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44 results on '"Barsella A"'

1. Robust coherent dynamics of homogeneously limited anisotropic excitons in two-dimensional layered ReS2

Author

Chowdhury, Rup Kumar, Islam, Md Samiul, Barthelemy, Marie, Beyer, Nicolas, Engel, Lorry, Pelle, Jean-Sebastien, Rastei, Mircea, Barsella, Alberto, and Fras, Francois

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, Physics - Optics, Quantum Physics
Abstract

The discovery of in-plane anisotropic excitons in two-dimensional layered semiconductors enables state-of-the-art nanophotonic applications. A fundamental yet unknown parameter of these quasiparticles is the coherence time (T_2 ), which governs the quantum dephasing timescale, over which the coherent superposition of excitons can be maintained and manipulated. Here, we report the direct measurement of T_2 within the sub-picosecond range, along with multiple population decay timescales (T_1 ) at resonance for anisotropic excitons in pristine layered rhenium disulfide (ReS2). We observe a notable weak dependence on layer thickness for T_2 , and a quasi-independence for T_1 . The excitonic coherence in few-layer ReS2 exhibits exceptional robustness against optical density and temperature compared to other two-dimensional semiconductors, enabling quantum features even at room temperature. No photon echo fingerprints were observed in pristine ReS2, highlighting the homogeneous character of the anisotropic excitonic transitions and a particularly low level of disorder in exfoliated flakes. Lastly, our results for mono- to bulk-like ReS2 support a direct gap band structure regardless their layer thickness, addressing the ongoing discussion about its nature.

Published
2024

2. Large-Scale Statistical Analysis of Defect Emission in hBN: Revealing Spectral Families and Influence of Flakes Morphology

Author

Islam, M. S., Chowdhury, R. K., Barthelemy, M., Moczko, L., Hebraud, P., Berciaud, S., Barsella, A., and Fras, F.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

Quantum emitters in two-dimensional layered hexagonal boron nitride are quickly emerging as a highly promising platform for next-generation quantum technologies. However, precise identification and control of defects are key parameters to achieve the next step in their development. We conducted a comprehensive study by analyzing over 10,000 photoluminescence emission lines, revealing 11 distinct defect families within the 1.6 to 2.2 eV energy range. This challenges hypotheses of a random energy distribution. We also reported averaged defect parameters, including emission linewidths, spatial density, phonon side bands, and the Debye-Waller factors. These findings provide valuable insights to decipher the microscopic origin of emitters in hBN hosts. We also explored the influence of hBN host morphology on defect family formation, demonstrating its crucial impact. By tuning flake size and arrangement we achieve selective control of defect types while maintaining high spatial density. This offers a scalable approach to defect emission control, diverging from costly engineering methods. It highlights the importance of investigating flake morphological control to gain deeper insights into the origins of defects and to expand the spectral tailoring capabilities of defects in hBN.

Published
2023
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4. Cover

Author

Barsella, Susanna and Marchesi, Simone

Published
2022

5. Index of Names

Author

Barsella, Susanna and Marchesi, Simone

Published
2022

6. Index Locorum

Author

Barsella, Susanna and Marchesi, Simone

Published
2022

8. Bibliography

Author

Barsella, Susanna and Marchesi, Simone

Published
2022

16. Introduction

Author

Barsella, Susanna and Marchesi, Simone

Published
2022

21. Half Title Page

Author

Barsella, Susanna and Marchesi, Simone

Published
2022

28. Synthesis and Optical Characterization of Hydrazone-Substituted Push–Pull-Type NLOphores

Author

Erden, Kübra, Soyler, Dilek, Barsella, Alberto, Şahin, Onur, Soylemez, Saniye, and Dengiz, Cagatay

