1
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Cohen G, Haber JB, Neaton JB, Qiu DY, Refaely-Abramson S. Phonon-Driven Femtosecond Dynamics of Excitons in Crystalline Pentacene from First Principles. PHYSICAL REVIEW LETTERS 2024; 132:126902. [PMID: 38579218 DOI: 10.1103/physrevlett.132.126902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 08/24/2023] [Accepted: 02/11/2024] [Indexed: 04/07/2024]
Abstract
Nonradiative exciton relaxation processes are critical for energy transduction and transport in optoelectronic materials, but how these processes are connected to the underlying crystal structure and the associated electron, exciton, and phonon band structures, as well as the interactions of all these particles, is challenging to understand. Here, we present a first-principles study of exciton-phonon relaxation pathways in pentacene, a paradigmatic molecular crystal and optoelectronic semiconductor. We compute the momentum- and band-resolved exciton-phonon interactions, and use them to analyze key scattering channels. We find that both exciton intraband scattering and interband scattering to parity-forbidden dark states occur on the same ∼100 fs timescale as a direct consequence of the longitudinal-transverse splitting of the bright exciton band. Consequently, exciton-phonon scattering exists as a dominant nonradiative relaxation channel in pentacene. We further show how the propagation of an exciton wave packet is connected with crystal anisotropy, which gives rise to the longitudinal-transverse exciton splitting and concomitant anisotropic exciton and phonon dispersions. Our results provide a framework for understanding the role of exciton-phonon interactions in exciton nonradiative lifetimes in molecular crystals and beyond.
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Affiliation(s)
- Galit Cohen
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Jonah B Haber
- Department of Physics, University of California Berkeley, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Jeffrey B Neaton
- Department of Physics, University of California Berkeley, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Kavli Energy Nanosciences Institute at Berkeley, Berkeley, California 94720, USA
| | - Diana Y Qiu
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06520, USA
| | - Sivan Refaely-Abramson
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel
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2
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Unger F, Lepple D, Asbach M, Craciunescu L, Zeiser C, Kandolf AF, Fišer Z, Hagara J, Hagenlocher J, Hiller S, Haug S, Deutsch M, Grüninger P, Novák J, Bettinger HF, Broch K, Engels B, Schreiber F. Optical Absorption Properties in Pentacene/Tetracene Solid Solutions. J Phys Chem A 2024; 128:747-760. [PMID: 38232326 DOI: 10.1021/acs.jpca.3c06737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Modifying the optical and electronic properties of crystalline organic thin films is of great interest for improving the performance of modern organic semiconductor devices. Therein, the statistical mixing of molecules to form a solid solution provides an opportunity to fine-tune optical and electronic properties. Unfortunately, the diversity of intermolecular interactions renders mixed organic crystals highly complex, and a holistic picture is still lacking. Here, we report a study of the optical absorption properties in solid solutions of pentacene and tetracene, two prototypical organic semiconductors. In the mixtures, the optical properties can be continuously modified by statistical mixing at the molecular level. Comparison with time-dependent density functional theory calculations on occupationally disordered clusters unravels the electronic origin of the low energy optical transitions. The disorder partially relaxes the selection rules, leading to additional optical transitions that manifest as optical broadening. Furthermore, the contribution of diabatic charge-transfer states is modified in the mixtures, reducing the observed splitting in the 0-0 vibronic transition. Additional comparisons with other blended systems generalize our results and indicate that changes in the polarizability of the molecular environment in organic thin-film blends induce shifts in the absorption spectrum.
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Affiliation(s)
- Frederik Unger
- Institute of Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Daniel Lepple
- Institute of Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Maximilian Asbach
- Julius-Maximilian University Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Luca Craciunescu
- Julius-Maximilian University Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS Scotland, U.K
| | - Clemens Zeiser
- Institute of Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Andreas F Kandolf
- Institute of Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
- Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Zbyněk Fišer
- Department of Condensed Matter Physics (UFKL), Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic
| | - Jakub Hagara
- Institute of Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Jan Hagenlocher
- Institute of Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Stefan Hiller
- Institute of Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Sara Haug
- Institute of Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Marian Deutsch
- Julius-Maximilian University Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Peter Grüninger
- Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Jiří Novák
- Department of Condensed Matter Physics (UFKL), Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic
| | - Holger F Bettinger
- Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Katharina Broch
- Institute of Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Bernd Engels
- Julius-Maximilian University Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Frank Schreiber
- Institute of Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
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3
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Günder D, Axt M, Witte G. Heteroepitaxy in Organic/TMD Hybrids and Challenge to Achieve it for TMD Monolayers: The Case of Pentacene on WS 2 and WSe 2. ACS APPLIED MATERIALS & INTERFACES 2024; 16:1911-1920. [PMID: 38154080 DOI: 10.1021/acsami.3c15829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2023]
Abstract
The intriguing photophysical properties of monolayer stacks of different transition-metal dichalcogenides (TMDs), revealing rich exciton physics including interfacial and moiré excitons, have recently prompted an extension of similar investigations to hybrid systems of TMDs and organic films, as the latter combine large photoabsorption cross sections with the ability to tailor energy levels by targeted synthesis. To go beyond single-molecule photoexcitations and exploit the excitonic signatures of organic solids, crystalline molecular films are required. Moreover, a defined registry on the substrate, ideally an epitaxy, is desirable to also achieve an excitonic coupling in momentum space. This poses a certain challenge as excitonic dipole moments of organic films are closely related to the molecular orientation and film structure, which critically depend on the support roughness. Using X-ray diffraction, optical polarization, and atomic force microscopy, we analyzed the structure of pentacene (PEN) multilayer films grown on WSe2(001) and WS2(001) and identified an epitaxial alignment. While (022)-oriented PEN films are formed on both substrates, their azimuthal orientations are quite different, showing an alignment of the molecular L-axis along the ⟨ 110 ⟩ WSe 2 and ⟨ 100 ⟩ WS 2 directions. This intrinsic epitaxial PEN growth depends, however, sensitively on the substrates surface quality. While it occurs on exfoliated TMD single crystals and multilayer flakes, it is hardly found on exfoliated monolayers, which often exhibit bubbles and wrinkles. This enhances the surface roughness and results in (001)-oriented PEN films with upright molecular orientation but without any azimuthal alignment. However, monolayer flakes can be smoothed by AFM operated in contact mode or by transferring to ultrasmooth substrates such as hBN, which again yields epitaxial PEN films. As different PEN orientations result in different characteristic film morphologies (elongated mesa islands vs pyramidal dendrites), which can be easily distinguished by AFM or optical microscopy, this provides a simple means to judge the roughness of the used TMD surface.
