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Zheng Y, Rojas-Gatjens E, Lee M, Reichmanis E, Silva-Acuña C. Unveiling Multiquantum Excitonic Correlations in Push-Pull Polymer Semiconductors. J Phys Chem Lett 2024; 15:3705-3712. [PMID: 38546242 PMCID: PMC11017317 DOI: 10.1021/acs.jpclett.4c00065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 03/19/2024] [Accepted: 03/21/2024] [Indexed: 04/12/2024]
Abstract
Bound and unbound Frenkel-exciton pairs are essential transient precursors for a variety of photophysical and biochemical processes. In this work, we identify bound and unbound Frenkel-exciton complexes in an electron push-pull polymer semiconductor using coherent two-dimensional spectroscopy. We find that the dominant A0-1 peak of the absorption vibronic progression is accompanied by a subpeak, each dressed by distinct vibrational modes. By considering the Liouville pathways within a two-exciton model, the imbalanced cross-peaks in one-quantum rephasing and nonrephasing spectra can be accounted for by the presence of pure biexcitons. The two-quantum nonrephasing spectra provide direct evidence for unbound exciton pairs and biexcitons with dominantly attractive force. In addition, the spectral features of unbound exciton pairs show mixed absorptive and dispersive character, implying many-body interactions within the correlated Frenkel-exciton pairs. Our work offers novel perspectives on the Frenkel-exciton complexes in semiconductor polymers.
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Affiliation(s)
- Yulong Zheng
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, 901 Atlantic Drive, Atlanta, Georgia 30332, United States
| | - Esteban Rojas-Gatjens
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, 901 Atlantic Drive, Atlanta, Georgia 30332, United States
| | - Myeongyeon Lee
- Department
of Chemical & Biomolecular Engineering, Lehigh University, 124 E. Morton Street, Bethlehem, Pennsylvania 18015, United States
| | - Elsa Reichmanis
- Department
of Chemical & Biomolecular Engineering, Lehigh University, 124 E. Morton Street, Bethlehem, Pennsylvania 18015, United States
| | - Carlos Silva-Acuña
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, 901 Atlantic Drive, Atlanta, Georgia 30332, United States
- Institut
Courtois & Département de physique, Université de Montréal, 1375 Avenue Thérèse-Lavoie-Roux, Montréal, Québec H2V 0B3, Canada
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2
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Zheng Y, Venkatesh R, Rojas-Gatjens E, Reichmanis E, Silva-Acuña C. Exciton Bimolecular Annihilation Dynamics in Push-Pull Semiconductor Polymers. J Phys Chem Lett 2024; 15:272-280. [PMID: 38166236 PMCID: PMC10788955 DOI: 10.1021/acs.jpclett.3c03094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 12/17/2023] [Accepted: 12/28/2023] [Indexed: 01/04/2024]
Abstract
Exciton-exciton annihilation is a ubiquitous nonlinear dynamic phenomenon in materials hosting Frenkel excitons. In this work, we investigate the nonlinear exciton dynamics of an electron push-pull conjugated polymer by fluence-dependent transient absorption and excitation-correlation photoluminescence spectroscopy, where we can quantitatively show the latter to be a more selective probe of the nonlinear dynamics. Simulations based on a time-independent exciton annihilation model show a decreasing trend for the extracted annihilation rates with excitation fluence. Further investigation of the fluence-dependent transients suggests that the exciton-exciton annihilation bimolecular rates are not constant in time, displaying a t-1/2 time dependence, which we rationalize as reflective of one-dimensional exciton diffusion, with a diffusion length estimated to be 9 ± 2 nm. In addition, exciton annihilation gives rise to a long-lived species that recombines on a nanosecond time scale. Our conclusions shed broad light onto nonlinear exciton dynamics in push-pull conjugated polymers.