Abstract

Two distinct families of NLOphores featuring hydrazone donors were synthesized using click-type [2 + 2] cycloaddition retroelectrocyclizations (CA-RE). Despite the limitations in the substrate scope, it was shown for the first time that hydrazone-activated alkynes could undergo reactions with TCNE/TCNQ. The electrochemical, photophysical, and second-order nonlinear optical (NLO) characteristics of the chromophores were analyzed utilizing experimental and computational approaches. Chromophores 17–21and 23–27exhibited two reduction waves, along with one oxidation wave that can be attributed to the hydrazone moiety. All chromophores exhibit charge-transfer bands extending from the visible to the near-infrared region. The λmaxof hydrazone-based chromophores falls within the range of 473 to 725 nm. Additionally, all chromophores exhibited positive solvatochromism. Computational studies have been performed to elucidate the origin of the low-energy absorption bands. Parameters such as dipole moment, band gaps, electronegativity, global chemical hardness/softness, average polarizability, and first hyperpolarizability were calculated to obtain information about NLO properties of the target structures. The thermal stabilities of the NLOphores were assessed through TGA. Experimental NLO measurements were conducted using the electric field-induced second harmonic generation (EFISHG) technique. The studied structures demonstrated NLO responses, with μβ values between 520 × 10–48esu and 5300 × 10–48esu.

Published
2024
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29. Push–Pull Derivatives Based on 2,4′-Biphenylene Linker with Quinoxaline, [1,2,5]Oxadiazolo[3,4-B]Pyrazine and [1,2,5]Thiadiazolo[3,4-B]Pyrazine Electron Withdrawing Parts

Author

Egor V. Verbitskiy, Pascal le Poul, Filip Bureš, Sylvain Achelle, Alberto Barsella, Yuriy A. Kvashnin, Gennady L. Rusinov, and Valery N. Charushin

Subjects
furazanopyrazine, [1,2,5]thiadiazolo[3,4-b]pyrazine, quinoxaline, donor–acceptor systems, twisted intramolecular charge transfer, Organic chemistry, QD241-441
Abstract

A series of novel V-shaped quinoxaline, [1,2,5]oxadiazolo[3,4-b]pyrazine and [1,2,5]thiadiazolo[3,4-b]pyrazine push–pull derivatives with 2,4′-biphenylene linker were designed and their electrochemical, photophysical and nonlinear optical properties were investigated. [1,2,5]Oxadiazolo[3,4-b]pyrazine is the stronger electron-withdrawing fragment as shown by electrochemical, and photophysical data. All compounds are emissive in a solid-state (from the cyan to red region of the spectrum) and quinoxaline derivatives are emissions in DCM solution. It has been found that quinoxaline derivatives demonstrate important solvatochromism and extra-large Stokes shifts, characteristic of twisted intramolecular charge transfer excited state as well as aggregation induced emission. The experimental conclusions have been justified by theoretical (TD-)DFT calculations.

Published
2022
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31. Push-Pull Derivatives Based on 2,4 '-Biphenylene Linker with Quinoxaline, [1,2,5]Oxadiazolo[3,4-B]Pyrazine and [1,2,5]Thiadiazolo[3,4-B]Pyrazine Electron Withdrawing Parts

Author

Verbitskiy, Egor V, le Poul, Pascal, Bureš, Filip, Achelle, Sylvain, Barsella, Alberto, Kvashnin, Yuriy A, Rusinov, Gennady L, Charushin, Valery N, Verbitskiy, Egor V, le Poul, Pascal, Bureš, Filip, Achelle, Sylvain, Barsella, Alberto, Kvashnin, Yuriy A, Rusinov, Gennady L, and Charushin, Valery N

