Interchromophore Rotation-Related Ultrafast Charge Separation at Excited States in Head-to-Tail Linked Perylene Diimide Dyads

Fang, Shaomao; Zhou, Jiadong; Zhou, Xuehong; Jiang, Nianqiang; Liu, Linlin; Xie, Zengqi

doi:10.1021/acs.jpcc.9b03532

Cited by 12 publications

(29 citation statements)

References 28 publications

(50 reference statements)

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“…The molecular rotation has been suggested to be an effective way to trigger the occurrence of SB-CS. 1,46,48 Considering the presence of the triple bond of the linker in these three dimers, molecular torsion may also occur and may facilitate the proceeding of SB-CS. To verify this hypothesis, we performed fs-TA experiment of these three dimers in polystyrene (PS) film in which the two anthracene units were locked, and the molecular rotation was hindered (Fig.…”

Section: Resultsmentioning

confidence: 99%

Linker dependent symmetry breaking charge separation in 9,10-bis(phenylethynyl)anthracene dimers

Liu

Shen

et al. 2022

Mater. Chem. Front.

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Section: Resultsmentioning

confidence: 99%

Linker dependent symmetry breaking charge separation in 9,10-bis(phenylethynyl)anthracene dimers

Liu

Shen

et al. 2022

Mater. Chem. Front.

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“…The time constants of the population of the solvation-stabilized state, SBCT state and charge recombination were determined by global analysis, which yields ∼500 fs, ∼ 2.8 ps and >1 ns (1.2 ns), respectively . To take the fluorescence process of PP into consideration, which competes with the formation of SBCT state, in the long-time window, two processes are independent, the lifetime of fluorescence was fitted to be 1.6 ns by using target model analysis. The much slower charge recombination relative to fast charge separation is consistent with the fact that the recombination lies far into the Marcus inverted region and the orthogonal geometry of two chromophores in PP can render a minimal overlap of the wave functions of electron and hole. , Recently, some studies illustrated that enhanced ISC can be induced via population of the ion-pair state with two proposed mechanisms, radical pair intersystem crossing (RP-ISC) and spin–orbit intersystem crossing (SO-ISC) .…”

Section: Resultsmentioning

confidence: 99%

Distinct Excited-State Dynamics of Near-Orthogonal Perylenimide Dimer: Conformational Planarization versus Symmetry Breaking Charge Transfer

et al. 2019

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Efficient photoinduced charge separation in artificial multichromophoric architectures relies on two critical factors, (i) electronic coupling and (ii) solvation. While the coherent exciton interactions delocalize the excitation energy among molecules, the solvation-dependent dynamical disorder tends to localize it. Local environments such as solvent polarity/dielectric environments exhibit profound effect on mediating the excited-state relaxation dynamics via specific electronic/geometric changes in chromophore multimers. Herein, a comprehensive account of the solvent governed distinct exciton coupling and symmetry breaking charge separation in a near-orthogonal perylenimide dimer (PP) is presented employing steady-state, femtosecond transient absorption measurements and quantum chemical calculations. Steady-state absorption measurements of the PP dimer reveal apparent electronic coupling between the two monomeric units, wherein the fluorescence measurements reveal a strong fluorescence character in nonpolar solvent, but a significantly quenched state is observed in polar solvent. Ultrafast transient absorption measurements reveal that the fluorescence quenching in polar solvent arises from a photoinduced symmetry-breaking charge transfer (SBCT) process and a subsequent population of the charge-separated radical ion-pair state. Contrastingly, in nonpolar solvent, the charge transfer is endothermic and energetically not feasible. Manifestly, the dimer in nonpolar solvent undergoes a conformational planarization within 20 ps accompanied by excitation delocalization over the two identical monomers in the lowest excited singlet state as evident from the dominant stimulated emission (around 580 nm) and the excited-state absorption (around 740 nm) in the femtosecond transient absorption spectra. Observed solvent-mediated selective control on the excited-state relaxation pathways in the near-orthogonal PP dimer can help shed light on the mechanisms of energy/charge transfer in molecular systems and guide the design of novel high-performance photovoltaic materials.

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“…Excimers can form when chromophores are cofacially stacked, resulting in strong electronic and excitonic coupling, and SB-CS can occur when strong CT interactions are dominant . Perylene − and perylene-based chromophores such as perylenediimides − (PDIs) as well as their longer homologue terrylenediimides , (TDIs) are often used to study photoinduced SB-CS and excimer formation. These and related chromophores ,− are good model compounds to study the balance and interplay between different types of interchromophore coupling that determine the fate of the electronic excited state.…”

Section: Introductionmentioning

confidence: 99%

Excited-State Dynamics of Perylene-Based Chromophore Assemblies on Nanoporous Anodic Aluminum Oxide Membranes

et al. 2021

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Exploring excited-state decay pathways in organic chromophore assemblies often requires significant synthetic effort to systematically change interchromophore distances. Moreover, the solubility of these assemblies is often limited. Herein, we examine how nanoporous anodic aluminum oxide (AAO) membranes can address both of these issues by covalently attaching 3-(phenylethynyl)perylene (PEP) and 1,6,7,12-tetrakis-(4-tert-butylphenoxy)perylene(3,4:9,10)-bis(dicarboximide) (tpPDI) chromophores with different loadings to AAO membranes, where the estimated average distance between chromophores on the AAO membranes for PEP-AAO-1, -2, and -3 is 5, 8, and 16 Å, respectively, while that between tpPDI cores in tpPDI-AAO-1, -2, -3, and -4 is 4, 6, 10, and 17 Å, respectively. When PEP-AAO-1, -2, and -3 are photoexcited, we observe a distribution of excimer-like states with varying degrees of charge-transfer (CT) character depending on the interchromophore spacing and solvent polarity. Increasing solvent polarity or decreasing the interchromophore distance increases the CT character in the excimer state. Notably, a PEP excimer state having significant CT character still forms in air, that is, in the absence of solvent. In contrast, when tpPDI-AAO-1 is photoexcited in solvents of varying polarity, as well as in air, we observe full symmetry-breaking charge separation (SB-CS) between tpPDIs attached to the AAO membrane. The SB-CS and charge recombination rates increase with increasing solvent polarity as the energy of the CT state is lowered. As the average distance between the tpPDIs increases in the series tpPDI-AAO-1, -2, -3, and -4, the SB-CS rate decreases with no SB-CS observed in tpPDI-AAO-4. This demonstrates the utility of AAO membranes to control the fate of electronic excited states by tuning the various contributions from Coulombic and charge transfer coupling.

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Interchromophore Rotation-Related Ultrafast Charge Separation at Excited States in Head-to-Tail Linked Perylene Diimide Dyads

Cited by 12 publications

References 28 publications

Linker dependent symmetry breaking charge separation in 9,10-bis(phenylethynyl)anthracene dimers

Linker dependent symmetry breaking charge separation in 9,10-bis(phenylethynyl)anthracene dimers

Distinct Excited-State Dynamics of Near-Orthogonal Perylenimide Dimer: Conformational Planarization versus Symmetry Breaking Charge Transfer

Excited-State Dynamics of Perylene-Based Chromophore Assemblies on Nanoporous Anodic Aluminum Oxide Membranes

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