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Affiliation(s)
- Yulong Zheng
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, 901 Atlantic Drive, Atlanta, Georgia 30332, United States
| | - Rahul Venkatesh
- School
of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive NW, Atlanta, Georgia 30332, United States
| | - Esteban Rojas-Gatjens
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, 901 Atlantic Drive, Atlanta, Georgia 30332, United States
| | - Elsa Reichmanis
- Department
of Chemical & Biomolecular Engineering, Lehigh University, 124 E. Morton Street, Bethlehem, Pennsylvania 18015, United States
| | - Carlos Silva-Acuña
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, 901 Atlantic Drive, Atlanta, Georgia 30332, United States
- Institut
Courtois & Département de physique, Université de Montréal, 1375 Avenue Thérèse-Lavoie-Roux, Montréal H2V 0B3, Québec, Canada
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3
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Rojas-Gatjens E, Li H, Vega-Flick A, Cortecchia D, Petrozza A, Bittner ER, Srimath Kandada AR, Silva-Acuña C. Many-Exciton Quantum Dynamics in a Ruddlesden-Popper Tin Iodide. J Phys Chem C Nanomater Interfaces 2023; 127:21194-21203. [PMID: 37937156 PMCID: PMC10626601 DOI: 10.1021/acs.jpcc.3c04896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 10/01/2023] [Indexed: 11/09/2023]
Abstract
We present a study on the many-body exciton interactions in a Ruddlesden-Popper tin halide, namely, (PEA)2SnI4 (PEA = phenylethylammonium), using coherent two-dimensional electronic spectroscopy. The optical dephasing times of the third-order polarization observed in these systems are determined by exciton many-body interactions and lattice fluctuations. We investigate the excitation-induced dephasing (EID) and observe a significant reduction of the dephasing time with increasing excitation density as compared to its lead counterpart (PEA)2PbI4, which we have previously reported in a separate publication [J. Chem. Phys.2020, 153, 164706]. Surprisingly, we find that the EID interaction parameter is four orders of magnitude higher in (PEA)2SnI4 than that in (PEA)2PbI4. This increase in the EID rate may be due to exciton localization arising from a more statically disordered lattice in the tin derivative. This is supported by the observation of multiple closely spaced exciton states and the broadening of the linewidth with increasing population time (spectral diffusion), which suggests a static disordered structure relative to the highly dynamic lead-halide. Additionally, we find that the exciton nonlinear coherent lineshape shows evidence of a biexcitonic state with low binding energy (<10 meV) not observed in the lead system. We model the lineshapes based on a stochastic scattering theory that accounts for the interaction with a nonstationary population of dark background excitations. Our study provides evidence of differences in the exciton quantum dynamics between tin- and lead-based Ruddlesden-Popper metal halides (RPMHs) and links them to the exciton-exciton interaction strength and the static disorder aspect of the crystalline structure.
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Affiliation(s)
- Esteban Rojas-Gatjens
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia, 30332, United States
- School
of Physics, Georgia Institute of Technology, Atlanta, Georgia, 30332, United
States
| | - Hao Li
- Department
of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Alejandro Vega-Flick
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia, 30332, United States
| | - Daniele Cortecchia
- Center
for Nano Science and Technology@PoliMi, Istituto Italiano di Tecnologia, Milan 20133, Italy
| | - Annamaria Petrozza
- Center
for Nano Science and Technology@PoliMi, Istituto Italiano di Tecnologia, Milan 20133, Italy
| | - Eric R. Bittner
- Department
of Chemistry, University of Houston, Houston, Texas 77204, United States
- Center
for Nonlinear Studies, Los Alamos National
Laboratory, Los Alamos, New Mexico 87544, United States
| | - Ajay Ram Srimath Kandada
- Department
of Physics, Wake Forest University, Winston–Salem, North
Carolina 27587, United States
- Center
for Functional Materials, Wake Forest University, Winston–Salem, North
Carolina 27109, United States
| | - Carlos Silva-Acuña
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia, 30332, United States
- School
of Physics, Georgia Institute of Technology, Atlanta, Georgia, 30332, United
States
- School
of Materials Science and Engineering, Georgia
Institute of Technology, Atlanta, Georgia, 30332, United States
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Moretti L, Rojas-Gatjens E, Uboldi L, Tiede DO, Kumar EJ, Trovatello C, Preda F, Perri A, Manzoni C, Cerullo G, Srimath Kandada AR. Measurement principles for quantum spectroscopy of molecular materials with entangled photons. J Chem Phys 2023; 159:084201. [PMID: 37615395 DOI: 10.1063/5.0156598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 08/01/2023] [Indexed: 08/25/2023] Open
Abstract
Nonlinear spectroscopy with quantum entangled photons is an emerging field of research that holds the promise to achieve superior signal-to-noise ratio and effectively isolate many-body interactions. Photon sources used for this purpose, however, lack the frequency tunability and spectral bandwidth demanded by contemporary molecular materials. Here, we present design strategies for efficient spontaneous parametric downconversion to generate biphoton states with adequate spectral bandwidth and at visible wavelengths. Importantly, we demonstrate, by suitable design of the nonlinear optical interaction, the scope to engineer the degree of spectral correlations between the photons of the pair. We also present an experimental methodology to effectively characterize such spectral correlations. Importantly, we believe that such a characterization tool can be effectively adapted as a spectroscopy platform to optically probe system-bath interactions in materials.