Abstract

A series of novel V-shaped quinoxaline, [1,2,5]oxadiazolo[3,4-b]pyrazine and [1,2,5]thiadiazolo[3,4-b]pyrazine push-pull derivatives with 2,4 '-biphenylene linker were designed and their electrochemical, photophysical and nonlinear optical properties were investigated. [1,2,5]Oxadiazolo[3,4-b]pyrazine is the stronger electron-withdrawing fragment as shown by electrochemical, and photophysical data. All compounds are emissive in a solid-state (from the cyan to red region of the spectrum) and quinoxaline derivatives are emissions in DCM solution. It has been found that quinoxaline derivatives demonstrate important solvatochromism and extra-large Stokes shifts, characteristic of twisted intramolecular charge transfer excited state as well as aggregation induced emission. The experimental conclusions have been justified by theoretical (TD-)DFT calculations., Byla připravena série nových push-pull derivátů na bázi chinoxalinu, [1,2,5]oxadiazolo[3,4-b]pyrazinu a [1,2,5]thiadiazolo[3,4-b]pyrazinu s 2,4 '-bifenylenovým linkerem a byly studovány jejich elektrochemické, fotofyzikální a nelineárně optické vlastnosti. Experientální výsledky byly porovnány s teoretickými DFT kalkulacemi.

Published
2023

32. Exploratory Mixed-Methods Study of a Primary Care–Based Intervention Promoting Shared Reading During Infancy

Author

Clare C. Crosh, Adam Barsella, Leah Van Slambrouck, Patricia M. Notario, Yi Li, Allison A. Parsons, and John S. Hutton

Subjects
Literacy, Primary Health Care, Reading, Surveys and Questionnaires, Pediatrics, Perinatology and Child Health, Infant, Newborn, Humans, Infant, Parent-Child Relations, Child
Abstract

Parent-child “shared” reading can be a rich source of language exposure. Clinic-based programs, notably Reach Out and Read (ROR), are intended to enhance this. However, ROR has been traditionally introduced at 6 months and only recently expanded to younger ages. This study explored efficacy of an intervention delivered during pediatric well visits promoting shared reading prior to 6 months old, in terms of home reading attitudes and routines. The intervention group received children’s books and anticipatory guidance about benefits of shared reading, whereas the control group received general age-related anticipatory guidance. Surveys were administered at the child’s newborn (pre-intervention) and 6-month (post-intervention) well visits. Significant findings at 6 months included more frequent shared reading ( P = .03), greater comfort reading at this age ( P = .01), and greater importance attributed to shared reading ( P = .04) in the intervention group relative to controls. These support the expansion of early literacy interventions such as ROR into early infancy.

Published
2022
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37. Photovoltaic and photothermal effects induced by visible laser radiation in atomic force microscopy probes

Author

M.D. Pichois, X. Henning, M.A. Hurier, M. Vomir, A. Barsella, L. Mager, B. Donnio, J.L. Gallani, and M.V. Rastei

Subjects
Instrumentation, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials
Abstract

Excitation of electrons into higher energy states in solid state materials can be induced by absorption of visible light, a physical process generally studied by optical absorption spectroscopy. A promising approach for improving the spatial resolution of optical absorption spectroscopy beyond the diffraction limit is the detection of photoinduced forces by an atomic force microscope operating under wavelength-dependent light irradiation. Here, we report on a combined photovoltaic/photothermal effect induced by the absorption of visible light by the microscope probes. By monitoring the photoinduced modifications of the oscillation of the probes, it is found that the oscillation phase-voltage parabolic signals display specific fingerprints which depend on light intensity and the nature of the materials composing the probes. In particular, a localized surface photovoltage (SPV) is evidenced at the tip apex of uncoated Si probes, while none is observed on Au-coated Si probes. The photothermal effects are distinguished from photovoltaic effects by specific shifts of the phase-voltage parabolas. The findings are relevant for the whole range of atomic force microscopy techniques making use of visible light as an additional means of local optical characterization.

Published
2022

38. Push–Pull Derivatives Based on 2,4′-Biphenylene Linker with Quinoxaline, [1,2,5]Oxadiazolo[3,4-B]Pyrazine and [1,2,5]Thiadiazolo[3,4-B]Pyrazine Electron Withdrawing Parts

Author

Verbitskiy, E. V., Le Poul, P., Bureš, F., Achelle, S., Barsella, A., Kvashnin, Y. A., Rusinov, G. L., Charushin, V. N., Verbitskiy, E. V., Le Poul, P., Bureš, F., Achelle, S., Barsella, A., Kvashnin, Y. A., Rusinov, G. L., and Charushin, V. N.

