A molecular movie of ultrafast singlet fission

Nature Communications, Год журнала: 2019, Номер 10(1)

Опубликована: Сен. 16, 2019

Abstract The complex dynamics of ultrafast photoinduced reactions are governed by their evolution along vibronically coupled potential energy surfaces. It is now often possible to identify such processes, but a detailed depiction the crucial nuclear degrees freedom involved typically remains elusive. Here, combining excited-state time-domain Raman spectroscopy and tree-tensor network state simulations, we construct full 108-atom molecular movie singlet fission in pentacene dimer, explicitly treating 252 vibrational modes on 5 electronic states. We assign tuning coupling modes, quantifying relative intensities contributions, demonstrate how these coherently synchronise drive reaction. Our combined experimental theoretical approach reveals atomic-scale mechanism can be generalized other systems. This will enable mechanistic insight structural level, with ultimate aim rationally design molecules maximise efficiency reactions.

Язык: Английский

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Fluorescence-Based Sensing of Pesticides Using Supramolecular Chemistry

Frontiers in Chemistry, Год журнала: 2021, Номер 9

Опубликована: Апрель 16, 2021

The detection of pesticides in real-world environments is a high priority for broad range applications, including areas public health, environmental remediation, and agricultural sustainability. While many methods pesticide currently exist, the use supramolecular fluorescence-based has significant practical advantages. Herein, we will review methods, with particular focus on chemistry-based methods. Illustrative examples that show how such have achieved success are also included, as highlighted future research development.

Язык: Английский

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Marcus inverted region of charge transfer from low-dimensional semiconductor materials

Nature Communications, Год журнала: 2021, Номер 12(1)

Опубликована: Ноя. 3, 2021

A key process underlying the application of low-dimensional, quantum-confined semiconductors in energy conversion is charge transfer from these materials, which, however, has not been fully understood yet. Extensive studies colloidal quantum dots reported rates increasing monotonically with driving forces, never displaying an inverted region predicted by Marcus theory. The likely bypassed Auger-like whereby excessive force used to excite another Coulomb-coupled charge. Herein, instead measuring excitonic states (coupled electron-hole pairs), we build a unique model system using zero-dimensional or two-dimensional nanoplatelets and surface-adsorbed molecules that allows for transiently-populated, single-charge states. clearly revealed systems. Thus, follows Auger-assisted conventional models, respectively. This knowledge should enable rational design energetics efficient extraction low-dimensional semiconductor materials as well suppression associated energy-wasting recombination.

Язык: Английский

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Influence of Vibronic Coupling on Ultrafast Singlet Fission in a Linear Terrylenediimide Dimer

Journal of the American Chemical Society, Год журнала: 2021, Номер 143(4), С. 2049 - 2058

Опубликована: Янв. 19, 2021

Singlet fission (SF) is a photophysical process capable of boosting the efficiency solar cells. Recent experimental investigations into mechanism SF provide evidence for coherent mixing between singlet, triplet, and charge transfer basis states. Up until now, this interpretation has largely focused on electronic interactions; however, nuclear motions resulting in vibronic coupling have been suggested to support rapid efficient organic chromophore assemblies. Further information about complex interactions excited states needed understand potential role SF. Here, we report mixed singlet correlated triplet pair giving rise sub-50 fs terrylene-3,4:11,12-bis(dicarboximide) (TDI) dimer which two TDI molecules are covalently linked by direct N–N connection at one their imide positions, leading linear with perpendicular π systems. We observe low-frequency wavepackets initial predominantly product triplet-dominated This implies non-negligible dependence nonadiabatic dimer. interpret our results framework modified Holstein Hamiltonian, predicts that modes high-frequency lead pure These highlight how can shape energy landscape underlying ultrafast

Язык: Английский

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π-Stacking-Dependent Vibronic Couplings Drive Excited-State Dynamics in Perylenediimide Assemblies

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(25), С. 11386 - 11396

Опубликована: Июнь 14, 2022

Vibronic coupling, the interplay of electronic and nuclear vibrational motion, is considered a critical mechanism in photoinduced reactions such as energy transfer, charge singlet fission. However, our understanding how particular vibronic couplings impact excited-state dynamics lacking due to limited number experimental studies model molecular systems. Herein, we use two-dimensional spectroscopy (2DES) launch interrogate range coherences two distinct types perylenediimide slip stacks─along short long axes, which form either an excimer or mixed state between Frenkel exciton (FE) transfer states. We explore functionality these using quantum beatmaps, display Fourier amplitude signal oscillations function pump probe frequencies, along with knowledge characteristic signatures FE, ionic, species. find that low-frequency mode short-axis stack appears concomitantly formation state, survives 2-fold longer than FE reference monomer, shows phase shift compared other modes. For long-axis stacks, pair modes coupled high-frequency coordinate were found play role mixed-state generation. Our findings thus experimentally reveal complex varying roles tightly packed multimers undergoing processes.