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Affiliation(s)
- Darius Günder
- Molekulare Festkörperphysik, Philipps-Universität Marburg, Marburg 35032, Germany
| | - Marleen Axt
- Oberflächenphysik, Philipps-Universität Marburg, Marburg 35032, Germany
| | - Gregor Witte
- Molekulare Festkörperphysik, Philipps-Universität Marburg, Marburg 35032, Germany
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4
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Craciunescu L, Asbach M, Wirsing S, Hammer S, Unger F, Broch K, Schreiber F, Witte G, Dreuw A, Tegeder P, Fantuzzi F, Engels B. Cluster-Based Approach Utilizing Optimally Tuned TD-DFT to Calculate Absorption Spectra of Organic Semiconductor Thin Films. J Chem Theory Comput 2023; 19:9369-9387. [PMID: 38073092 DOI: 10.1021/acs.jctc.3c01107] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
The photophysics of organic semiconductor (OSC) thin films or crystals has garnered significant attention in recent years since a comprehensive theoretical understanding of the various processes occurring upon photoexcitation is crucial for assessing the efficiency of OSC materials. To date, research in this area has relied on methods using Frenkel-Holstein Hamiltonians, calculations of the GW-Bethe-Salpeter equation with periodic boundaries, or cluster-based approaches using quantum chemical methods, with each of the three approaches having distinct advantages and disadvantages. In this work, we introduce an optimally tuned, range-separated time-dependent density functional theory approach to accurately reproduce the total and polarization-resolved absorption spectra of pentacene, tetracene, and perylene thin films, all representative OSC materials. Our approach achieves excellent agreement with experimental data (mostly ≤0.1 eV) when combined with the utilization of clusters comprising multiple monomers and a standard polarizable continuum model to simulate the thin-film environment. Our protocol therefore addresses a major drawback of cluster-based approaches and makes them attractive tools for OSC investigations. Its key advantages include its independence from external, system-specific fitting parameters and its straightforward application with well-known quantum chemical program codes. It demonstrates how chemical intuition can help to reduce computational cost and still arrive at chemically meaningful and almost quantitative results.
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Affiliation(s)
- Luca Craciunescu
- Institut für Physikalische und Theoretische Chemie, Julius-Maximilians-Universität Würzburg, Emil-Fischer-Str. 42, 97074 Würzburg, Germany
- Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS Scotland, U.K
| | - Maximilian Asbach
- Institut für Physikalische und Theoretische Chemie, Julius-Maximilians-Universität Würzburg, Emil-Fischer-Str. 42, 97074 Würzburg, Germany
| | - Sara Wirsing
- Institut für Physikalische und Theoretische Chemie, Julius-Maximilians-Universität Würzburg, Emil-Fischer-Str. 42, 97074 Würzburg, Germany
| | - Sebastian Hammer
- Experimentelle Physik VI, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Center for the Physics of Materials, Department of Physics and Department of Chemistry, McGill University, 801 Sherbrooke St. W, Montreal, H3A 2K6 Québec, Canada
| | - Frederik Unger
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Katharina Broch
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Frank Schreiber
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Gregor Witte
- Molekulare Festkörperphysik, Philipps-Universität Marburg, 35032 Marburg, Germany
| | - Andreas Dreuw
- Interdisziplinäres Zentrum für Wissenschaftliches Rechnen, Universität Heidelberg, Im Neuenheimer Feld 205, 69120 Heidelberg, Germany
| | - Petra Tegeder
- Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
| | - Felipe Fantuzzi
- School of Chemistry and Forensic Science, University of Kent, Park Wood Rd, CT2 7NH Canterbury, U.K
| | - Bernd Engels
- Institut für Physikalische und Theoretische Chemie, Julius-Maximilians-Universität Würzburg, Emil-Fischer-Str. 42, 97074 Würzburg, Germany
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5
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Müller K, Schellhammer KS, Gräßler N, Debnath B, Liu F, Krupskaya Y, Leo K, Knupfer M, Ortmann F. Directed exciton transport highways in organic semiconductors. Nat Commun 2023; 14:5599. [PMID: 37699907 PMCID: PMC10497625 DOI: 10.1038/s41467-023-41044-9] [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: 06/02/2022] [Accepted: 08/21/2023] [Indexed: 09/14/2023] Open
Abstract
Exciton bandwidths and exciton transport are difficult to control by material design. We showcase the intriguing excitonic properties in an organic semiconductor material with specifically tailored functional groups, in which extremely broad exciton bands in the near-infrared-visible part of the electromagnetic spectrum are observed by electron energy loss spectroscopy and theoretically explained by a close contact between tightly packing molecules and by their strong interactions. This is induced by the donor-acceptor type molecular structure and its resulting crystal packing, which induces a remarkable anisotropy that should lead to a strongly directed transport of excitons. The observations and detailed understanding of the results yield blueprints for the design of molecular structures in which similar molecular features might be used to further explore the tunability of excitonic bands and pave a way for organic materials with strongly enhanced transport and built-in control of the propagation direction.
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Affiliation(s)
- Kai Müller
- Center for Advancing Electronics Dresden, Technische Universität Dresden, 01062, Dresden, Germany
- Institut für Theoretische Physik, Technische Universität Dresden, 01062, Dresden, Germany
| | - Karl S Schellhammer
- Center for Advancing Electronics Dresden, Technische Universität Dresden, 01062, Dresden, Germany
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics, Technische Universität Dresden, 01062, Dresden, Germany
| | - Nico Gräßler
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics, Technische Universität Dresden, 01062, Dresden, Germany
- Leibniz Institute for Solid State and Materials Research Dresden, Helmholtzstr. 20, 01069, Dresden, Germany
| | - Bipasha Debnath
- Leibniz Institute for Solid State and Materials Research Dresden, Helmholtzstr. 20, 01069, Dresden, Germany
| | - Fupin Liu
- Leibniz Institute for Solid State and Materials Research Dresden, Helmholtzstr. 20, 01069, Dresden, Germany
| | - Yulia Krupskaya
- Leibniz Institute for Solid State and Materials Research Dresden, Helmholtzstr. 20, 01069, Dresden, Germany
| | - Karl Leo
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics, Technische Universität Dresden, 01062, Dresden, Germany
| | - Martin Knupfer
- Leibniz Institute for Solid State and Materials Research Dresden, Helmholtzstr. 20, 01069, Dresden, Germany
| | - Frank Ortmann
- Center for Advancing Electronics Dresden, Technische Universität Dresden, 01062, Dresden, Germany.
- Department of Chemistry, TUM School of Natural Sciences, Technische Universität München, Lichtenbergstr. 4, 85748, Garching b. München, Germany.
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6
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Theurer CP, Laible F, Tang J, Broch K, Fleischer M, Schreiber F. Strong light-matter coupling in pentacene thin films on plasmonic arrays. NANOSCALE 2023. [PMID: 37387269 DOI: 10.1039/d3nr01108a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/01/2023]
Abstract
Utilizing strong light-matter coupling is an elegant and powerful way to modify the energy landscapes of excited states of organic semiconductors. Consequently, the chemical and photophysical properties of these organic semiconductors can be influenced without the need of chemical modification but simply by implementing them in optical microcavities. This has so far mostly been shown in Fabry-Pérot cavities and with organic single crystals or diluted molecules in a host matrix. Here, we demonstrate strong, simultaneous coupling of the two Davydov transitions in polycrystalline pentacene thin films to surface lattice resonances supported by open cavities made of silver nanoparticle arrays. Such thin films are more easily fabricated and, together with the open architecture, more suitable for device applications.