Abstract

A series of novel V-shaped quinoxaline, [1,2,5]oxadiazolo[3,4-b]pyrazine and [1,2,5]thia-diazolo[3,4-b]pyrazine push–pull derivatives with 2,4′-biphenylene linker were designed and their electrochemical, photophysical and nonlinear optical properties were investigated. [1,2,5]Oxadia-zolo[3,4-b]pyrazine is the stronger electron-withdrawing fragment as shown by electrochemical, and photophysical data. All compounds are emissive in a solid-state (from the cyan to red region of the spectrum) and quinoxaline derivatives are emissions in DCM solution. It has been found that quinoxaline derivatives demonstrate important solvatochromism and extra-large Stokes shifts, characteristic of twisted intramolecular charge transfer excited state as well as aggregation induced emission. The experimental conclusions have been justified by theoretical (TD-)DFT calculations. © 2022 by the authors. Li-censee MDPI, Basel, Switzerland.

Published
2022

39. V-Shaped Methylpyrimidinium Chromophores for Nonlinear Optics

Author

Achelle, Sylvain, Verbitskiy, Egor V, Fecková, Michaela, Bureš, Filip, Barsella, Alberto, Robin-le Guen, Francoise, Achelle, Sylvain, Verbitskiy, Egor V, Fecková, Michaela, Bureš, Filip, Barsella, Alberto, and Robin-le Guen, Francoise

Abstract

A series of four V-shaped methylpyrimidinium salts bearing diphenylamino-electron-donating groups appended at various pyrimidine positions were designed. These chromophores were obtained by regioselective N(1) monomethylation by methyl methanesulfonate of the pyrimidine core. Linear optical properties were studied experimentally and electronic properties were further completed by (TD)-DFT calculations. The second-order nonlinear optical (NLO) properties were also studied using electric field induced second harmonic generation (EFISH) method in chloroform, and all pyrimidinium salts exhibited mu beta(0)>1000x10(-48) esu. The 2,4-disubstituted pyrimidinium core is preferred over 4,6-disubstitution as it enhances the NLO response and increases the dipole moment. (E,E)-2,4-Bis[4-(diphenylamino)styryl]-1-methylpyrimidin-1-ium methanesulfonate appears to be the best NLO-phore in chloroform in the series (mu beta(0)=2500x10(-48) esu) and a figure of merit mu beta(0)/MW=3.4 10(-48) esu mol g(-1)., Byla připravena série čtyř methypyrimidiniových solí tvaru písmene V nesoucích elektrondonorní difenylaminoskupiny v různých polohách pyrimidiniového jádra. Syntéza byla jvedena jako regioselektivní N(1) methylace methyl-methansulfonátem. Byly měřeny lineárně-optické vlastnosti a elektronové vlastnosti byly konfrontovány s DFT kalkulacemi.

Published
2022

40. Synthesis, photophysical and nonlinear optical properties of [1,2,5] oxadiazolo[3,4-b]pyrazine-based linear push-pull systems

Author

Verbitskiy, Egor V, Achelle, Sylvain, Bureš, Filip, le Poul, Pascal, Barsella, Alberto, Kvashnin, Yuriy A, Rusinov, Gennady L, Robin-le Guen, Francoise, Chupakhin, Oleg N, Charushin, Valery N, Verbitskiy, Egor V, Achelle, Sylvain, Bureš, Filip, le Poul, Pascal, Barsella, Alberto, Kvashnin, Yuriy A, Rusinov, Gennady L, Robin-le Guen, Francoise, Chupakhin, Oleg N, and Charushin, Valery N

