP branch due to efficient exchange of population between the LP, UP and the reservoir of dark states present in collectively coupled polaritonic systems. In addition, we measure time scales for polariton dynamics ∼100 ps, implying great potential for NPL based polariton systems to affect photochemical reaction rates. State-of-the-art quantum dynamical simulations show outstanding quantitative agreement with experiments, and thus provide important insight into polariton photophysical dynamics of collectively coupled nanocrystal-based systems. These findings represent a significant step toward the development of practical polariton photochemistry platforms.
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Affiliation(s)
- Mitesh Amin
- The Institute of Optics, University of Rochester, Rochester, New York 14627, United States
| | - Eric R Koessler
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Ovishek Morshed
- The Institute of Optics, University of Rochester, Rochester, New York 14627, United States
| | - Farwa Awan
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Nicole M B Cogan
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Robert Collison
- The Institute of Optics, University of Rochester, Rochester, New York 14627, United States
| | - Trevor M Tumiel
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - William Girten
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Christopher Leiter
- Department of Chemistry, Regis University, Denver, Colorado 80221, United States
| | - A Nickolas Vamivakas
- The Institute of Optics, University of Rochester, Rochester, New York 14627, United States
- Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, United States
| | - Pengfei Huo
- The Institute of Optics, University of Rochester, Rochester, New York 14627, United States
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Todd D Krauss
- The Institute of Optics, University of Rochester, Rochester, New York 14627, United States
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
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2
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Wieland S, El Yumin AA, Settele S, Zaumseil J. Photo-Activated, Solid-State Introduction of Luminescent Oxygen Defects into Semiconducting Single-Walled Carbon Nanotubes. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2024; 128:2012-2021. [PMID: 38352856 PMCID: PMC10860128 DOI: 10.1021/acs.jpcc.3c07000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 12/17/2023] [Accepted: 01/11/2024] [Indexed: 02/16/2024]
Abstract
Oxygen defects in semiconducting single-walled carbon nanotubes (SWCNTs) are localized disruptions in the carbon lattice caused by the formation of epoxy or ether groups, commonly through wet-chemical reactions. The associated modifications of the electronic structure can result in luminescent states with emission energies below those of pristine SWCNTs in the near-infrared range, which makes them promising candidates for applications in biosensing and as single-photon emitters. Here, we demonstrate the controlled introduction of luminescent oxygen defects into networks of monochiral (6,5) SWCNTs using a solid-state photocatalytic approach. UV irradiation of SWCNTs on the photoreactive surfaces of the transition metal oxides TiOx and ZnOx in the presence of trace amounts of water and oxygen results in the creation of reactive oxygen species that initiate radical reactions with the carbon lattice and the formation of oxygen defects. The created ether-d and epoxide-l defect configurations give rise to two distinct red-shifted emissive features. The chemical and dielectric properties of the photoactive oxides influence the final defect emission properties, with oxygen-functionalized SWCNTs on TiOx substrates being brighter than those on ZnOx or pristine SWCNTs on glass. The photoinduced functionalization of nanotubes is further employed to create lateral patterns of oxygen defects in (6,5) SWCNT networks with micrometer resolution and thus spatially controlled defect emission.