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Affiliation(s)
- Christoph P Theurer
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
| | - Florian Laible
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
| | - Jia Tang
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
| | - Katharina Broch
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
- Center for Light-Matter Interaction, Sensors & Analytics (LISA+), Universität Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany
| | - Monika Fleischer
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
- Center for Light-Matter Interaction, Sensors & Analytics (LISA+), Universität Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany
| | - Frank Schreiber
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
- Center for Light-Matter Interaction, Sensors & Analytics (LISA+), Universität Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany
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7
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Thompson JJP, Lumsargis V, Feierabend M, Zhao Q, Wang K, Dou L, Huang L, Malic E. Interlayer exciton landscape in WS 2/tetracene heterostructures. NANOSCALE 2023; 15:1730-1738. [PMID: 36594632 DOI: 10.1039/d2nr02055f] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The vertical stacking of two-dimensional materials into heterostructures gives rise to a plethora of intriguing optoelectronic properties and presents an unprecedented potential for technological development. While much progress has been made combining different monolayers of transition metal dichalcogenides (TMDs), little is known about TMD-based heterostructures including organic layers of molecules. Here, we present a joint theory-experiment study on a TMD/tetracene heterostructure demonstrating clear signatures of spatially separated interlayer excitons in low temperature photoluminescence spectra. Here, the Coulomb-bound electrons and holes are localized either in the TMD or in the molecule layer, respectively. We reveal both in theory and experiment signatures of the entire intra- and interlayer exciton landscape in the photoluminescence spectra. In particular, we find both in theory and experiment a pronounced transfer of intensity from the intralayer TMD exciton to a series of energetically lower interlayer excitons with decreasing temperature. In addition, we find signatures of phonon-sidebands stemming from these interlayer exciton states. Our findings shed light on the microscopic nature of interlayer excitons in TMD/molecule heterostructures and could have important implications for technological applications of these materials.
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Affiliation(s)
- Joshua J P Thompson
- Department of Physics, Philipps-Universität Marburg, 35037 Marburg, Germany.
| | - Victoria Lumsargis
- Department of Chemistry, Purdue University, West Lafayette, Indiana, 47907, USA
| | - Maja Feierabend
- Department of Physics, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Quichen Zhao
- Department of Chemistry, Purdue University, West Lafayette, Indiana, 47907, USA
- State Key Laboratory of Superhard Materials, Jilin University, Changchun, Jilin, 130012, China
| | - Kang Wang
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana, 47907, USA
| | - Letian Dou
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana, 47907, USA
| | - Libai Huang
- Department of Chemistry, Purdue University, West Lafayette, Indiana, 47907, USA
| | - Ermin Malic
- Department of Physics, Philipps-Universität Marburg, 35037 Marburg, Germany.
- Department of Physics, Chalmers University of Technology, 412 96 Gothenburg, Sweden
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8
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Wang Z, Gan Y, Du Q, Li S, Liu Y, Wang W. Morphology-Dependent Optoelectronic Properties of Pentacene Nanoribbon and Nanosheet Crystallite. MATERIALS (BASEL, SWITZERLAND) 2023; 16:557. [PMID: 36676294 PMCID: PMC9864833 DOI: 10.3390/ma16020557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/01/2023] [Accepted: 01/03/2023] [Indexed: 06/17/2023]
Abstract
Organic, single crystals have emerged as unique optoelectrical materials due to their highly ordered structure and low defects. In this work, pentacene nanoribbons and nanosheets were selectively fabricated by controlling their growth temperature. The results show that their photoluminescence (PL) activity and electrical properties were strongly dependent on their geometrical morphology and molecular stacking mode such as the degree of π-orbital overlap and intermolecular interaction. The pentacene nanoribbon crystal exhibited a higher PL intensity compared with the nanosheet configuration; conversely, its electrical conductivity was poor. The low-temperature PL measurement indicated that there are stronger π-π stacking interactions in the nanosheet crystal than in the nanoribbon crystal, leading to exciton quenching and higher conductivity. Our study demonstrated that a unique optoelectronic property of organic crystals can be obtained by controlling the crystal's morphology, which offers potential guidance for the future design and development of organic crystal optoelectronics.
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Affiliation(s)
- Zhifeng Wang
- School of Physical Science and Information Technology, Liaocheng University, Liaocheng 252059, China
- Shandong Provincial Key Laboratory of Optical Communication Science and Technology, Liaocheng 252059, China
| | - Yuquan Gan
- School of Physical Science and Information Technology, Liaocheng University, Liaocheng 252059, China
- Shandong Provincial Key Laboratory of Optical Communication Science and Technology, Liaocheng 252059, China
| | - Qianqian Du
- School of Physical Science and Information Technology, Liaocheng University, Liaocheng 252059, China
- Shandong Provincial Key Laboratory of Optical Communication Science and Technology, Liaocheng 252059, China
| | - Shuhong Li
- School of Physical Science and Information Technology, Liaocheng University, Liaocheng 252059, China
- Shandong Provincial Key Laboratory of Optical Communication Science and Technology, Liaocheng 252059, China
| | - Yunlong Liu
- School of Physical Science and Information Technology, Liaocheng University, Liaocheng 252059, China
- Shandong Provincial Key Laboratory of Optical Communication Science and Technology, Liaocheng 252059, China
| | - Wenjun Wang
- School of Physical Science and Information Technology, Liaocheng University, Liaocheng 252059, China
- Shandong Provincial Key Laboratory of Optical Communication Science and Technology, Liaocheng 252059, China
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9
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Markeev PA, Najafidehaghani E, Samu GF, Sarosi K, Kalkan SB, Gan Z, George A, Reisner V, Mogyorosi K, Chikan V, Nickel B, Turchanin A, de Jong MP. Exciton Dynamics in MoS 2-Pentacene and WSe 2-Pentacene Heterojunctions. ACS NANO 2022; 16:16668-16676. [PMID: 36178781 PMCID: PMC9620401 DOI: 10.1021/acsnano.2c06144] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 09/28/2022] [Indexed: 06/16/2023]
Abstract
We measured the exciton dynamics in van der Waals heterojunctions of transition metal dichalcogenides (TMDCs) and organic semiconductors (OSs). TMDCs and OSs are semiconducting materials with rich and highly diverse optical and electronic properties. Their heterostructures, exhibiting van der Waals bonding at their interfaces, can be utilized in the field of optoelectronics and photovoltaics. Two types of heterojunctions, MoS2-pentacene and WSe2-pentacene, were prepared by layer transfer of 20 nm pentacene thin films as well as MoS2 and WSe2 monolayer crystals onto Au surfaces. The samples were studied by means of transient absorption spectroscopy in the reflectance mode. We found that A-exciton decay by hole transfer from MoS2 to pentacene occurs with a characteristic time of 21 ± 3 ps. This is slow compared to previously reported hole transfer times of 6.7 ps in MoS2-pentacene junctions formed by vapor deposition of pentacene molecules onto MoS2 on SiO2. The B-exciton decay in WSe2 shows faster hole transfer rates for WSe2-pentacene heterojunctions, with a characteristic time of 7 ± 1 ps. The A-exciton in WSe2 also decays faster due to the presence of a pentacene overlayer; however, fitting the decay traces did not allow for the unambiguous assignment of the associated decay time. Our work provides important insights into excitonic dynamics in the growing field of TMDC-OS heterojunctions.