Язык: Английский

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Advances in Molecular Design and Photophysical Engineering of Perylene Bisimide-Containing Polyads and Multichromophores for Film-Based Fluorescent Sensors

The Journal of Physical Chemistry B, Год журнала: 2023, Номер 127(4), С. 828 - 837

Опубликована: Янв. 24, 2023

Film-based fluorescent sensors (FFSs) represent an important chemistry technology for meeting the urgent needs of on-site and real-time analysis, thereby enabling significant applications in environmental health monitoring. As core FFSs, innovative design sensing fluorophores their intrinsic excited-state-related response nature endow FFSs with superior performances endless expansion. In this Perspective, we specifically focus on perylene bisimide (PBI)-containing polyads multichromophores rigid configuration notable photochemical stability developing high-performance FFSs. These nonplanar structures mitigate aggregation create abundant gaps sake mass transfer availability units adlayer films. We also comprehensively discuss how to adjust electronic coupling governing excited-state events by appropriate functionalization strategies, thus providing a plethora valuable insights exploration structure-property relationships these orchestrated molecular systems. Throughout identify opportunities future developments.

Язык: Английский

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Efficient quantum simulation of open quantum system dynamics on noisy quantum computers

Physica Scripta, Год журнала: 2024, Номер 99(3), С. 035101 - 035101

Опубликована: Янв. 8, 2024

Quantum simulation represents the most promising quantum application to demonstrate advantage on near-term noisy intermediate-scale (NISQ) computers, yet available algorithms are prone errors and thus difficult be realized. Herein, we propose a novel scheme utilize intrinsic gate of NISQ devices enable controllable open system dynamics without ancillary qubits or explicit bath engineering, turning unwanted noises into useful resources. Specifically, simulate energy transfer process in photosynthetic dimer IBM-Q cloud. By employing designed decoherence-inducing gates, show that dissipative can simulated efficiently across coherent-to-incoherent regimes with results comparable those numerically-exact classical method. Moreover, calibration routine enables consistent predictive simulations open-quantum intermediate coupling regime. This work provides new direction for era.

Язык: Английский

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Vibronic coherence evolution in multidimensional ultrafast photochemical processes

Nature Communications, Год журнала: 2019, Номер 10(1)

Опубликована: Дек. 9, 2019

Abstract The complex choreography of electronic, vibrational, and vibronic couplings used by photoexcited molecules to transfer energy efficiently is remarkable, but an unambiguous description the temporally evolving states governing these processes has proven experimentally elusive. We use multidimensional electronic-vibrational spectroscopy identify specific time-dependent excited state involving multiple electronic states, high-frequency vibrations, low-frequency vibrations which participate in ultrafast intersystem crossing subsequent relaxation a transition metal complex. discover mechanism driving long-lived charge separation consisting initial electronically-localized vibrational wavepacket triggers delocalization onto two after propagating for ~600 femtoseconds. Electronic consequently occurs through nonadiabatic internal conversion driven 50 cm −1 coupling resulting coherence lasting ~1 picosecond. This study showcases power elucidate complex, non-equilibrium mechanisms molecular coordinates.

Язык: Английский

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Two-Step Charge Separation Passing Through the Partial Charge-Transfer State in a Molecular Dyad

Journal of the American Chemical Society, Год журнала: 2019, Номер 142(3), С. 1564 - 1573

Опубликована: Дек. 23, 2019

Charge separation (CS) in molecular systems usually takes place weakly coupled donor–acceptor dyads where an electron charge moves from the donor to acceptor local excited state of a chromophore. Herein, we present two-step charge-separation process newly synthesized diketopyrrolopyrrole-pyrrolopyrrole (DPP-PP) dyad (AD), which starts initial photoexcited bright exciton and goes through partial charge-transfer (CT) before finally reaching charge-separated state. The evolving CT character is demonstrated complementary use transient absorption, broad-band fluorescence upconversion, impulsive stimulated Raman spectroscopy. relaxes with 1 20 ps during solvent structural fluctuations toluene, respectively, 700 fs for occurring tetrahydrofuran. This evident characteristic excited-state absorption spectra reduced intensity observed on adiabatic potential energy surface. AD THF additionally evolves diabatic surface CS state, whose spectrum converges that DPP anion completely quenched. trend shifting certain vibrational frequencies also supports proposed dynamics mechanism; furthermore, it gives quantitative insight into characters (0.1 e) intermediate (0.5 e), as determined by linear relationship exists between frequency marker modes character. We have found structure bridge enables level electronic communication, can rapidly occur distinct It seems exceptionally strong communication at positions 2 5 pyrrolo[3,2-b]pyrrole core crucial element this mechanism, could be applied organic photovoltaics or light-emitting diodes requiring efficient separation.

Язык: Английский

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Vibronic coherence contributes to photocurrent generation in organic semiconductor heterojunction diodes

Nature Communications, Год журнала: 2020, Номер 11(1)

Опубликована: Янв. 30, 2020

Abstract Charge separation dynamics after the absorption of a photon is fundamental process relevant both for photosynthetic reaction centers and artificial solar conversion devices. It has been proposed that quantum coherence plays role in formation charge carriers organic photovoltaics, but experimental proofs have lacking. Here we report evidence donor/acceptor heterojunctions, form low frequency oscillatory signature kinetics transient nonlinear two-dimensional photocurrent spectroscopy. The decisive initial ~200 femtoseconds as observe distinct signatures coherent generation. This breaks energy barrier limitation formation, thus competing with excitation transfer. physics may inspire design new photovoltaic materials high device performance, which explore effects next-generation optoelectronic applications.

Язык: Английский

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