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Nelson JC, Weichman ML. More than just smoke and mirrors: Gas-phase polaritons for optical control of chemistry. J Chem Phys 2024; 161:074304. [PMID: 39145566 DOI: 10.1063/5.0220077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2024] [Accepted: 07/08/2024] [Indexed: 08/16/2024] Open
Abstract
Gas-phase molecules are a promising platform to elucidate the mechanisms of action and scope of polaritons for optical control of chemistry. Polaritons arise from the strong coupling of a dipole-allowed molecular transition with the photonic mode of an optical cavity. There is mounting evidence of modified reactivity under polaritonic conditions; however, the complex condensed-phase environment of most experimental demonstrations impedes mechanistic understanding of this phenomenon. While the gas phase was the playground of early efforts in atomic cavity quantum electrodynamics, we have only recently demonstrated the formation of molecular polaritons under these conditions. Studying the reactivity of isolated gas-phase molecules under strong coupling would eliminate solvent interactions and enable quantum state resolution of reaction progress. In this Perspective, we contextualize recent gas-phase efforts in the field of polariton chemistry and offer a practical guide for experimental design moving forward.
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Affiliation(s)
- Jane C Nelson
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Marissa L Weichman
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
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2
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Dutta A, Tiainen V, Sokolovskii I, Duarte L, Markešević N, Morozov D, Qureshi HA, Pikker S, Groenhof G, Toppari JJ. Thermal disorder prevents the suppression of ultra-fast photochemistry in the strong light-matter coupling regime. Nat Commun 2024; 15:6600. [PMID: 39097575 PMCID: PMC11297929 DOI: 10.1038/s41467-024-50532-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 07/11/2024] [Indexed: 08/05/2024] Open
Abstract
Strong coupling between molecules and confined light modes of optical cavities to form polaritons can alter photochemistry, but the origin of this effect remains largely unknown. While theoretical models suggest a suppression of photochemistry due to the formation of new polaritonic potential energy surfaces, many of these models do not account for the energetic disorder among the molecules, which is unavoidable at ambient conditions. Here, we combine simulations and experiments to show that for an ultra-fast photochemical reaction such thermal disorder prevents the modification of the potential energy surface and that suppression is due to radiative decay of the lossy cavity modes. We also show that the excitation spectrum under strong coupling is a product of the excitation spectrum of the bare molecules and the absorption spectrum of the molecule-cavity system, suggesting that polaritons can act as gateways for channeling an excitation into a molecule, which then reacts normally. Our results therefore imply that strong coupling provides a means to tune the action spectrum of a molecule, rather than to change the reaction.
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Affiliation(s)
- Arpan Dutta
- Nanoscience Center and Department of Physics, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland
- Department of Mechanical and Materials Engineering, University of Turku, 20014, Turku, Finland
| | - Ville Tiainen
- Nanoscience Center and Department of Physics, 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
| | - Luís Duarte
- Nanoscience Center and Department of Physics, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland
- Department of Chemistry, University of Helsinki, P.O. Box 55, 00014, Helsinki, Finland
| | - Nemanja Markešević
- Nanoscience Center and Department of Physics, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland
- CNR-INO Istituto Nazionale di Ottica del Consiglio Nazionale delle Ricerche and LENS European Laboratory for Nonlinear Spectroscopy, Via Nello Carrara 1, Sesto Fiorentino, 50019, Italy
| | - Dmitry Morozov
- Nanoscience Center and Department of Chemistry, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland
| | - Hassan A Qureshi
- Nanoscience Center and Department of Physics, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland
- Department of Mechanical and Materials Engineering, University of Turku, 20014, Turku, Finland
| | - Siim Pikker
- Nanoscience Center and Department of Physics, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland
- Institute of Physics, University of Tartu, W. Ostwaldi 1, 50411, Tartu, Estonia
| | - Gerrit Groenhof
- 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.