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Affiliation(s)
- Pavel A. Markeev
- MESA+
Institute for Nanotechnology, University
of Twente, 7500 AEEnschede, The Netherlands
| | - Emad Najafidehaghani
- Institute
of Physical Chemistry, Abbe Center of Photonics, Friedrich Schiller University, 07743Jena, Germany
| | - Gergely F. Samu
- ELI-ALPS, ELI-HU Non-Profit Ltd., Wolfgang Sandner 3, SzegedH-6728, Hungary
| | - Krisztina Sarosi
- ELI-ALPS, ELI-HU Non-Profit Ltd., Wolfgang Sandner 3, SzegedH-6728, Hungary
| | - Sirri Batuhan Kalkan
- Faculty
of Physics and CeNS, Ludwig-Maximilians-Universität, Geschwister-Scholl-Platz 1, 80539Munich, Germany
| | - Ziyang Gan
- Institute
of Physical Chemistry, Abbe Center of Photonics, Friedrich Schiller University, 07743Jena, Germany
| | - Antony George
- Institute
of Physical Chemistry, Abbe Center of Photonics, Friedrich Schiller University, 07743Jena, Germany
| | - Veronika Reisner
- Faculty
of Physics and CeNS, Ludwig-Maximilians-Universität, Geschwister-Scholl-Platz 1, 80539Munich, Germany
| | - Karoly Mogyorosi
- ELI-ALPS, ELI-HU Non-Profit Ltd., Wolfgang Sandner 3, SzegedH-6728, Hungary
| | - Viktor Chikan
- ELI-ALPS, ELI-HU Non-Profit Ltd., Wolfgang Sandner 3, SzegedH-6728, Hungary
- Department
of Chemistry, Kansas State University, 213 CBC Building, Manhattan, Kansas66506-0401, United States
| | - Bert Nickel
- Faculty
of Physics and CeNS, Ludwig-Maximilians-Universität, Geschwister-Scholl-Platz 1, 80539Munich, Germany
| | - Andrey Turchanin
- Institute
of Physical Chemistry, Abbe Center of Photonics, Friedrich Schiller University, 07743Jena, Germany
| | - Michel P. de Jong
- MESA+
Institute for Nanotechnology, University
of Twente, 7500 AEEnschede, The Netherlands
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10
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Craciunescu L, Wirsing S, Hammer S, Broch K, Dreuw A, Fantuzzi F, Sivanesan V, Tegeder P, Engels B. Accurate Polarization-Resolved Absorption Spectra of Organic Semiconductor Thin Films Using First-Principles Quantum-Chemical Methods: Pentacene as a Case Study. J Phys Chem Lett 2022; 13:3726-3731. [PMID: 35442698 DOI: 10.1021/acs.jpclett.2c00573] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Theoretical studies using clusters as model systems have been extremely successful in explaining various photophysical phenomena in organic semiconductor (OSC) thin films. But they have not been able to satisfactorily simulate total and polarization-resolved absorption spectra of OSCs so far. In this work, we demonstrate that accurate spectra are predicted by time-dependent density functional theory (TD-DFT) when the employed cluster reflects the symmetry of the crystal structure and all monomers feel the same environment. Additionally, long-range corrected optimal tuned functionals are mandatory. For pentacene thin films, the computed electronic spectra for thin films then reach an impressive accuracy compared with experimental data with a deviation of less than 0.1 eV. This allows for accurate peak assignments and mechanistic studies, which paves the way for a comprehensive understanding of OSCs using an affordable and easy-to-use cluster approach.
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Affiliation(s)
- Luca Craciunescu
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Emil-Fischer-Strasse 42, 97074 Würzburg, Germany
| | - Sara Wirsing
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Emil-Fischer-Strasse 42, 97074 Würzburg, Germany
| | - Sebastian Hammer
- Experimentelle Physik VI, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Center for the Physics of Materials, Department of Physics and Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, QC H3A 2K6, Canada
| | - Katharina Broch
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Andreas Dreuw
- Interdisziplinäres Zentrum für Wissenschaftliches Rechnen, Universität Heidelberg, Im Neuenheimer Feld 205, 69120 Heidelberg, Germany
| | - Felipe Fantuzzi
- School of Physical Sciences, Ingram Building, University of Kent, Park Wood Road, Canterbury CT2 7NH, U.K
| | - Vipilan Sivanesan
- Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
| | - Petra Tegeder
- Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
| | - Bernd Engels
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Emil-Fischer-Strasse 42, 97074 Würzburg, Germany
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11
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Altman AR, Refaely-Abramson S, da Jornada FH. Identifying Hidden Intracell Symmetries in Molecular Crystals and Their Impact for Multiexciton Generation. J Phys Chem Lett 2022; 13:747-753. [PMID: 35029407 DOI: 10.1021/acs.jpclett.1c03540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Organic molecular crystals are appealing for next-generation optoelectronic applications due to their multiexciton generation processes that can increase the efficiency of photovoltaic devices. However, a general understanding of how crystal structures affect these processes is lacking, requiring computationally demanding calculations for each material. Here we present an approach to understand and classify organic crystals and elucidate multiexciton processes. We show that organic crystals that are composed of two sublattices are well-approximated by effective fictitious systems of higher translational symmetry. Within this framework, we derive hidden selection rules in crystal pentacene and predict that the bulk polymorph supports fast Coulomb-mediated singlet fission with a transition rate about 2 orders of magnitude faster than that of the thin-film polymorph, a result confirmed with many-body perturbation theory calculations. Our approach is based on density-functional theory calculations and provides design principles for the experimental and computational discovery of new materials with tailored excitonic properties.