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Affiliation(s)
- Sonja Wieland
- Institute for Physical Chemistry, Universität Heidelberg, D-69120 Heidelberg, Germany
| | | | - Simon Settele
- Institute for Physical Chemistry, Universität Heidelberg, D-69120 Heidelberg, Germany
| | - Jana Zaumseil
- Institute for Physical Chemistry, Universität Heidelberg, D-69120 Heidelberg, Germany
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3
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Sokolovskii I, Tichauer RH, Morozov D, Feist J, Groenhof G. Multi-scale molecular dynamics simulations of enhanced energy transfer in organic molecules under strong coupling. Nat Commun 2023; 14:6613. [PMID: 37857599 PMCID: PMC10587084 DOI: 10.1038/s41467-023-42067-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 09/21/2023] [Indexed: 10/21/2023] Open
Abstract
Exciton transport can be enhanced in the strong coupling regime where excitons hybridize with confined light modes to form polaritons. Because polaritons have group velocity, their propagation should be ballistic and long-ranged. However, experiments indicate that organic polaritons propagate in a diffusive manner and more slowly than their group velocity. Here, we resolve this controversy by means of molecular dynamics simulations of Rhodamine molecules in a Fabry-Pérot cavity. Our results suggest that polariton propagation is limited by the cavity lifetime and appears diffusive due to reversible population transfers between polaritonic states that propagate ballistically at their group velocity, and dark states that are stationary. Furthermore, because long-lived dark states transiently trap the excitation, propagation is observed on timescales beyond the intrinsic polariton lifetime. These insights not only help to better understand and interpret experimental observations, but also pave the way towards rational design of molecule-cavity systems for coherent exciton transport.
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Affiliation(s)
- Ilia Sokolovskii
- Nanoscience Center and Department of Chemistry, University of Jyväskylä, P.O. Box 35, Jyväskylä, 40014, Finland
| | - Ruth H Tichauer
- Nanoscience Center and Department of Chemistry, University of Jyväskylä, P.O. Box 35, Jyväskylä, 40014, Finland
- Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid, Spain
| | - Dmitry Morozov
- Nanoscience Center and Department of Chemistry, University of Jyväskylä, P.O. Box 35, Jyväskylä, 40014, Finland
| | - Johannes Feist
- Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid, Spain
| | - Gerrit Groenhof
- Nanoscience Center and Department of Chemistry, University of Jyväskylä, P.O. Box 35, Jyväskylä, 40014, Finland.
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4
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Bhuyan R, Mony J, Kotov O, Castellanos GW, Gómez Rivas J, Shegai TO, Börjesson K. The Rise and Current Status of Polaritonic Photochemistry and Photophysics. Chem Rev 2023; 123:10877-10919. [PMID: 37683254 PMCID: PMC10540218 DOI: 10.1021/acs.chemrev.2c00895] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Indexed: 09/10/2023]
Abstract
The interaction between molecular electronic transitions and electromagnetic fields can be enlarged to the point where distinct hybrid light-matter states, polaritons, emerge. The photonic contribution to these states results in increased complexity as well as an opening to modify the photophysics and photochemistry beyond what normally can be seen in organic molecules. It is today evident that polaritons offer opportunities for molecular photochemistry and photophysics, which has caused an ever-rising interest in the field. Focusing on the experimental landmarks, this review takes its reader from the advent of the field of polaritonic chemistry, over the split into polariton chemistry and photochemistry, to present day status within polaritonic photochemistry and photophysics. To introduce the field, the review starts with a general description of light-matter interactions, how to enhance these, and what characterizes the coupling strength. Then the photochemistry and photophysics of strongly coupled systems using Fabry-Perot and plasmonic cavities are described. This is followed by a description of room-temperature Bose-Einstein condensation/polariton lasing in polaritonic systems. The review ends with a discussion on the benefits, limitations, and future developments of strong exciton-photon coupling using organic molecules.