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3
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Thomas PA, Barnes WL. Strong coupling-induced frequency shifts of highly detuned photonic modes in multimode cavities. J Chem Phys 2024; 160:204303. [PMID: 38804495 DOI: 10.1063/5.0208379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Accepted: 05/07/2024] [Indexed: 05/29/2024] Open
Abstract
Strong coupling between light and molecules is a fascinating topic exploring the implications of the hybridization of photonic and molecular states. For example, many recent experiments have explored the possibility that strong coupling of photonic and vibrational modes might modify chemical reaction rates. In these experiments, reactants are introduced into a planar cavity, and the vibrational mode of a chemical bond strongly couples to one of the many photonic modes supported by the cavity. Some experiments quantify reaction rates by tracking the spectral shift of higher-order cavity modes that are highly detuned from the vibrational mode of the reactant. Here, we show that the spectral position of these cavity modes, even though they are highly detuned, can still be influenced by strong coupling. We highlight the need to consider this strong coupling-induced frequency shift of cavity modes if one is to avoid underestimating cavity-induced reaction rate changes. We anticipate that our work will assist in the re-analysis of several high-profile results and has implications for the design of future strong coupling experiments.
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Affiliation(s)
- Philip A Thomas
- Department of Physics and Astronomy, University of Exeter, Exeter EX4 4QL, United Kingdom
| | - William L Barnes
- Department of Physics and Astronomy, University of Exeter, Exeter EX4 4QL, United Kingdom
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4
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Lee I, Melton SR, Xu D, Delor M. Controlling Molecular Photoisomerization in Photonic Cavities through Polariton Funneling. J Am Chem Soc 2024; 146:9544-9553. [PMID: 38530932 DOI: 10.1021/jacs.3c11292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
Strong coupling between photonic modes and molecular electronic excitations, creating hybrid light-matter states called polaritons, is an attractive avenue for controlling chemical reactions. Nevertheless, experimental demonstrations of polariton-modified chemical reactions remain sparse. Here, we demonstrate modified photoisomerization kinetics of merocyanine and diarylethene by coupling the reactant's optical transition with photonic microcavity modes. We leverage broadband Fourier-plane optical microscopy to noninvasively and rapidly monitor photoisomerization within microcavities, enabling systematic investigation of chemical kinetics for different cavity-exciton detunings and photoexcitation conditions. We demonstrate three distinct effects of cavity coupling: first, a renormalization of the photonic density of states, akin to a Purcell effect, leads to enhanced absorption and isomerization rates at certain wavelengths, notably red-shifting the onset of photoisomerization. This effect is present under both strong and weak light-matter couplings. Second, kinetic competition between polariton localization into reactive molecular states and cavity losses leads to a suppression of the photoisomerization yield. Finally, our key result is that in reaction mixtures with multiple reactant isomers, exhibiting partially overlapping optical transitions and distinct isomerization pathways, the cavity resonance can be tuned to funnel photoexcitations into specific reactant isomers. Thus, upon decoherence, polaritons localize into a chosen isomer, selectively triggering the latter's photoisomerization despite initially being delocalized across all isomers. This result suggests that careful tuning of the cavity resonance is a promising avenue to steer chemical reactions and enhance product selectivity in reaction mixtures.
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Affiliation(s)
- Inki Lee
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Sarah R Melton
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Ding Xu
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Milan Delor
- Department of Chemistry, Columbia University, New York, New York 10027, United States
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Stemo G, Nishiuchi J, Bhakta H, Mao H, Wiesehan G, Xiong W, Katsuki H. Ultrafast Spectroscopy under Vibrational Strong Coupling in Diphenylphosphoryl Azide. J Phys Chem A 2024; 128:1817-1824. [PMID: 38437187 PMCID: PMC10945483 DOI: 10.1021/acs.jpca.3c07847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 01/26/2024] [Accepted: 02/13/2024] [Indexed: 03/06/2024]
Abstract
Strong coupling of cavity photons and molecular vibrations creates vibrational polaritons that have been shown to modify chemical reactivity and alter material properties. While ultrafast spectroscopy of vibrational polaritons has been performed intensively in metal complexes, ultrafast dynamics in vibrationally strongly coupled organic molecules remain unexplored. Here, we report ultrafast pump-probe measurement and two-dimensional infrared spectroscopy in diphenylphosphoryl azide under vibrational strong coupling. Early time oscillatory structures indicate coherent energy exchange between the two polariton modes, which decays in ∼2 ps. We observe a large transient absorptive feature around the lower polariton, which can be explained by the overlapped excited-state absorption and derivative-shaped structures around the lower and upper polaritons. The latter feature is explained by the Rabi splitting contraction, which is ascribed to a reduced population in the ground state. These results reassure the previously reported spectroscopic theory to describe nonlinear spectroscopy of vibrational polaritons. We have also noticed the influence of the complicated layer structure of the cavity mirrors. The penetration of the electric field distribution into the layered structure of the dielectric-mirror cavities can significantly affect the Rabi splitting and the decay time constant of polaritonic systems.