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Affiliation(s)
- Aaron R Altman
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Sivan Refaely-Abramson
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Felipe H da Jornada
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
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12
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Günder D, Valencia AM, Guerrini M, Breuer T, Cocchi C, Witte G. Polarization Resolved Optical Excitation of Charge-Transfer Excitons in PEN:PFP Cocrystalline Films: Limits of Nonperiodic Modeling. J Phys Chem Lett 2021; 12:9899-9905. [PMID: 34610238 DOI: 10.1021/acs.jpclett.1c02761] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Charge-transfer excitons (CTXs) at organic donor/acceptor interfaces are considered important intermediates for charge separation in photovoltaic devices. Crystalline model systems provide microscopic insights into the nature of such states as they enable microscopic structure-property investigations. Here, we use angular-resolved UV/vis absorption spectroscopy to characterize the CTXs of crystalline pentacene:perfluoro-pentacene (PEN:PFP) films allowing determination of the polarization of this state. This analysis is complemented by first-principles many-body calculations, performed on the three-dimensional PEN:PFP cocrystal, which confirm that the lowest-energy excitation is a CTX. Analogous simulations performed on bimolecular clusters are unable to reproduce this state. We ascribe this failure to the lack of long-range interactions and wave function periodicity in these cluster calculations, which appear to remain a valid tool for modeling properties of organic materials ruled by local intermolecular couplings.
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Affiliation(s)
- Darius Günder
- Philipps-Universität Marburg, Molekulare Festkörperphysik, 35032 Marburg, Germany
| | - Ana M Valencia
- Carl von Ossietzky Universität Oldenburg, Institute of Physics, Carl-von-Ossietzky-Straße 9, 26129 Oldenburg, Germany
| | - Michele Guerrini
- Carl von Ossietzky Universität Oldenburg, Institute of Physics, Carl-von-Ossietzky-Straße 9, 26129 Oldenburg, Germany
| | - Tobias Breuer
- Philipps-Universität Marburg, Molekulare Festkörperphysik, 35032 Marburg, Germany
| | - Caterina Cocchi
- Carl von Ossietzky Universität Oldenburg, Institute of Physics, Carl-von-Ossietzky-Straße 9, 26129 Oldenburg, Germany
- Humboldt-Universität zu Berlin, Physics Department and IRIS Adlershof, Zum Großen Windkanal 2, 12489 Berlin, Germany
| | - Gregor Witte
- Philipps-Universität Marburg, Molekulare Festkörperphysik, 35032 Marburg, Germany
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13
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Shunak L, Adeniran O, Voscoboynik G, Liu ZF, Refaely-Abramson S. Exciton Modulation in Perylene-Based Molecular Crystals Upon Formation of a Metal-Organic Interface From Many-Body Perturbation Theory. Front Chem 2021; 9:743391. [PMID: 34616715 PMCID: PMC8488370 DOI: 10.3389/fchem.2021.743391] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Accepted: 09/07/2021] [Indexed: 11/22/2022] Open
Abstract
Excited-state processes at organic-inorganic interfaces consisting of molecular crystals are essential in energy conversion applications. While advances in experimental methods allow direct observation and detection of exciton transfer across such junctions, a detailed understanding of the underlying excitonic properties due to crystal packing and interface structure is still largely lacking. In this work, we use many-body perturbation theory to study structure-property relations of excitons in molecular crystals upon adsorption on a gold surface. We explore the case of the experimentally-studied octyl perylene diimide (C8-PDI) as a prototypical system, and use the GW and Bethe-Salpeter equation (BSE) approach to quantify the change in quasiparticle and exciton properties due to intermolecular and substrate screening. Our findings provide a close inspection of both local and environmental structural effects dominating the excitation energies and the exciton binding and nature, as well as their modulation upon the metal-organic interface composition.
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Affiliation(s)
- Liran Shunak
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, Israel
| | - Olugbenga Adeniran
- Department of Chemistry, Wayne State University, Detroit, MI, United States
| | - Guy Voscoboynik
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, Israel
| | - Zhen-Fei Liu
- Department of Chemistry, Wayne State University, Detroit, MI, United States
| | - Sivan Refaely-Abramson
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, Israel
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14
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Pham NNT, Han SH, Park JS, Lee SG. Optical and Electronic Properties of Organic NIR-II Fluorophores by Time-Dependent Density Functional Theory and Many-Body Perturbation Theory: GW-BSE Approaches. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:2293. [PMID: 34578610 PMCID: PMC8466807 DOI: 10.3390/nano11092293] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/30/2021] [Accepted: 09/01/2021] [Indexed: 11/16/2022]
Abstract
Organic-molecule fluorophores with emission wavelengths in the second near-infrared window (NIR-II, 1000-1700 nm) have attracted substantial attention in the life sciences and in biomedical applications because of their excellent resolution and sensitivity. However, adequate theoretical levels to provide efficient and accurate estimations of the optical and electronic properties of organic NIR-II fluorophores are lacking. The standard approach for these calculations has been time-dependent density functional theory (TDDFT). However, the size and large excitonic energies of these compounds pose challenges with respect to computational cost and time. In this study, we used the GW approximation combined with the Bethe-Salpeter equation (GW-BSE) implemented in many-body perturbation theory approaches based on density functional theory. This method was used to perform calculations of the excited states of two NIR molecular fluorophores (BTC980 and BTC1070), going beyond TDDFT. In this study, the optical absorption spectra and frontier molecular orbitals of these compounds were compared using TDDFT and GW-BSE calculations. The GW-BSE estimates showed excellent agreement with previously reported experimental results.
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Affiliation(s)
- Nguyet N. T. Pham
- School of Chemical Engineering, Pusan National University, Busan 46241, Korea; (N.N.T.P.); (S.H.H.)
| | - Seong Hun Han
- School of Chemical Engineering, Pusan National University, Busan 46241, Korea; (N.N.T.P.); (S.H.H.)
| | - Jong S. Park
- School of Chemical Engineering, Pusan National University, Busan 46241, Korea; (N.N.T.P.); (S.H.H.)
- Department of Organic Material Science and Engineering, Pusan National University, Busan 46241, Korea
| | - Seung Geol Lee
- School of Chemical Engineering, Pusan National University, Busan 46241, Korea; (N.N.T.P.); (S.H.H.)
- Department of Organic Material Science and Engineering, Pusan National University, Busan 46241, Korea
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15
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Sun K, Liu X, Hu W, Zhang M, Long G, Zhao Y. Singlet fission dynamics and optical spectra of pentacene and its derivatives. Phys Chem Chem Phys 2021; 23:12654-12667. [PMID: 34036985 DOI: 10.1039/d1cp00563d] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A multimode Brownian oscillator model is employed to investigate the absorption spectra of pentacene and its derivatives in solution and thin films. Excellent agreement has been obtained between simulated and measured absorption spectra. Furthermore, using parameters obtained from fitting the absorption spectra of these pentacene derivatives, the singlet fission dynamics and two-dimensional electronic spectra of an ab initio Hamiltonian are investigated by Dirac-Frenkel time-dependent variation with multiple Davydov trial states. It is found that the periodic wave packet motion induced in the displaced excited state, and the accompanying vibrational relaxation, can be visualized by two-dimensional electronic spectra at short times.