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Affiliation(s)
- Rahul Bhuyan
- Department
of Chemistry and Molecular Biology, University
of Gothenburg, 412 96 Göteborg, Sweden
| | - Jürgen Mony
- Department
of Chemistry and Molecular Biology, University
of Gothenburg, 412 96 Göteborg, Sweden
| | - Oleg Kotov
- Department
of Physics, Chalmers University of Technology, 412 96 Göteborg, Sweden
| | - Gabriel W. Castellanos
- Department
of Applied Physics and Science Education, Eindhoven Hendrik Casimir
Institute and Institute for Complex Molecular Systems, Eindhoven University of Technology, 5612 AE Eindhoven, The Netherlands
| | - Jaime Gómez Rivas
- Department
of Applied Physics and Science Education, Eindhoven Hendrik Casimir
Institute and Institute for Complex Molecular Systems, Eindhoven University of Technology, 5612 AE Eindhoven, The Netherlands
| | - Timur O. Shegai
- Department
of Physics, Chalmers University of Technology, 412 96 Göteborg, Sweden
| | - Karl Börjesson
- Department
of Chemistry and Molecular Biology, University
of Gothenburg, 412 96 Göteborg, Sweden
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5
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Weight BM, Sifain AE, Gifford BJ, Htoon H, Tretiak S. On-the-Fly Nonadiabatic Dynamics Simulations of Single-Walled Carbon Nanotubes with Covalent Defects. ACS NANO 2023; 17:6208-6219. [PMID: 36972076 DOI: 10.1021/acsnano.2c08579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Single-walled carbon nanotubes (SWCNTs) with covalent surface defects have been explored recently due to their promise for use in single-photon telecommunication emission and in spintronic applications. The all-atom dynamic evolution of electrostatically bound excitons (the primary electronic excitations) in these systems has only been loosely explored from a theoretical perspective due to the size limitations of these large systems (>500 atoms). In this work, we present computational modeling of nonradiative relaxation in a variety of SWCNT chiralities with single-defect functionalizations. Our excited-state dynamics modeling uses a trajectory surface hopping algorithm accounting for excitonic effects with a configuration interaction approach. We find a strong chirality and defect-composition dependence on the population relaxation (varying over 50-500 fs) between the primary nanotube band gap excitation E11 and the defect-associated, single-photon-emitting E11* state. These simulations give direct insight into the relaxation between the band-edge states and the localized excitonic state, in competition with dynamic trapping/detrapping processes observed in experiment. Engineering fast population decay into the quasi-two-level subsystem with weak coupling to higher-energy states increases the effectiveness and controllability of these quantum light emitters.
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Affiliation(s)
- Braden M Weight
- Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, United States
- Center for Integrated Nanotechnologies, Center for Nonlinear Studies, and Theoretical Division Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Andrew E Sifain
- Department of Chemistry, Princeton University, Princeton, New Jersey 08540 United States
| | - Brendan J Gifford
- Center for Integrated Nanotechnologies, Center for Nonlinear Studies, and Theoretical Division Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Han Htoon
- Center for Integrated Nanotechnologies, Center for Nonlinear Studies, and Theoretical Division Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Sergei Tretiak
- Center for Integrated Nanotechnologies, Center for Nonlinear Studies, and Theoretical Division Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
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6
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Li Y, Jiang JW. Modulation of thermal conductivity of single-walled carbon nanotubes by fullerene encapsulation: the effect of vacancy defects. Phys Chem Chem Phys 2023; 25:7734-7740. [PMID: 36880294 DOI: 10.1039/d2cp04638e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Single-walled carbon nanotubes (SWCNTs) possess extremely high thermal conductivity that benefits their application in high-performance electronic devices. The characteristic hollow configuration of SWCNTs is not favorable for the buckling stability of the structure, which is typically resolved by fullerene encapsulation in practice. To investigate the fullerene encapsulation effect on thermal conductivity, we perform molecular dynamics simulations to comparatively study the thermal conductivity of pure SWCNTs and fullerene encapsulated SWCNTs. We focus on disclosing the relationship between the vacancy defect and the fullerene encapsulation effect on thermal conductivity. It is quite interesting that vacancy defects weaken the coupling strength between the nanotube shell and the fullerene, especially for narrower SWCNTs (9, 9), which will considerably reduce the effect of fullerene encapsulation on the thermal conductivity of narrower SWCNTs. However, for thicker SWCNTs (10, 10) and (11, 11), vacancy defects have an ignorable effect on the coupling strength between the nanotube shell and the fullerene due to plenty of free space in thicker SWCNTs, so vacancy defects are not important for the fullerene encapsulation effect on the thermal conductivity of thicker SWCNTs. These findings shall be valuable for the application of SWCNTs in thermoelectric fields.