Abstract

A series of D-pi-A chromophores based on [1,2,5]oxadiazolo[3,4-b]pyrazine electron-withdrawing group has been designed. The influence of the pi-conjugated linker (1,4-phenylene and 2,5-thienylene) and the amino-electron-donating group (diphenylamino and carbazol-9-yl) was studied by cyclic voltammetry, UV-Vis and emission spectroscopy. The second order nonlinear optical properties were also studied using the electric field induced second harmonic generation (EFISH) method. The experimental results have been rationalized by theoretical DFT calculations., Byla připravena série D-pi-A chromoforů na bázi elektronakceptorního skeletu [1,2,5]oxadiazolo[3,4-b]pyrazinu. Prostřednictvím cyklické voltametrie, UV-Vis a emisní spectroskopie byl studován vliv pi-konjugovaného linkeru (1,4-fenylen and 2,5-thienylen) a elektrondonorního substituentu aminového typu (difenylamino and karbazol-9-yl). Experimentální data byla konfrontována s výsledky DFT kalkulací.

Published
2022

43. Push–Pull Derivatives Based on 2,4′-Biphenylene Linker with Quinoxaline, [1,2,5]Oxadiazolo[3,4- B ]Pyrazine and [1,2,5]Thiadiazolo[3,4- B ]Pyrazine Electron Withdrawing Parts.

Author

Verbitskiy, Egor V., le Poul, Pascal, Bureš, Filip, Achelle, Sylvain, Barsella, Alberto, Kvashnin, Yuriy A., Rusinov, Gennady L., and Charushin, Valery N.

Subjects
QUINOXALINES, INTRAMOLECULAR charge transfer, PYRAZINES, STOKES shift
Abstract

A series of novel V-shaped quinoxaline, [1,2,5]oxadiazolo[3,4-b]pyrazine and [1,2,5]thiadiazolo[3,4-b]pyrazine push–pull derivatives with 2,4′-biphenylene linker were designed and their electrochemical, photophysical and nonlinear optical properties were investigated. [1,2,5]Oxadiazolo[3,4-b]pyrazine is the stronger electron-withdrawing fragment as shown by electrochemical, and photophysical data. All compounds are emissive in a solid-state (from the cyan to red region of the spectrum) and quinoxaline derivatives are emissions in DCM solution. It has been found that quinoxaline derivatives demonstrate important solvatochromism and extra-large Stokes shifts, characteristic of twisted intramolecular charge transfer excited state as well as aggregation induced emission. The experimental conclusions have been justified by theoretical (TD-)DFT calculations. [ABSTRACT FROM AUTHOR]

Published
2022
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44. Dipolar NLO Chromophores Bearing Diazine Rings as π-Conjugated Linkers

Author

Klikar, Milan, le Poul, Pascal, Růžička, Aleš, Pytela, Oldřich, Barsella, Alberto, Dorkenoo, Kokou D., Robin-le Guen, Françoise, Bureš, Filip, and Achelle, Sylvain

Abstract

The synthesis of a series of push–pull derivatives bearing triphenylamine electron-donating group, cyclopenta[c]thiophen-4,6-dione electron acceptor and various π-linkers including (hetero)aromatic fragments is reported. All target chromophores with systematically varied π-linker structure were further investigated by electrochemistry, absorption measurements, and EFISH experiments in conjunction with DFT calculations. Based on electrochemical and photophysical measurements, when a polarizable 2,5-thienylene moiety is embedded into the chromophore π-backbone the highest intramolecular charge transfer (ICT) is observed. Benzene, pyrimidine, and pyridazine derivatives exhibit lower polarizability and extent of the ICT across these π-linkers. The elongation of the π-conjugated system via additional ethenylene linker results in a significant reduction of the HOMO–LUMO gap and an enhancement of the NLO response. Whereas it does not significantly influence electrochemical and linear optical properties, the orientation of the pyrimidine ring seems to be a key parameter on the μβvalue due to significant variation of the dipolar moment (μ) value. In 2aand 2c, pyrimidine is oriented to behave as an acceptor and thus generate dipolar molecule with μ above 5 D, whereas in 2band 2dground state dipole moment is significantly reduced. This study seems to indicate a high aromaticity of pyrimidine and pyridazine derivatives, close to the benzene analogues and significantly higher than thiophene analogues.

Published
2024
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