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Affiliation(s)
- Kewei Sun
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, China
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16
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Seiler H, Krynski M, Zahn D, Hammer S, Windsor YW, Vasileiadis T, Pflaum J, Ernstorfer R, Rossi M, Schwoerer H. Nuclear dynamics of singlet exciton fission in pentacene single crystals. SCIENCE ADVANCES 2021; 7:7/26/eabg0869. [PMID: 34172443 PMCID: PMC8232917 DOI: 10.1126/sciadv.abg0869] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 05/14/2021] [Indexed: 05/22/2023]
Abstract
Singlet exciton fission (SEF) is a key process for developing efficient optoelectronic devices. An aspect rarely probed directly, yet with tremendous impact on SEF properties, is the nuclear structure and dynamics involved in this process. Here, we directly observe the nuclear dynamics accompanying the SEF process in single crystal pentacene using femtosecond electron diffraction. The data reveal coherent atomic motions at 1 THz, incoherent motions, and an anisotropic lattice distortion representing the polaronic character of the triplet excitons. Combining molecular dynamics simulations, time-dependent density-functional theory, and experimental structure factor analysis, the coherent motions are identified as collective sliding motions of the pentacene molecules along their long axis. Such motions modify the excitonic coupling between adjacent molecules. Our findings reveal that long-range motions play a decisive part in the electronic decoupling of the electronically correlated triplet pairs and shed light on why SEF occurs on ultrafast time scales.
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Affiliation(s)
- Hélène Seiler
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin 14195, Germany.
| | - Marcin Krynski
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin 14195, Germany
| | - Daniela Zahn
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin 14195, Germany
| | - Sebastian Hammer
- Julius-Maximilians-Universität, Experimentelle Physik VI, Am Hubland, 97074 Würzburg, Germany.
| | | | | | - Jens Pflaum
- Julius-Maximilians-Universität, Experimentelle Physik VI, Am Hubland, 97074 Würzburg, Germany
- Bayerisches Zentrum für Angewandte Energieforschung, Magdalene-Schoch-Straße 3, 97074 Würzburg, Germany
| | - Ralph Ernstorfer
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin 14195, Germany
| | - Mariana Rossi
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin 14195, Germany.
- Max-Planck-Institut für Struktur und Dynamik der Materie, 22761 Hamburg, Germany
| | - Heinrich Schwoerer
- Max-Planck-Institut für Struktur und Dynamik der Materie, 22761 Hamburg, Germany.
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17
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Funke S, Duwe M, Balzer F, Thiesen PH, Hingerl K, Schiek M. Determining the Dielectric Tensor of Microtextured Organic Thin Films by Imaging Mueller Matrix Ellipsometry. J Phys Chem Lett 2021; 12:3053-3058. [PMID: 33739845 PMCID: PMC8041376 DOI: 10.1021/acs.jpclett.1c00317] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 03/16/2021] [Indexed: 06/12/2023]
Abstract
Polycrystalline textured thin films with distinct pleochroism and birefringence comprising oriented rotational domains of the orthorhombic polymorph of an anilino squaraine with isobutyl side chains (SQIB) are analyzed by imaging Mueller matrix ellipsometry to obtain the biaxial dielectric tensor. Simultaneous fitting of transmission and oblique incidence reflection Mueller matrix scans combined with the spatial resolution of an optical microscope allows to accurately determine the full biaxial dielectric tensor from a single crystallographic sample orientation. Oscillator dispersion relations model well the dielectric tensor components. Strong intermolecular interactions cause the real permittivity for all three directions to become strongly negative near the excitonic resonances, which is appealing for nanophotonic applications.
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Affiliation(s)
- Sebastian Funke
- Accurion
GmbH, Stresemannstr. 30, D-37079 Göttingen, Germany
| | - Matthias Duwe
- Accurion
GmbH, Stresemannstr. 30, D-37079 Göttingen, Germany
| | - Frank Balzer
- Centre
for Photonics Engineering, University of
Southern Denmark, Alsion 2, DK-6400 Sønderborg, Denmark
| | | | - Kurt Hingerl
- Center
for Surface- and Nanoanalytics, Johannes
Kepler University, Altenbergerstr. 69, A-4040 Linz, Austria
| | - Manuela Schiek
- Institute
of Physics, University of Oldenburg, Carl-von-Ossietzky-Str. 9-11, D-26129 Oldenburg, Germany
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18
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Krumland J, Valencia AM, Cocchi C. Exploring organic semiconductors in solution: the effects of solvation, alkylization, and doping. Phys Chem Chem Phys 2021; 23:4841-4855. [PMID: 33605967 DOI: 10.1039/d0cp06085b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The first-principles simulation of the electronic structure of organic semiconductors in solution poses a number of challenges that are not trivial to address simultaneously. In this work, we investigate the effects and the mutual interplay of solvation, alkylization, and doping on the structural, electronic, and optical properties of sexithiophene, a representative organic semiconductor molecule. To this end, we employ (time-dependent) density functional theory in conjunction with the polarizable-continuum model. We find that the torsion between adjacent monomer units plays a key role, as it strongly influences the electronic structure of the molecule, including energy gap, ionization potential, and band widths. Alkylization promotes delocalization of the molecular orbitals up to the first methyl unit, regardless of the chain length, leading to an overall shift of the energy levels. The alterations in the electronic structure are reflected in the optical absorption, which is additionally affected by dynamical solute-solvent interactions. Taking all these effects into account, solvents decrease the optical gap by an amount that depends on its polarity, and concomitantly increase the oscillator strength of the first excitation. The interaction with a dopant molecule promotes planarization. In such scenario, solvation and alkylization enhance charge transfer both in the ground state and in the excited state.
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Affiliation(s)
- Jannis Krumland
- Humboldt-Universität zu Berlin, Physics Department and IRIS Adlershof, 12489 Berlin, Germany.
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19
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Tripp MW, Bischof D, Dreher M, Witte G, Koert U. Synthesis and Molecular Properties of Partially Fluorinated DNTTs**. European J Org Chem 2021. [DOI: 10.1002/ejoc.202001635] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Matthias W. Tripp
- Department of Chemistry Philipps-Universität Marburg Hans-Meerwein-Straße 4 35032 Marburg Germany
| | - Daniel Bischof
- Department of Physics Philipps-Universität Marburg Renthof 7 35032 Marburg Germany
| | - Maximilian Dreher
- Department of Physics Philipps-Universität Marburg Renthof 7 35032 Marburg Germany
| | - Gregor Witte
- Department of Physics Philipps-Universität Marburg Renthof 7 35032 Marburg Germany
| | - Ulrich Koert
- Department of Chemistry Philipps-Universität Marburg Hans-Meerwein-Straße 4 35032 Marburg Germany
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20
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Palummo M, Raimondo L, Hogan C, Goletti C, Trabattoni S, Sassella A. Nature of Optical Excitations in Porphyrin Crystals: A Joint Experimental and Theoretical Study. J Phys Chem Lett 2021; 12:869-875. [PMID: 33428409 PMCID: PMC8023704 DOI: 10.1021/acs.jpclett.0c03581] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 01/07/2021] [Indexed: 06/12/2023]
Abstract
The nature of optical excitations and the spatial extent of excitons in organic semiconductors, both of which determine exciton diffusion and carrier mobilities, are key factors for the proper understanding and tuning of material performances. Using a combined experimental and theoretical approach, we investigate the excitonic properties of meso-tetraphenyl porphyrin-Zn(II) crystals. We find that several bands contribute to the optical absorption spectra, beyond the four main ones considered here as the analogue to the four frontier molecular orbitals of the Gouterman model commonly adopted for the isolated molecule. By using many-body perturbation theory in the GW and Bethe-Salpeter equation approach, we interpret the experimental large optical anisotropy as being due to the interplay between long- and short-range intermolecular interactions. In addition, both localized and delocalized excitons in the π-stacking direction are demonstrated to determine the optical response, in agreement with recent experimental observations reported for organic crystals with similar molecular packing.
