Environment‐Sensitive Behavior of DCNP in Solvents with Different Viscosity, Polarity and Proticity

Morawski, Olaf; Kozankiewicz, Β.; Miniewicz, Andrzej; Sobolewski, Andrzej L.

doi:10.1002/cphc.201500563

Cited by 11 publications

(16 citation statements)

References 42 publications

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“…Experimental studies and previous quantum mechanical calculations have shown that DCNP presents a photophysics, which depends on the polarity and viscosity of the environment. [ 9 ] A brighter fluorescence is found for nonpolar solvents and in more viscous environments, and ASE has been observed in a poly(methyl methacrylate) matrix, [ 10 ] suggesting DCNP as suitable dye for use in rigid matrices. In fact, DCNP presents the typical characteristics of a potential twisted‐internal‐charge‐transfer (TICT) system: an electron donor group (benzene ring), an electron attractor group (cyan groups), and a network of conjugated bonds that delocalize the electronic density, connecting the two subunits.…”

Section: Resultsmentioning

confidence: 99%

Dye Stabilization and Wavelength Tunability in Lasing Fibers Based on DNA

Persano

Szukalski

Gaio

et al. 2020

Advanced Optical Materials

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Lasers based on biological materials are attracting an increasing interest in view of their use in integrated and transient photonics. Deoxyribonucleic acid (DNA) as optical biopolymer in combination with highly emissive dyes has been reported to have excellent potential in this respect. However, achieving miniaturized lasing systems based on solid‐state DNA shaped in different geometries to confine and enhance emission is still a challenge, and the physicochemical mechanisms originating fluorescence enhancement are not fully understood. Herein, a class of wavelength‐tunable lasers based on DNA nanofibers is demonstrated, for which optical properties are highly controlled through the system morphology. A synergistic effect is highlighted at the basis of lasing action. Through a quantum chemical investigation, it is shown that the interaction of DNA with the encapsulated dye leads to hindered twisting and suppressed channels for the nonradiative decay. This is combined with effective waveguiding, optical gain, and tailored mode confinement to promote morphologically controlled lasing in DNA‐based nanofibers. The results establish design rules for the development of bright and tunable nanolasers and optical networks based on DNA nanostructures.

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Section: Resultsmentioning

confidence: 99%

Dye Stabilization and Wavelength Tunability in Lasing Fibers Based on DNA

Persano

Szukalski

Gaio

et al. 2020

Advanced Optical Materials

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“…This observation is likely connected with the strong push−pull character of the Lemke's chromophore derivative which in weak polar environment, such as DCM, could effectively dissipate excitation energy through the twist of dicyanoethenyl group. 29,38 Excitation and emission spectra of the investigated layered materials are shown in Figure 1. Ant-PMMA shows broad excitation bands, with maximum at λ ex = 520 nm.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Distributed Feedback Lasing in Amorphous Polymers with Covalently Bonded Fluorescent Dyes: The Influence of Photoisomerization Process

et al. 2017

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We present the synthesis and characterization of a new type of organic materials for light amplification purposes. These materials consist in branched polymers based on 9,10-bis(4-(diethylamino)phenylethynyl)anthracene or 2-(3-(4-(diethylamino)styryl)-5,5-dimethylcyclohex-2-enylidene)malononitrile chromophore cores with covalently attached poly(methyl methacrylate) chains, named Ant-PMMA and Lem-PMMA, respectively. In both cases, polymers with controlled molecular weight of about 30 kDa were synthesized by atom transfer radical polymerization (ATRP), using functionalized chromophores as initiators. Thin layers of the two polymers were fabricated by a simple drop-casting technique. We describe the spectroscopic properties of these materials and their ability for light amplification through the measurements of amplified spontaneous emission, random lasing process, and distributed feedback (DFB) lasing achieved via holographic-type excitation. Considering the different chemical structures of the chromophores, and related distinct interaction pathways with light, we postulate two slightly different DFB lasing mechanisms in investigated organic solid-state gain media. The Lem-PMMA ability to undergo photoisomerization, providing material refractive index modulation upon holographic-type pumping, is supposed to be responsible for superior DFB lasing performance as compared to Ant-PMMA, for which similar type of excitation results in lasing coupling solely dominated by gain modulation.

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“…There is a growing family of polarized molecular systems in which optical excitation to the 1 LE state can significantly increase the dipole moment of the system . Among these, a class of highly polarized molecular dyads composed of two coumarin moieties linked in a (donor–acceptor)–linker–(donor–acceptor) (DA‐L‐DA) orientation, recently studied by us, is particularly interesting.…”

Section: Introductionmentioning

confidence: 99%

Highly Polarized Coumarin Derivatives Revisited: Solvent‐Controlled Competition Between Proton‐Coupled Electron Transfer and Twisted Intramolecular Charge Transfer

Morawski

Kielesiński

Gryko

et al. 2020

Chemistry A European J

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Linking a polarized coumarin unit with an aromatic substituent via an amide bridge results in weak electronic coupling that affects the intramolecular electron‐transfer (ET) process. As a result of this, interesting solvent‐dependent photophysical properties can be observed. In polar solvents, electron transfer in coumarin derivatives of this type induces a mutual twist of the electron‐donating and ‐accepting molecular units (TICT process) that facilitates radiationless decay processes (internal conversion). In the dyad with the strongest intramolecular hydrogen bond, the planar form is stabilized, such that twisting can only occur in highly polar solvents, whereas a fast proton‐coupled electron‐transfer (PCET process) occurs in nonpolar n‐alkanes. The kPCET rate constant decreases linearly with the energy of the fluorescence maximum in different solvents. This observation can be explained in terms of competition between electron‐ and proton‐transfer from a highly polarized (ca. 15 D) and fluorescent locally excited (1LE) state to a much less polarized (ca. 4 D) charge‐transfer (1CT) state, a unique occurrence. Photophysical measurements performed for a family of related coumarin dyads, together with results of quantum‐chemical computations, give insight into the mechanism of the ET process, which is followed by either a TICT or a PCET process. Our results reveal that dielectric solvation of the excited state slows down the PCET process, even in nonpolar solvents.

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Environment‐Sensitive Behavior of DCNP in Solvents with Different Viscosity, Polarity and Proticity

Cited by 11 publications

References 42 publications

Dye Stabilization and Wavelength Tunability in Lasing Fibers Based on DNA

Dye Stabilization and Wavelength Tunability in Lasing Fibers Based on DNA

Distributed Feedback Lasing in Amorphous Polymers with Covalently Bonded Fluorescent Dyes: The Influence of Photoisomerization Process

Highly Polarized Coumarin Derivatives Revisited: Solvent‐Controlled Competition Between Proton‐Coupled Electron Transfer and Twisted Intramolecular Charge Transfer

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