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Affiliation(s)
- Yu Li
- Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai Institute of Aircraft Mechanics and Control, Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Frontier Science Center of Mechanoinformatics, School of Mechanics and Engineering Science, Shanghai University, Shanghai 200072, People's Republic of China.
| | - Jin-Wu Jiang
- Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai Institute of Aircraft Mechanics and Control, Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Frontier Science Center of Mechanoinformatics, School of Mechanics and Engineering Science, Shanghai University, Shanghai 200072, People's Republic of China. .,Zhejiang Laboratory, Hangzhou 311100, China
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7
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Weight B, Zheng M, Tretiak S. Signatures of Chemical Dopants in Simulated Resonance Raman Spectroscopy of Carbon Nanotubes. J Phys Chem Lett 2023; 14:1182-1191. [PMID: 36715511 PMCID: PMC9923748 DOI: 10.1021/acs.jpclett.2c03591] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 01/26/2023] [Indexed: 06/18/2023]
Abstract
Single-walled carbon nanotubes (SWCNTs) with organic sp2 or sp3 hybridization defects allow the robust tunability of many optoelectronic properties in these topologically interesting quasi-one-dimensional materials. Recent resonant Raman experiments have illuminated new features in the intermediate-frequency region upon functionalization that change with the degree of functionalization as well as with interactions between defect sites. In this Letter, we report ab initio simulated near-resonant Raman spectroscopy results for pristine and chemically functionalized SWCNT models and find new features concomitant with experimental observations. We are able to assign the character of these features by varying the frequency of the external Raman laser frequency near the defect-induced E11* optical transition using a perturbative treatment of the electronic structure of the system. The obtained insights establish relationships between the nanotube atomistic structure and Raman spectra facilitating further exploration of SWCNTs with tunable optical properties tuned by chemical functionalization.
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Affiliation(s)
- Braden
M. Weight
- Department
of Physics and Astronomy, University of
Rochester, Rochester, New York 14627, United States
- Center
for Integrated Nanotechnologies, Center for Nonlinear Studies, and
Theoretical Division, Los Alamos National
Laboratory, Los Alamos, New Mexico 87545, United States
| | - Ming Zheng
- Materials
Science and Engineering Division, National
Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Sergei Tretiak
- Center
for Integrated Nanotechnologies, Center for Nonlinear Studies, and
Theoretical Division, Los Alamos National
Laboratory, Los Alamos, New Mexico 87545, United States
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8
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Tichauer RH, Morozov D, Sokolovskii I, Toppari JJ, Groenhof G. Identifying Vibrations that Control Non-adiabatic Relaxation of Polaritons in Strongly Coupled Molecule-Cavity Systems. J Phys Chem Lett 2022; 13:6259-6267. [PMID: 35771724 PMCID: PMC9289944 DOI: 10.1021/acs.jpclett.2c00826] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The strong light-matter coupling regime, in which excitations of materials hybridize with excitations of confined light modes into polaritons, holds great promise in various areas of science and technology. A key aspect for all applications of polaritonic chemistry is the relaxation into the lower polaritonic states. Polariton relaxation is speculated to involve two separate processes: vibrationally assisted scattering (VAS) and radiative pumping (RP), but the driving forces underlying these two mechanisms are not fully understood. To provide mechanistic insights, we performed multiscale molecular dynamics simulations of tetracene molecules strongly coupled to the confined light modes of an optical cavity. The results suggest that both mechanisms are driven by the same molecular vibrations that induce relaxation through nonadiabatic coupling between dark states and polaritonic states. Identifying these vibrational modes provides a rationale for enhanced relaxation into the lower polariton when the cavity detuning is resonant with specific vibrational transitions.
