Nanostructuration of carbonaceous dust as seen through the positions of the 6.2 and 7.7<i>μ</i>m AIBs

Carpentier, Y.; Féraud, Géraldine; Dartois, E.; Brunetto, R.; Charon, E.; Cao, Ang; D’Hendecourt, L.; Bréchignac, Ph.; Rouzaud, Jean-Noël; Pino, T.

doi:10.1051/0004-6361/201118700

Cited by 76 publications

(81 citation statements)

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“…6, we show the strong correlation (r 2 = 0.89) between the ω c (aromatic C=C stretch) and ω c (sp 3 defect) band positions, confirming previous findings (Carpentier et al 2012). This relation traces differences in shapes and structures of the polyaromatic units in the soot.…”

Section: Relationships Among the Uv And Mid-ir Fit Parameterssupporting

confidence: 91%

“…6. Correlation between the carbon defect band, ω c (sp 3 defect), versus the aromatic C=C stretching band, ω c (C=C), verifying previous findings in other soot samples (Carpentier et al 2012). …”

Section: Relationships Among the Uv And Mid-ir Fit Parameterssupporting

confidence: 88%

“…carbon defects (Carpentier et al 2012) and contribute to electronic intra-band states of the material. For our samples, this band appears between 1190-1280 cm −1 .…”

Section: Relationships Among the Uv And Mid-ir Fit Parametersmentioning

confidence: 99%

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Polyaromatic disordered carbon grains as carriers of the UV bump: Far-UV to mid-IR spectroscopy of laboratory analogs

Gavilan

Pino

et al. 2017

A&A

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Context. A multiwavelength study of laboratory carbons with varying degrees of hydrogenation and sp 2 hybridization is required to characterize the structure of the carbonaceous carriers of interstellar and circumstellar extinction. Aims. We study the spectral properties of carbonaceous dust analogs from the far-ultraviolet to the mid-infrared and correlate features in both spectral ranges to the aromatic/aliphatic degree. Methods. Analogs to carbonaceous interstellar dust encountered in various phases of the interstellar medium have been prepared in the laboratory. These are amorphous hydrogenated carbons (a-C:H), analogs to the diffuse interstellar medium component, and soot particles, analogs to the polyaromatic component. Thin films (d < 100 nm) have been measured in transmission in the vacuumultraviolet (VUV; 120-210 nm) within the atmospheric pressure experiment (APEX) chamber of the DISCO beam line at the SOLEIL synchrotron radiation facility. Spectra of these films were further measured through the UV-Vis (210 nm-1 µm) and in the mid-infrared (3-15 µm). Results. Tauc optical gaps, E g , are derived from the visible spectra. The major spectral features are fitted through the VUV to the midinfrared to obtain positions, full-widths at half maximum (FWHM), and integrated intensities. These are plotted against the position of the π-π * electronic transitions peak. Unidentified or overlapping features in the UV are identified by correlations with complementary infrared data. A correlation between the optical gap and position of the π-π * electronic transitions peak is found. The latter is also correlated to the position of the sp 3 carbon defect band at ∼8 µm, the aromatic C=C stretching mode position at ∼6 µm, and the H/C ratio. Conclusions. Ultraviolet and infrared spectroscopy of structurally diverse carbon samples are used to constrain the nanostructural properties of carbon carriers of both circumstellar and interstellar extinction, such as the associated coherent lengths and the size of polyaromatic units. Our study suggests that carriers of the interstellar UV bump should exhibit infrared bands akin to the A/B classes of the aromatic infrared bands, while the circumstellar bump carriers should exhibit bands corresponding to the B/C classes.

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Section: Relationships Among the Uv And Mid-ir Fit Parameterssupporting

confidence: 91%

Section: Relationships Among the Uv And Mid-ir Fit Parameterssupporting

confidence: 88%

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Polyaromatic disordered carbon grains as carriers of the UV bump: Far-UV to mid-IR spectroscopy of laboratory analogs

Gavilan

Pino

et al. 2017

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“…From this, the calculated aliphatic N(CH 2 )/N(CH 3 ) ratio = 7 ± 3. Using the oscillator strength for the aromatic CH vibrational mode at 3.289 μm, A(CH) = 1.9 × 10 −18 cm/group (Joblin et al 1994), we find N(CH) arom /N(CH 2,3 ) aliph = 1.1 ± 0.3, in agreement with Carpentier et al (2012). Using the band strengths from methyl-substituted PAHs (Yang et al 2013), we find N(CH) arom /N(CH 2,3 ) aliph = 0.96 ± 0.2.…”

