Terahertz time-domain spectroscopy as a novel metrology tool for liquid-phase exfoliated few-layer graphene

Skalsky, Stefan; Molloy, J. F.; Naftaly, Mira; Sainsbury, Toby; Paton, Keith R.

doi:10.1088/1361-6528/aae8ce

Cited by 14 publications

(14 citation statements)

References 72 publications

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“…The addition of 1-wt% graphene into the copolymer matrix increases the α(ω), especially at the high-frequency end of the spectrum. The latter result is in good agreement with previously published data [22].…”

Section: Dielectric Constantsupporting

confidence: 94%

“…Clearly, adding 1 wt% of graphene flakes to a copolymer matrix measurably increased (~10%) the n of the resultant nanocomposite. Similar results were obtained by other groups [21,22].…”

Section: Index Of Refraction and Absorption Coefficientsupporting

confidence: 91%

“…For example, it has been used to assess damage or detect defects in aeronautic components [18,19]. Further, several groups have proposed using this approach to analyze carbon nanotube and/or graphene-polymer nanocomposites to assess the level of dispersion of the nanofiller [20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

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Terahertz Time-Domain Spectroscopy of Graphene Nanoflakes Embedded in Polymer Matrix

et al. 2019

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The terahertz time-domain spectroscopy (THz-TDS) technique has been used to obtain transmission THz-radiation spectra of polymer nanocomposites containing a controlled amount of exfoliated graphene. Graphene nanocomposites (1 wt%) that were used in this work were based on poly(ethylene terephthalate-ethylene dilinoleate) (PET-DLA) matrix and were prepared via a kilo-scale (suitable for research and development, and prototyping) in-situ polymerization. This was followed by compression molding into 0.3-mm-thick and 0.9-mm-thick foils. Transmission electron microscopy (TEM) and Raman studies were used to confirm that the graphene nanoflakes dispersed in a polymer matrix consisted of a few-layer graphene. The THz-radiation transients were generated and detected using a low-temperature–grown GaAs photoconductive emitter and detector, both excited by 100-fs-wide, 800-nm-wavelength optical pulses, generated at a 76-MHz repetition rate by a Ti:Sapphire laser. Time-domain signals transmitted through the nitrogen, neat polymer reference, and 1-wt% graphene-polymer nanocomposite samples were recorded and subsequently converted into the spectral domain by means of a fast Fourier transformation. The spectral range of our spectrometer was up to 4 THz, and measurements were taken at room temperature in a dry nitrogen environment. We collected a family of spectra and, based on Fresnel equations, performed a numerical analysis, that allowed us to extract the THz-frequency-range refractive index and absorption coefficient and their dependences on the sample composition and graphene content. Using the Clausius-Mossotti relation, we also managed to estimate the graphene effective dielectric constant to be equal to ~7 ± 2. Finally, we extracted from our experimental data complex conductivity spectra of graphene nanocomposites and successfully fitted them to the Drude-Smith model, demonstrating that our graphene nanoflakes were isolated in their polymer matrix and exhibited highly localized electron backscattering with a femtosecond relaxation time. Our results shed new light on how the incorporation of exfoliated graphene nanoflakes modifies polymer electrical properties in the THz-frequency range. Importantly, they demonstrate that the complex conductivity analysis is a very efficient, macroscopic and non-destructive (contrary to TEM) tool for the characterization of the dispersion of a graphene nanofiller within a copolyester matrix.

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Section: Dielectric Constantsupporting

confidence: 94%

“…Clearly, adding 1 wt% of graphene flakes to a copolymer matrix measurably increased (~10%) the n of the resultant nanocomposite. Similar results were obtained by other groups [21,22].…”

Section: Index Of Refraction and Absorption Coefficientsupporting

confidence: 91%

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Terahertz Time-Domain Spectroscopy of Graphene Nanoflakes Embedded in Polymer Matrix

et al. 2019

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“…[197] Skalsky et al [198] used few-layer graphene prepared by liquid phase exfoliation from graphite mixed in various concentrations with teflon pellets and characterized the composite by THz spectroscopy. [197] Skalsky et al [198] used few-layer graphene prepared by liquid phase exfoliation from graphite mixed in various concentrations with teflon pellets and characterized the composite by THz spectroscopy.…”

Section: Thz Properties Of Graphenementioning

confidence: 99%

Terahertz Spectroscopy of Nanomaterials: a Close Look at Charge‐Carrier Transport