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Affiliation(s)
- Maurizia Palummo
- INFN,
Dipartimento di Fisica, Università
di Roma Tor Vergata, Via della Ricerca Scientifica 1, I-00133 Roma, Italy
| | - Luisa Raimondo
- Dipartimento
di Scienza dei Materiali, Università
degli Studi di Milano-Bicocca, Via Roberto Cozzi 55, I-20125 Milano, Italy
| | - Conor Hogan
- Istituto
di Struttura della Materia-CNR (ISM-CNR), Via del Fosso del Cavaliere 100, I-00133 Roma, Italy
- Dipartimento
di Fisica, Università di Roma Tor
Vergata, Via della Ricerca
Scientifica 1, I-00133 Roma, Italy
| | - Claudio Goletti
- Dipartimento
di Fisica, Università di Roma Tor
Vergata, Via della Ricerca
Scientifica 1, I-00133 Roma, Italy
| | - Silvia Trabattoni
- Dipartimento
di Scienza dei Materiali, Università
degli Studi di Milano-Bicocca, Via Roberto Cozzi 55, I-20125 Milano, Italy
| | - Adele Sassella
- Dipartimento
di Scienza dei Materiali, Università
degli Studi di Milano-Bicocca, Via Roberto Cozzi 55, I-20125 Milano, Italy
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21
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Van Schenck JDB, Mayonado G, Anthony JE, Graham MW, Ostroverkhova O. Molecular packing-dependent exciton dynamics in functionalized anthradithiophene derivatives: From solutions to crystals. J Chem Phys 2020; 153:164715. [PMID: 33138416 DOI: 10.1063/5.0026072] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Understanding the impact of inter-molecular orientation on the optical properties of organic semiconductors is important for designing next-generation organic (opto)electronic and photonic devices. However, fundamental aspects of how various features of molecular packing in crystalline systems determine the nature and dynamics of excitons have been a subject of debate. Toward this end, we present a systematic study of how various molecular crystal packing motifs affect the optical properties of a class of high-performance organic semiconductors: functionalized derivatives of fluorinated anthradithiophene. The absorptive and emissive species present in three such derivatives (exhibiting "brickwork," "twisted-columnar," and "sandwich-herringbone" motifs, controlled by the side group R) were analyzed both in solution and in single crystals, using various modalities of optical and photoluminescence spectroscopy, revealing the nature of these excited states. In solution, in the emission band, two states were identified: a Franck-Condon state present at all concentrations and an excimer that emerged at higher concentrations. In single crystal systems, together with ab initio calculations, it was found in the absorptive band that Frenkel and Charge Transfer (CT) excitons mixed due to nonvanishing CT integrals in all derivatives, but the amount of admixture and exciton delocalization depended on the packing, with the "sandwich-herringbone" packing motif least conducive to delocalization. Three emissive species in the crystal phase were also identified: Frenkel excitons, entangled triplet pairs 1(TT) (which are precursors to forming free triplet states via singlet fission), and self-trapped excitons (STEs, similar in origin to excimers present in concentrated solution). The "twisted-columnar" packing motif was most conducive to the formation of Frenkel excitons delocalized over 4-7 molecules depending on the temperature. These delocalized Frenkel states were dominant across the full temperature range (78 K-293 K), though at lower temperatures, the entangled triplet states and STEs were present. In the derivative with the "brickwork" packing, all three emissive species were observed across the full temperature range and, most notably, the 1(TT) state was present at room temperature. Finally, the derivative with the "sandwich-herringbone" packing exhibited localized Frenkel excitons and had a strong propensity for self-trapped exciton formation even at higher temperatures. In this derivative, no formation of the 1(TT) state was observed. The temperature-dependent dynamics of these emissive states are reported, as well as their origin in fundamental inter-molecular interactions.
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Affiliation(s)
- J D B Van Schenck
- Department of Physics, Oregon State University, Corvallis, Oregon 97330, USA
| | - G Mayonado
- Department of Physics, Oregon State University, Corvallis, Oregon 97330, USA
| | - J E Anthony
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, USA
| | - M W Graham
- Department of Physics, Oregon State University, Corvallis, Oregon 97330, USA
| | - O Ostroverkhova
- Department of Physics, Oregon State University, Corvallis, Oregon 97330, USA
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22
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Wang Q, Chen MT, Franco-Cañellas A, Shen B, Geiger T, F. Bettinger H, Schreiber F, Salzmann I, Gerlach A, Duhm S. Impact of fluorination on interface energetics and growth of pentacene on Ag(111). BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2020; 11:1361-1370. [PMID: 32974114 PMCID: PMC7492695 DOI: 10.3762/bjnano.11.120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 08/19/2020] [Indexed: 05/26/2023]
Abstract
We studied the structural and electronic properties of 2,3,9,10-tetrafluoropentacene (F4PEN) on Ag(111) via X-ray standing waves (XSW), low-energy electron diffraction (LEED) as well as ultraviolet and X-ray photoelectron spectroscopy (UPS and XPS). XSW revealed that the adsorption distances of F4PEN in (sub)monolayers on Ag(111) were 3.00 Å for carbon atoms and 3.05 Å for fluorine atoms. The F4PEN monolayer was essentially lying on Ag(111), and multilayers adopted π-stacking. Our study shed light not only on the F4PEN-Ag(111) interface but also on the fundamental adsorption behavior of fluorinated pentacene derivatives on metals in the context of interface energetics and growth mode.