Section: Mid-infrared Spectra: A-c:hs and Sootssupporting

confidence: 75%

“…The intimate structures of the carriers of these different classes of AIBs are still unknown, although they are probably built on a polyaromatic skeleton spanning sizes from large molecules to small nanograins (Leger & Puget 1984;Allamandola et al 1985;Goto et al 2007;Sloan et al 2007;Pino et al 2008;Tielens 2008;Joblin & Tielens 2011;Li & Draine 2012;Carpentier et al 2012;Yang et al 2013).…”

Section: General Overviewmentioning

confidence: 99%

VUV spectroscopy of carbon dust analogs: contribution to interstellar extinction

Gavilan

Alata

et al. 2016

A&A

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Context.A full spectral characterization of carbonaceous dust analogs is necessary to understand their potential as carriers of observed astronomical spectral signatures such as the ubiquitous UV bump at 217.5 nm and the far-ultraviolet (FUV) rise common to interstellar extinction curves. Aims. Our goal is to study the spectral properties of carbonaceous dust analogs from the FUV to the mid-infrared (MIR) domain. We seek in particular to understand the spectra of these materials in the FUV range, for which laboratory studies are scarce. Methods. We produced analogs to carbonaceous interstellar dust encountered in various phases of the interstellar medium: amorphous hydrogenated carbons (a-C:H), for carbonaceous dust observed in the diffuse interstellar medium, and soot particles, for the polyaromatic component. Analogs to a-C:H dust were produced using a radio-frequency plasma reactor at low pressures, and soot nanoparticles films were produced in an ethylene (C 2 H 4 ) flame. We measured transmission spectra of these thin films (thickness <100 nm) in the far-ultraviolet (190−250 nm) and in the vacuum-ultraviolet (VUV; 50−190 nm) regions using the APEX chamber at the DISCO beam line of the SOLEIL synchrotron radiation facility. These were also characterized through infrared microscopy at the SMIS beam line. Results. We successfully measured the transmission spectra of these analogs from λ = 1 μm to 50 nm. From these, we extracted the laboratory optical constants via Kramers-Kronig inversion. We used these constants for comparison to existing interstellar extinction curves. Conclusions. We extend the spectral measurements of these types of carbonaceous analogs into the VUV and link the spectral features in this range to the 3.4 μm band. We suggest that these two materials might contribute to different classes of interstellar extinction curves.

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Activated Carbon Obtained from Bamboo: Synthesis, Morphological, Vibrational, and Electrical Properties and Possible Temperature Sensor

Arias‐Niquepa

Prías‐Barragán

Calderón

et al. 2019

Physica Status Solidi (a)

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In order to develop a new temperature sensor based on activated carbon (AC) samples, this work presents the synthesis, basic properties, and temperature sensor characteristics as possible future application. The AC samples are obtained from bamboo as source material via thermal decomposition method, under a controlled nitrogen low-atmosphere, at different carbonization temperatures and activated by using NaOH at 973 K. The basic properties are studied by using SEM, EDS, BET, X-ray diffraction, FTIR, Raman, and electrical techniques. It is found that AC exhibits morphological behavior of particles with vascular characteristics. The structural and vibrational responses suggest graphite oxide domains present in AC. Electrical characterization revealed a two-order of magnitude increase in conductivity, possibly attributed to increased graphite oxide domains produced by desorption of some organic compounds, which benefits development of temperature sensors with negative temperature coefficient (NTC). A possible temperature sensor based on AC is proposed and implemented. The electrical resistivity of AC, as temperature sensor, exhibits a NTC at À4.7%/K, with linear current response varying from 21.1 to 37.2 mA, which is a novelty for a thermistor NTC. These results suggest that AC is an excellent candidate to develop temperature sensors in electronics.

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Nanostructuration of carbonaceous dust as seen through the positions of the 6.2 and 7.7μm AIBs

Cited by 76 publications

References 85 publications

Polyaromatic disordered carbon grains as carriers of the UV bump: Far-UV to mid-IR spectroscopy of laboratory analogs

Polyaromatic disordered carbon grains as carriers of the UV bump: Far-UV to mid-IR spectroscopy of laboratory analogs

VUV spectroscopy of carbon dust analogs: contribution to interstellar extinction

Activated Carbon Obtained from Bamboo: Synthesis, Morphological, Vibrational, and Electrical Properties and Possible Temperature Sensor

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