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Affiliation(s)
- Ruth H. Tichauer
- Nanoscience
Center and Department of Chemistry, University
of Jyväskylä, P.O. Box 35, 40014 Jyväskylä, Finland
| | - Dmitry Morozov
- Nanoscience
Center and Department of Chemistry, University
of Jyväskylä, P.O. Box 35, 40014 Jyväskylä, Finland
| | - Ilia Sokolovskii
- Nanoscience
Center and Department of Chemistry, University
of Jyväskylä, P.O. Box 35, 40014 Jyväskylä, Finland
| | - J. Jussi Toppari
- Nanoscience
Center and Department of Physics, University
of Jyväskylä, P.O. Box 35, 40014 Jyväskylä, Finland
| | - Gerrit Groenhof
- Nanoscience
Center and Department of Chemistry, University
of Jyväskylä, P.O. Box 35, 40014 Jyväskylä, Finland
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9
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Lüttgens JM, Kuang Z, Zorn NF, Buckup T, Zaumseil J. Evidence for a Polariton-Mediated Biexciton Transition in Single-Walled Carbon Nanotubes. ACS PHOTONICS 2022; 9:1567-1576. [PMID: 35607642 PMCID: PMC9121424 DOI: 10.1021/acsphotonics.1c01590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Indexed: 06/15/2023]
Abstract
Strong coupling of excitonic resonances with a cavity gives rise to exciton-polaritons which possess a modified energy landscape compared to the uncoupled emitter. However, due to the femtosecond lifetime of the so-called bright polariton states and transient changes of the cavity reflectivity under excitation, it is challenging to directly measure the polariton excited state dynamics. Here, near-infrared pump-probe spectroscopy is used to investigate the ultrafast dynamics of exciton-polaritons based on strongly coupled (6,5) single-walled carbon nanotubes in metal-clad microcavities. We present a protocol for fitting the reflectivity-associated response of the cavity using genetic algorithm-assisted transfer-matrix simulations. With this approach, we are able to identify an absorptive exciton-polariton feature in the transient transmission data. This feature appears instantaneously under resonant excitation of the upper polariton but is delayed for off-resonant excitation. The observed transition energy and detuning dependence point toward a direct upper polariton-to-biexciton transition. Our results provide direct evidence for exciton-polariton intrinsic transitions beyond the bright polariton lifetime in strongly coupled microcavities.
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Affiliation(s)
- Jan M. Lüttgens
- Institute
for Physical Chemistry, Universität
Heidelberg, D-69120 Heidelberg, Germany
| | - Zhuoran Kuang
- Institute
for Physical Chemistry, Universität
Heidelberg, D-69120 Heidelberg, Germany
- Centre
for Advanced Materials, Universität
Heidelberg, D-69120 Heidelberg, Germany
| | - Nicolas F. Zorn
- Institute
for Physical Chemistry, Universität
Heidelberg, D-69120 Heidelberg, Germany
| | - Tiago Buckup
- Institute
for Physical Chemistry, Universität
Heidelberg, D-69120 Heidelberg, Germany
- Centre
for Advanced Materials, Universität
Heidelberg, D-69120 Heidelberg, Germany
| | - Jana Zaumseil
- Institute
for Physical Chemistry, Universität
Heidelberg, D-69120 Heidelberg, Germany
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10
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Vasista AB, Menghrajani KS, Barnes WL. Polariton assisted photoemission from a layered molecular material: role of vibrational states and molecular absorption. NANOSCALE 2021; 13:14497-14505. [PMID: 34473173 PMCID: PMC8412029 DOI: 10.1039/d1nr03913j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 08/07/2021] [Indexed: 06/13/2023]
Abstract
The way molecules absorb, transfer, and emit light can be modified by coupling them to optical cavities. The extent of the modification is often defined by the cavity-molecule coupling strength, which depends on the number of coupled molecules. We experimentally and numerically study the evolution of photoemission from a thin layered J-aggregated molecular material strongly coupled to a Fabry-Perot microcavity as a function of the number of coupled layers. We unveil an important difference between the strong coupling signatures obtained from reflection spectroscopy and from polariton assisted photoluminescence. We also study the effect of the vibrational modes supported by the molecular material on the polariton assisted emission both for a focused laser beam and for normally incident excitation, for two different excitation wavelengths: a laser in resonance with the lower polariton branch, and a laser not in resonance. We found that Raman scattered photons appear to play an important role in populating the lower polariton branch, especially when the system was excited with a laser in resonance with the lower polariton branch. We also found that the polariton assisted photoemission depends on the extent of modification of the molecular absorption induced by the molecule-cavity coupling.