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Affiliation(s)
- Qi Wang
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Meng-Ting Chen
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123, People’s Republic of China
| | - Antoni Franco-Cañellas
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Bin Shen
- Institut für Organische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Thomas Geiger
- Institut für Organische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Holger F. Bettinger
- Institut für Organische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Frank Schreiber
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Ingo Salzmann
- Department of Physics, Department of Chemistry & Biochemistry, Concordia University, 7141 Sherbrooke St. West, Montreal, Quebec H4B 1R6, Canada
| | - Alexander Gerlach
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Steffen Duhm
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123, People’s Republic of China
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23
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Franco-Cañellas A, Duhm S, Gerlach A, Schreiber F. Binding and electronic level alignment of π-conjugated systems on metals. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2020; 83:066501. [PMID: 32101802 DOI: 10.1088/1361-6633/ab7a42] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
We review the binding and energy level alignment of π-conjugated systems on metals, a field which during the last two decades has seen tremendous progress both in terms of experimental characterization as well as in the depth of theoretical understanding. Precise measurements of vertical adsorption distances and the electronic structure together with ab initio calculations have shown that most of the molecular systems have to be considered as intermediate cases between weak physisorption and strong chemisorption. In this regime, the subtle interplay of different effects such as covalent bonding, charge transfer, electrostatic and van der Waals interactions yields a complex situation with different adsorption mechanisms. In order to establish a better understanding of the binding and the electronic level alignment of π-conjugated molecules on metals, we provide an up-to-date overview of the literature, explain the fundamental concepts as well as the experimental techniques and discuss typical case studies. Thereby, we relate the geometric with the electronic structure in a consistent picture and cover the entire range from weak to strong coupling.
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Affiliation(s)
- Antoni Franco-Cañellas
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
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24
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Valencia AM, Guerrini M, Cocchi C. Ab initio modelling of local interfaces in doped organic semiconductors. Phys Chem Chem Phys 2020; 22:3527-3538. [PMID: 31994551 DOI: 10.1039/c9cp06655a] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Doping in organic semiconductors remains a debated issue from both an experimental and ab initio perspective. Due to the complexity of these systems, which exhibit a low degree of crystallinity and high level of disorder, modelling doped organic semiconductors from first-principles calculations is not a trivial task, as their electronic and optical properties are sensitive to the choice of initial geometries. A crucial aspect to take into account, in view of rationalizing the electronic structure of these materials through ab initio calculations, is the role of local donor/acceptor interfaces. We address this problem in the framework of state-of-the-art density-functional theory and many-body perturbation theory, investigating the structural, electronic, and optical properties of quaterthiophene and sexithiophene oligomers doped by 2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-quinodimethane (F4TCNQ). We consider different model structures ranging from isolated dimers and trimers, to periodic stacks. Our results demonstrate that the choice of the initial geometry critically impacts the resulting electronic structure and the degree of charge transfer in the materials, depending on the amount and on the nature of the local interfaces between donor and acceptor species. The optical spectra appear less sensitive to these parameters at least from a first glance, although a quantitative analysis of the excitations reveals that their Frenkel or charge-transfer character is affected by the characteristics of the donor/acceptor interfaces as well as by the donor length. Our findings represent an important step forward towards an insightful first-principles description of the microscopic properties of doped organic semiconductors complementary to experiments.
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Affiliation(s)
- Ana M Valencia
- Humboldt-Universität zu Berlin, Physics Department and IRIS Adlershof, Zum Großen Windkanal 6, 12489 Berlin, Germany.
| | - Michele Guerrini
- Humboldt-Universität zu Berlin, Physics Department and IRIS Adlershof, Zum Großen Windkanal 6, 12489 Berlin, Germany.
| | - Caterina Cocchi
- Humboldt-Universität zu Berlin, Physics Department and IRIS Adlershof, Zum Großen Windkanal 6, 12489 Berlin, Germany.
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25
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Affiliation(s)
- Timothy W. Schmidt
- ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, NSW 2052, Australia
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26
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Golze D, Dvorak M, Rinke P. The GW Compendium: A Practical Guide to Theoretical Photoemission Spectroscopy. Front Chem 2019; 7:377. [PMID: 31355177 PMCID: PMC6633269 DOI: 10.3389/fchem.2019.00377] [Citation(s) in RCA: 153] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 05/08/2019] [Indexed: 12/22/2022] Open
Abstract
The GW approximation in electronic structure theory has become a widespread tool for predicting electronic excitations in chemical compounds and materials. In the realm of theoretical spectroscopy, the GW method provides access to charged excitations as measured in direct or inverse photoemission spectroscopy. The number of GW calculations in the past two decades has exploded with increased computing power and modern codes. The success of GW can be attributed to many factors: favorable scaling with respect to system size, a formal interpretation for charged excitation energies, the importance of dynamical screening in real systems, and its practical combination with other theories. In this review, we provide an overview of these formal and practical considerations. We expand, in detail, on the choices presented to the scientist performing GW calculations for the first time. We also give an introduction to the many-body theory behind GW, a review of modern applications like molecules and surfaces, and a perspective on methods which go beyond conventional GW calculations. This review addresses chemists, physicists and material scientists with an interest in theoretical spectroscopy. It is intended for newcomers to GW calculations but can also serve as an alternative perspective for experts and an up-to-date source of computational techniques.
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Affiliation(s)
- Dorothea Golze
- Department of Applied Physics, Aalto University, School of Science, Espoo, Finland
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27
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Guerrini M, Cocchi C, Calzolari A, Varsano D, Corni S. Interplay between Intra- and Intermolecular Charge Transfer in the Optical Excitations of J-Aggregates. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2019; 123:6831-6838. [PMID: 30949274 PMCID: PMC6443228 DOI: 10.1021/acs.jpcc.8b11709] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 02/13/2019] [Indexed: 05/17/2023]
Abstract
In a first-principles study based on density functional theory and many-body perturbation theory, we address the interplay between intra- and intermolecular interactions in a J-aggregate formed by push-pull organic dyes by investigating its electronic and optical properties. We find that the most intense excitation dominating the spectral onset of the aggregate, i.e., the J-band, exhibits a combination of intramolecular charge transfer, coming from the push-pull character of the constituting dyes, and intermolecular charge transfer, due to the dense molecular packing. We also show the presence of a pure intermolecular charge-transfer excitation within the J-band, which is expected to play a relevant role in the emission properties of the J-aggregate. Our results shed light on the microscopic character of optical excitations of J-aggregates and offer new perspectives to further understand the nature of collective excitations in organic semiconductors.
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Affiliation(s)
- Michele Guerrini
- Dipartimento
FIM, Università di Modena e Reggio
Emilia, 41125 Modena, Italy
- CNR
Nano Istituto Nanoscienze, Centro S3, 41125 Modena, Italy
- Department
of Physics and IRIS Adlershof, Humboldt-Universität
zu Berlin, 12489 Berlin, Germany
| | - Caterina Cocchi
- Department
of Physics and IRIS Adlershof, Humboldt-Universität
zu Berlin, 12489 Berlin, Germany
- E-mail: (C.C.)
| | | | - Daniele Varsano
- CNR
Nano Istituto Nanoscienze, Centro S3, 41125 Modena, Italy
- E-mail: (D.V.)
| | - Stefano Corni
- CNR
Nano Istituto Nanoscienze, Centro S3, 41125 Modena, Italy
- Dipartimento
di Scienze Chimiche, Università di
Padova, 35131 Padova, Italy
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