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Affiliation(s)
- Luca Moretti
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milano, Italy
- Department of Physics and Center for Functional Materials, Wake Forest University, 1834 Wake Forest Road, Winston-Salem, North Carolina 27109, USA
| | - Esteban Rojas-Gatjens
- Department of Physics and Center for Functional Materials, Wake Forest University, 1834 Wake Forest Road, Winston-Salem, North Carolina 27109, USA
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Lorenzo Uboldi
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milano, Italy
- Department of Physics and Center for Functional Materials, Wake Forest University, 1834 Wake Forest Road, Winston-Salem, North Carolina 27109, USA
| | - David Otto Tiede
- Department of Physics and Center for Functional Materials, Wake Forest University, 1834 Wake Forest Road, Winston-Salem, North Carolina 27109, USA
- Institute of Materials Science of Sevilla, Spanish National Research Council, Américo Vespucio, 49, 41092 Sevilla, Spain
| | - Evan J Kumar
- Department of Physics and Center for Functional Materials, Wake Forest University, 1834 Wake Forest Road, Winston-Salem, North Carolina 27109, USA
| | - Chiara Trovatello
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milano, Italy
- Department of Mechanical Engineering, Columbia University, New York, New York 10027, USA
| | | | - Antonio Perri
- NIREOS S.R.L., Via G. Durando 39, 20158 Milano, Italy
| | - Cristian Manzoni
- IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milano, Italy
| | - Giulio Cerullo
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milano, Italy
- IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milano, Italy
| | - Ajay Ram Srimath Kandada
- Department of Physics and Center for Functional Materials, Wake Forest University, 1834 Wake Forest Road, Winston-Salem, North Carolina 27109, USA
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Rojas-Gatjens E, Yallum KM, Shi Y, Zheng Y, Bills T, Perini CAR, Correa-Baena JP, Ginger DS, Banerji N, Silva-Acuña C. Resolving Nonlinear Recombination Dynamics in Semiconductors via Ultrafast Excitation Correlation Spectroscopy: Photoluminescence versus Photocurrent Detection. J Phys Chem C Nanomater Interfaces 2023; 127:15969-15977. [PMID: 37609378 PMCID: PMC10440815 DOI: 10.1021/acs.jpcc.3c04755] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Indexed: 08/24/2023]
Abstract
We explore the application of excitation correlation spectroscopy to detect nonlinear photophysical dynamics in two distinct semiconductor classes through time-integrated photoluminescence and photocurrent measurements. In this experiment, two variably delayed femtosecond pulses excite the semiconductor, and the time-integrated photoluminescence or photocurrent component arising from the nonlinear dynamics of the populations induced by each pulse is measured as a function of inter-pulse delay by phase-sensitive detection with a lock-in amplifier. We focus on two limiting materials systems with contrasting optical properties: a prototypical lead-halide perovskite (LHP) solar cell, in which primary photoexcitations are charge photocarriers, and a single-component organic-semiconductor diode, which features Frenkel excitons as primary photoexcitations. The photoexcitation dynamics perceived by the two detection schemes in these contrasting systems are distinct. Nonlinear-dynamic contributions in the photoluminescence detection scheme arise from contributions to radiative recombination in both materials systems, while photocurrent arises directly in the LHP but indirectly following exciton dissociation in the organic system. Consequently, the basic photophysics of the two systems are reflected differently when comparing measurements with the two detection schemes. Our results indicate that photoluminescence detection in the LHP system provides valuable information about trap-assisted and Auger recombination processes, but that these processes are convoluted in a nontrivial way in the photocurrent response and are therefore difficult to differentiate. In contrast, the organic-semiconductor system exhibits more directly correlated responses in the nonlinear photoluminescence and photocurrent measurements, as charge carriers are secondary excitations only generated through exciton dissociation processes. We propose that bimolecular annihilation pathways mainly contribute to the generation of charge carriers in single-component organic semiconductor devices. Overall, our work highlights the utility of excitation correlation spectroscopy in modern semiconductor materials research, particularly in the analysis of nonlinear photophysical processes, which are deterministic for their electronic and optical properties.
