Direct evidence of solvent polarity governing the intramolecular charge and energy transfer: ultrafast relaxation dynamics of push–pull fluorene derivatives

Neelambra, Afeefah U.; Govind, Chinju; Devassia, Tessy T.; Somashekharappa, Guruprasad M.; Karunakaran, Venugopal

doi:10.1039/c9cp00796b

Cited by 18 publications

(15 citation statements)

References 78 publications

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“…At 3×10 −4 M, 1 in n ‐decane exhibited an initial anisotropy value ( r 0 ) of 0.25 and reached the plateau region ( r ∞ ) at 0.13 by losing the anisotropy with a decay time, τ r =45 ps (Figure 4 h). The r 0 value of 0.25 at around zero time indicates that the initial orientation of the transition dipole moments has an angle of 30° [31] . On the other hand, at a similar concentration in MCH, the initial anisotropy ( r 0 ) was found to be 0.15, which reached the final anisotropy ( r ∞ ) value of −0.04 (Figure 4 g).…”

Section: Resultsmentioning

confidence: 88%

Tweaking a BODIPY Spherical Self‐Assembly to 2D Supramolecular Polymers Facilitates Excited‐State Cascade Energy Transfer

et al. 2021

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Excited state properties such as emission, exciton transport, electron transfer, etc., are strongly dependent on the shape, size and molecular arrangement of chromophore based supramolecular architectures. Herein, we demonstrate creation and control of distinct supramolecular energy landscapes for the reversible control of the excited‐state emission processes through cascade energy transfer in chromophore assemblies, facilitated by an unprecedented solvent effect. In methylcyclohexane, a tailor‐made Y‐shaped BODIPY derivative self‐assembles to form an unusual spherical architecture of 400–1200 nm size, which exhibits a single emission at 540 nm upon 475 nm excitation through a normal excitation deactivation process. However, in n‐decane, the same BODIPY derivative forms two‐dimensional supramolecular sheets, exhibiting multiple emission peaks at 540, 610, 650, 725 and 790 nm with 475 nm excitation due to cascade energy transfer. Further control on the morphology and excitation energy transfer is possible with variable solvent composition and ultrasound stimulation, resulting in enhanced near‐infrared emission with an overall pseudo Stokes shift of 7105 cm−1.

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Section: Resultsmentioning

confidence: 88%

Tweaking a BODIPY Spherical Self‐Assembly to 2D Supramolecular Polymers Facilitates Excited‐State Cascade Energy Transfer

et al. 2021

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“…Intramolecular charge transfer (ICT) molecular systems have attracted considerable interest over the last two decades because of their potential for technological applications in molecular electronics, solar cells, quantum optics, etc. − Considerable research efforts have been devoted to developing new advanced ICT molecules as a promising route to enhance charge transfer (CT) rate. − Parallel attention has been paid to the understanding of the CT mechanism in various molecular systems as it will provide a successful design strategy for new ICT molecules.…”

mentioning

confidence: 99%

Strong Electronic Coupling-Induced Ultrafast Charge Transfer in Donor–Pyrene–Acceptor Systems

Park

Sung

Kim

2021

J. Phys. Chem. Lett.

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In this study, we decipher the charge transfer (CT) processes in donor–pyrene–acceptor (DPA) molecules via various time-resolved spectroscopic measurements. It has been challenging to unravel the ultrafast CT dynamics in DPA molecules because they exhibit an initial CT emission in the same spectral range as the locally excited (LE) emission. However, we finally observed the CT rate of ∼200 fs in DPA molecules from the time-resolved fluorescence anisotropy decay profiles. Our measurements allow us to suggest that the LE and CT states of DPA systems have isoenergetic potential surfaces and that the introduction of the acceptor to the pyrene moiety gives rise to strong electronic coupling between the LE and CT states. Therefore, we determined that this solvent-independent ultrafast CT occurs through the adiabatic potential energy surface and that the CT characteristics are enhanced in DPA compared to the donor–pyrene–donor system.

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“…intensity along with a red shift and broadening in the SE band that is attributed to solvation and structural relaxation in the excited state of the selected isomer, based on an earlier literature report. [48][49][50][51] However, at a longer time delay (up to 1 ns), the ESA band at 591 nm diminishes and concomitantly the peak at 413 nm increases and is broadened, indicating the formation of the triplet state (T n ) at the expense of the singlet state, which is confirmed again using nanosecond transient absorption spectroscopy (vide infra). 52 Similar spectral observations were obtained for the meta isomer, as displayed in Fig.…”

Section: Systems Quenchermentioning

confidence: 83%

Effect of positional isomerism on the excited state charge transfer dynamics of anthracene-based D–π–A systems

Pratihar

Prasad

2023

Phys. Chem. Chem. Phys.

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Direct evidence of solvent polarity governing the intramolecular charge and energy transfer: ultrafast relaxation dynamics of push–pull fluorene derivatives

Abstract: The occurrence of intramolecular charge transfer along with energy transfer controlled by the polarity of solvent is revealed by femtosecond and nanosecond transient absorption and emission spectroscopy.

Cited by 18 publications

References 78 publications

Tweaking a BODIPY Spherical Self‐Assembly to 2D Supramolecular Polymers Facilitates Excited‐State Cascade Energy Transfer

Tweaking a BODIPY Spherical Self‐Assembly to 2D Supramolecular Polymers Facilitates Excited‐State Cascade Energy Transfer

Strong Electronic Coupling-Induced Ultrafast Charge Transfer in Donor–Pyrene–Acceptor Systems

Effect of positional isomerism on the excited state charge transfer dynamics of anthracene-based D–π–A systems

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