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11
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Zorn N, Berger FJ, Zaumseil J. Charge Transport in and Electroluminescence from sp 3-Functionalized Carbon Nanotube Networks. ACS NANO 2021; 15:10451-10463. [PMID: 34048654 PMCID: PMC8223481 DOI: 10.1021/acsnano.1c02878] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The controlled covalent functionalization of semiconducting single-walled carbon nanotubes (SWCNTs) with luminescent sp3 defects leads to additional narrow and tunable photoluminescence features in the near-infrared and even enables single-photon emission at room temperature, thus strongly expanding their application potential. However, the successful integration of sp3-functionalized SWCNTs in optoelectronic devices with efficient defect state electroluminescence not only requires control over their emission properties but also a detailed understanding of the impact of functionalization on their electrical performance, especially in dense networks. Here, we demonstrate ambipolar, light-emitting field-effect transistors based on networks of pristine and functionalized polymer-sorted (6,5) SWCNTs. We investigate the influence of sp3 defects on charge transport by employing electroluminescence and (charge-modulated) photoluminescence spectroscopy combined with temperature-dependent current-voltage measurements. We find that sp3-functionalized SWCNTs actively participate in charge transport within the network as mobile carriers efficiently sample the sp3 defects, which act as shallow trap states. While both hole and electron mobilities decrease with increasing degree of functionalization, the transistors remain fully operational, showing electroluminescence from the defect states that can be tuned by the defect density.
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12
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Hulkko E, Pikker S, Tiainen V, Tichauer RH, Groenhof G, Toppari JJ. Effect of molecular Stokes shift on polariton dynamics. J Chem Phys 2021; 154:154303. [PMID: 33887943 DOI: 10.1063/5.0037896] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
When the enhanced electromagnetic field of a confined light mode interacts with photoactive molecules, the system can be driven into the regime of strong coupling, where new hybrid light-matter states, polaritons, are formed. Polaritons, manifested by the Rabi split in the dispersion, have shown potential for controlling the chemistry of the coupled molecules. Here, we show by angle-resolved steady-state experiments accompanied by multi-scale molecular dynamics simulations that the molecular Stokes shift plays a significant role in the relaxation of polaritons formed by organic molecules embedded in a polymer matrix within metallic Fabry-Pérot cavities. Our results suggest that in the case of Rhodamine 6G, a dye with a significant Stokes shift, excitation of the upper polariton leads to a rapid localization of the energy into the fluorescing state of one of the molecules, from where the energy scatters into the lower polariton (radiative pumping), which then emits. In contrast, for excitonic J-aggregates with a negligible Stokes shift, the fluorescing state does not provide an efficient relaxation gateway. Instead, the relaxation is mediated by exchanging energy quanta matching the energy gap between the dark states and lower polariton into vibrational modes (vibrationally assisted scattering). To understand better how the fluorescing state of a molecule that is not strongly coupled to the cavity can transfer its excitation energy to the lower polariton in the radiative pumping mechanism, we performed multi-scale molecular dynamics simulations. The results of these simulations suggest that non-adiabatic couplings between uncoupled molecules and the polaritons are the driving force for this energy transfer process.
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Affiliation(s)
- E Hulkko
- Department of Physics and Nanoscience Center, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland
| | - S Pikker
- Department of Physics and Nanoscience Center, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland
| | - V Tiainen
- Department of Physics and Nanoscience Center, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland
| | - R H Tichauer
- Department of Chemistry and Nanoscience Center, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland
| | - G Groenhof
- Department of Chemistry and Nanoscience Center, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland
| | - J J Toppari
- Department of Physics and Nanoscience Center, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland
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