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Affiliation(s)
- Esteban Rojas-Gatjens
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332, United States
| | - Kaila M. Yallum
- Department
of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, Bern CH-3012, Switzerland
| | - Yangwei Shi
- Department
of Chemistry, University of Washington, Seattle, Washington 98195, United States
- Molecular
Engineering & Sciences Institute, University
of Washington, Seattle, Washington 98195, United States
| | - Yulong Zheng
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332, United States
| | - Tyler Bills
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332, United States
| | - Carlo A. R. Perini
- School
of Materials Science and Engineering, Georgia
Institute of Technology, Atlanta, Georgia 30332, United States
| | - Juan-Pablo Correa-Baena
- School
of Materials Science and Engineering, Georgia
Institute of Technology, Atlanta, Georgia 30332, United States
| | - David S. Ginger
- Department
of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Natalie Banerji
- Department
of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, Bern CH-3012, Switzerland
| | - Carlos Silva-Acuña
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332, United States
- School
of Materials Science and Engineering, Georgia
Institute of Technology, Atlanta, Georgia 30332, United States
- School of
Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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6
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Perini CAR, Rojas-Gatjens E, Ravello M, Castro-Mendez AF, Hidalgo J, An Y, Kim S, Lai B, Li R, Silva-Acuña C, Correa-Baena JP. Interface Reconstruction from Ruddlesden-Popper Structures Impacts Stability in Lead Halide Perovskite Solar Cells. Adv Mater 2022; 34:e2204726. [PMID: 36245328 DOI: 10.1002/adma.202204726] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 09/24/2022] [Indexed: 06/16/2023]
Abstract
The impact of the bulky-cation-modified interfaces on halide perovskite solar cell stability is underexplored. In this work, the thermal instability of the bulky-cation interface layers used in the state-of-the-art solar cells is demonstrated. X-ray photoelectron spectroscopy and synchrotron-based grazing-incidence X-ray scattering measurements reveal significant changes in the chemical composition and structure at the surface of these films that occur under thermal stress. The changes impact charge-carrier dynamics and device operation, as shown in transient photoluminescence, excitation correlation spectroscopy, and solar cells. The type of cation used for surface treatment affects the extent of these changes, where long carbon chains provide more stable interfaces. These results highlight that prolonged annealing of the treated interfaces is critical to enable reliable reporting of performances and to drive the selection of different bulky cations.
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Affiliation(s)
| | - Esteban Rojas-Gatjens
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Magdalena Ravello
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | | | - Juanita Hidalgo
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Yu An
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Sanggyun Kim
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Barry Lai
- Advanced Photon Source, Argonne National Laboratory, 9700 Cass Avenue, Lemont, IL, 60439, USA
| | - Ruipeng Li
- National Synchrotron Light Source II (NSLS-II), Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Carlos Silva-Acuña
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332, USA
- School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Juan-Pablo Correa-Baena
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
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7
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Rojas-Gatjens E, Silva-Acuña C, Kandada ARS. Peculiar anharmonicity of Ruddlesden Popper metal halides: temperature-dependent phonon dephasing. Mater Horiz 2022; 9:492-499. [PMID: 34904992 DOI: 10.1039/d1mh01010g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The anharmonicity of the Ruddlesden Popper metal-halide lattice, and its consequences for their electronic and optical properties, are paramount in their basic semiconductor physics. It is thus critical to identify specific anharmonic optical phonons that govern their photophysics. Here, we address the nature of phonon-phonon scattering probabilities of the resonantly excited optical phonons that dress the electronic transitions in these materials. Based on the temperature dependence of the coherent phonon lifetimes, we isolate the dominant anharmonic phonon and quantify its phonon-phonon interaction strength. Intriguingly, we also observe that the anharmonicity is distinct for different phonons, with a few select modes exhibiting temperature-independent coherence lifetimes, indicating their predominantly harmonic nature. However, the population and dephasing dynamics of excitons are dominated by the anharmonic phonon.
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Affiliation(s)
- Esteban Rojas-Gatjens
- School of Chemistry and Biochemistry, Georgia Institute of Technology, 901 Atlantic Drive, Atlanta, Georgia 30332, USA.
| | - Carlos Silva-Acuña
- School of Chemistry and Biochemistry, Georgia Institute of Technology, 901 Atlantic Drive, Atlanta, Georgia 30332, USA.
- School of Physics, Georgia Institute of Technology, 837 State Street, Atlanta, Georgia 30332, USA
- School of Materials Science and Engineering, Georgia Institute of Technology, North Avenue, Atlanta, GA 30332, USA
| | - Ajay Ram Srimath Kandada
- Department of Physics and Center for Functional Materials, Wake Forest University, 1834 Wake Forest Road, Winston-Salem, NC 27109, USA.
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