Quantitative analyses of optically induced birefringence in azo dye containing polymers

Elhani, Sanaa; Maouli, Imad; Refki, Siham; Halim, Mohammed; Hayashi, Shinji; Sekkat, Zouheir

doi:10.1088/2040-8986/ab42b8

Cited by 9 publications

(16 citation statements)

References 48 publications

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“…pump polarization, and when PIB; e.g. Δn, is small (Δn is smaller than 0.01 in our case), it is given by 62 πλ Δ = n I d / pr . Where d is the thickness of the film, and I is normalized by the intensity of the probe light incident on the sample.…”

Section: Scientific Reports |mentioning

confidence: 76%

“…2(a). Details of the setup can be found in 62 . Briefly, the sample studied was positioned between two crossed-polarizers to observe transmitted light; e.g.…”

Section: Resultsmentioning

confidence: 99%

“…The films were eventually heated to remove the remaining solvent and their thicknesses and absorbances were measured by a profilometer and spectrophotometer; respectively. Details of sample preparation and characterization can be found in 62 .…”

Section: Methodsmentioning

confidence: 99%

“…The slope, p, and the molecular geometrical order parameter A t 2 of the early time evolution (ETE) of Δn; i.e. Δn ETE , are also proportional to these parameters 62 .…”

Section: Scientific Reports |mentioning

confidence: 99%

“…Detailed explanations of the phenomena associated PIB; e.g. optically induced dye orientation by photo-selective isomerization and how to correlate PIB to Δn measurement can be found in 62 . The expressions of k 1,2 and p (Eq.…”

Section: Scientific Reports |mentioning

confidence: 99%

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Surface Enhanced Visible Absorption of Dye Molecules in the Near-Field of Gold Nanoparticles

Elhani

Ishitobi

Inouye

et al. 2020

Sci Rep

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Surface enhanced absorption is a plasmonic effect parenting to surface enhanced fluorescence and Raman scattering, and it was clearly reported to occur in the infrared region of the spectrum of light. In this paper, we unambiguously show that it also occurs in the visible region of the spectrum by using a dye; i.e. an azo-dye, which exhibits a good light absorption in that region, and gold nanoparticles, which act as plasmonic nanoantennas that capture and re-radiate light, when the azo-dyes and the nanoparticles are incorporated in the bulk of solid films of polymer. In such a configuration, it is possible to use a dye concentration much larger than that of the nanoparticles and absorption path lengths much larger than those of the molecularly thin layers used in surface enhanced effects studies. In addition, the dye undergoes shape and orientation change; i.e. isomerization and reorientation, upon polarized light absorption; and the observation of surface enhanced visible absorption is done by two separate experiments; i.e. UV-visible absorption spectroscopy and photo-induced birefringence, since the signals detected from both experiments are directly proportional to the extinction coefficient of the dye. Both the dye's absorption and photoorientation are enhanced by the presence of the nanoparticles.electrical current when integrated in photovoltaic cells 27 . Gold NPs (Au-NPs) have been used for enhancing photovoltaic properties of dye-sensitized solar cells 28,29 and perovskite solar cells 30 , as well as in photocatalysis and environmental remediation [13][14][15]31,32 , and plasmonic photothermal therapy of cancer 33 as well as applications in imaging, sensing, biology and medicine 20 . Thin films containing photoresponsive units act as transducers that can convert incident light into molecular motion, resulting in numerous applications such as holography and data storage, as well as photomechanics and mass motion and micro-nano machines [34][35][36][37][38][39] , and so on 40,41 . For optically thin films, increasing the absorption results in improved transduction. In this paper, we report on the plasmonic enhancement of absorption and photo-orientation of azo-dye molecules in the presence of Au-NPs embedded in solid polymer films. The azo-dyes absorb visible light efficiently and undergo molecular shape change; i.e. trans ↔cis photoisomerization, and reorientation upon light absorption; i.e. photoorientation 42,43 .Azo-dye containing materials have been studied extensively in the past decades owing to interest in both fundamental and applications aspects [44][45][46][47][48][49] , and recent reviews provide a comprehensive view about the progress of research in this field 40,41 , and few studies reported the use of metal and semi-conductor NPs to enhance optical storage in azo-polymers 50,51 . The study reported in this paper is along the series of the studies, carried out by our group, which combine photo-reactivity in layered dielectric organic materials and plasmonic materials, including metals and ...

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Section: Scientific Reports |mentioning

confidence: 76%

“…2(a). Details of the setup can be found in 62 . Briefly, the sample studied was positioned between two crossed-polarizers to observe transmitted light; e.g.…”

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“…The slope, p, and the molecular geometrical order parameter A t 2 of the early time evolution (ETE) of Δn; i.e. Δn ETE , are also proportional to these parameters 62 .…”

Section: Scientific Reports |mentioning

confidence: 99%

Section: Scientific Reports |mentioning

confidence: 99%

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Surface Enhanced Visible Absorption of Dye Molecules in the Near-Field of Gold Nanoparticles

Elhani

Ishitobi

Inouye

et al. 2020

Sci Rep

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Azobenzene‐containing liquid crystalline poly(methacrylates) with different spacer length as media for holographic grating recording

Bugakov,

Shibaev,

Boiko

2024

Journal of Polymer Science

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Liquid crystalline (LC) poly(methacrylates) with azobenzene moieties in their side chains have been synthesized and their chemical structure has been confirmed with nuclear magnetic resonance spectroscopy and gel permeation chromatography. Azobenzene moieties are linked to polymer backbone via an alkyl spacer with length from 2 to 10 methylene units. Photooptical processes in thin amorphized polymer films are examined through measurements of optical anisotropy and holographic grating recording. Birefringence values induced with a linearly polarized green (532 nm) laser beam has strongly depended from the spacer length. Irradiation with two circularly polarized green laser beams leads to the formation of polarization and surface relief gratings, which have been visualized with polarized optical and atomic force microscopy, respectively. Diffraction efficiency of the recorded gratings is in correlation with the spacer length, namely, the shorter the spacer, the higher diffraction efficiency can be achieved. For polymers with short spacers polarization gratings can be easily erased by circularly polarized light, but only partial erasing of surface relief gratings is observed. The results presented offer the possibility of tailoring the chemical structure of azobenzene‐containing polymers for designing high‐efficiency media for the holographic recording.

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Enhancement of molecular mobility in solid polymers by light: fundamentals and applications

Sekkat

2022

Appl. Phys. B

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Quantitative analyses of optically induced birefringence in azo dye containing polymers

Cited by 9 publications

References 48 publications

Surface Enhanced Visible Absorption of Dye Molecules in the Near-Field of Gold Nanoparticles

Surface Enhanced Visible Absorption of Dye Molecules in the Near-Field of Gold Nanoparticles

Azobenzene‐containing liquid crystalline poly(methacrylates) with different spacer length as media for holographic grating recording

Enhancement of molecular mobility in solid polymers by light: fundamentals and applications

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