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Affiliation(s)
- Garrek Stemo
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma 630-0192, Japan
| | - Joel Nishiuchi
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma 630-0192, Japan
| | - Harsh Bhakta
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, United States
| | - Haochuan Mao
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, United States
| | - Garret Wiesehan
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, United States
| | - Wei Xiong
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, United States
| | - Hiroyuki Katsuki
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma 630-0192, Japan
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Xiang B, Xiong W. Molecular Polaritons for Chemistry, Photonics and Quantum Technologies. Chem Rev 2024; 124:2512-2552. [PMID: 38416701 PMCID: PMC10941193 DOI: 10.1021/acs.chemrev.3c00662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 01/22/2024] [Accepted: 02/08/2024] [Indexed: 03/01/2024]
Abstract
Molecular polaritons are quasiparticles resulting from the hybridization between molecular and photonic modes. These composite entities, bearing characteristics inherited from both constituents, exhibit modified energy levels and wave functions, thereby capturing the attention of chemists in the past decade. The potential to modify chemical reactions has spurred many investigations, alongside efforts to enhance and manipulate optical responses for photonic and quantum applications. This Review centers on the experimental advances in this burgeoning field. Commencing with an introduction of the fundamentals, including theoretical foundations and various cavity architectures, we discuss outcomes of polariton-modified chemical reactions. Furthermore, we navigate through the ongoing debates and uncertainties surrounding the underpinning mechanism of this innovative method of controlling chemistry. Emphasis is placed on gaining a comprehensive understanding of the energy dynamics of molecular polaritons, in particular, vibrational molecular polaritons─a pivotal facet in steering chemical reactions. Additionally, we discuss the unique capability of coherent two-dimensional spectroscopy to dissect polariton and dark mode dynamics, offering insights into the critical components within the cavity that alter chemical reactions. We further expand to the potential utility of molecular polaritons in quantum applications as well as precise manipulation of molecular and photonic polarizations, notably in the context of chiral phenomena. This discussion aspires to ignite deeper curiosity and engagement in revealing the physics underpinning polariton-modified molecular properties, and a broad fascination with harnessing photonic environments to control chemistry.
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Affiliation(s)
- Bo Xiang
- Department
of Chemistry, School of Science and Research Center for Industries
of the Future, Westlake University, Hangzhou, Zhejiang 310030, China
| | - Wei Xiong
- Department
of Chemistry and Biochemistry, University
of California, San Diego, California 92126, United States
- Materials
Science and Engineering Program, University
of California, San Diego, California 92126, United States
- Department
of Electrical and Computer Engineering, University of California, San
Diego, California 92126, United States
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7
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Thomas PA, Barnes WL. Selection Bias in Strong Coupling Experiments. J Phys Chem Lett 2024; 15:1708-1710. [PMID: 38356453 PMCID: PMC10875671 DOI: 10.1021/acs.jpclett.3c03546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/30/2024] [Accepted: 01/31/2024] [Indexed: 02/16/2024]
Abstract
The strong coupling of light and molecules offers a potential new pathway to modify the properties of photonic modes and molecules. There are many reasons to be optimistic about the prospects of strong coupling; however, progress in this field is currently hindered by challenges in reproducibility, problems associated with differentiating between strong coupling and other effects, and the lack of a clear theoretical model to describe the reported effects. Concerning the question of differentiating between strong coupling and other possible mechanisms when examining experimental data, here, we show how cognitive bias can lead us to place undue emphasis on a given interpretation of unsystematic experimental data. We hope that this Viewpoint will, where appropriate, help readers to plan strong coupling experiments more carefully and evaluate the significance of the data obtained from them.
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Affiliation(s)
- Philip A. Thomas
- Department of Physics and Astronomy, University of Exeter, Exeter EX4 4QL, United
Kingdom
| | - William L. Barnes
- Department of Physics and Astronomy, University of Exeter, Exeter EX4 4QL, United
Kingdom
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