Kužel

Němec

2019

Advanced Optical Materials

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Transport of charges is a fundamental process in many high-tech applications including photovoltaic or optoelectronic devices, but also in more ordinary components such as unsophisticated wires and other circuitry. The development of nanotechnologies resulted in the fabrication of highly complex materials consisting of a large variety of nanosized elements, which inevitably involve a multitude of charge transport processes occurring on various time-and length-scales. Figure 1 summarizes the most common nanoelements with high application potential.For example, the electrodes employed in Grätzel solar cells [1] are composed of percolated networks of a huge number of metal oxide nanoparticles (top-left panel in Figure 1). Colloidal nanocrystals form the basis for thin film electronics and flexible electronic devices. [2] The synthetic approaches control their composition, size and electronic structure (energy levels, density of states within the bands and in the bandgap) and the charge-carrier transport. [2,3] Nanowires and nanotubes made of conventional semiconductors are quasi 1D systems combining Terahertz spectroscopy has been used for almost two decades for investigations of nanomaterials, including nanocrystals, nanoparticles, nanowires, nanotubes or 2D crystals. Its great importance stems from the fact that it is a noncontact method and, owing to its high frequency and broadband character, it is capable of characterizing charge transport properties within individual nano-objects but also among them. In addition, probing of photoinitiated ultrafast charge dynamics is possible thanks to the sub-picosecond time resolution. Despite this unprecedented potential, the interpretation of the measured terahertz conductivity spectra in many materials is still intensively debated. Herein is presented a review of the experiments performed on nanostructures of conventional semiconductors and on carbon nanomaterials (graphene and carbon nanotubes) during the past decade. The state of the art of the theoretical formalism is provided and discussed, including the intrinsic response, as well as the role of inherent heterogeneity and of the experimental conditions.

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“…Memiliki daya anti bakteri yang tahan lama, dimana semakin kecil ukuran partikel maka pengaruh gaya gravitasi semakin dapat diabaikan. Lain hal nya dengan peningkatan muatan dan kimia permukaan memungkinkan adanya gaya tolak menolak antar partikel dapat terdispersi di dalam air (208)(209)(210) .…”

Section: Daya Hanyutunclassified

SILVER SULFATE (Ag2SO4): MOLECULAR ANALYSIS AND ION TRANSPORT

Yurmaniati¹,

Zainul²

2018

Preprint

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Abstrak Perak sulfat merupakan garam anorganik dengan rumus Ag2SO4. Perak sulfat ini termasuk dalam senyawa ionic karena terdapat ikatan antara logam perak dengan spesi non logam sulfat. Perak sulfat memiliki. berat molekul yaitu 311,799 gr/mol dengan tampilan kristal tidak berwarna dan tidak mudah terbakar. Senyawa ini digunakan dalam penyepuhan perak (silver plating) dan pengganti tanpa noda untuk perak nitrat. Perak Sulfat mengalami interaksi molekul dalam pelarut Air. Tujuan penelitian ini adalah untuk mengetahui karakteristik molekul dan transpor ion Perak Sulfat. Metode yang digunakan dalam penelitian ini adalah penelusuran literatur dengan Endnote X7, pemodelan komputasi, dan perhitungan matematis. Data transpor ion Perak Sulfat yaitu dengan parameter konduktivitas, viskositas, mobilitas ion, dan daya hanyut menggunakan data hasil review beberapa jurnal penelitian yang berkaitan dengan Perak Sulfat sesuai tahapan pada fishbone. Secara termokimia, perak sulfat memiliki entalpi pembentukan standar, ΔfHo 298 -715 kJ/mol dan entropi molar standar, So298 16,74 kJ/mol. Kelarutan Perak Sulfat dalam air yaitu 0,79 gr/100 mL (20 o C) dan dapat larut juga dalam pelarut asam nitrat. Hasil penelitian konduktivitas larutan Ag2SO4 semakin meningkat seiring dengan kenaikan konsentrasi persen massa sesuai grafik hasil perhitungan. Energi optimasi MM2 Minimization, Optimasi MM2 Dynamics, dan Optimasi MM2 Properties berturut-turut yaitu 210. 2194 kcal/mol, 755. 377 kcal/mol, 216. 774 kcal/mol. Kecepatan hanyut molekul perak sulfat dengan potensial Ag2SO4 3,61 V dan jarak antara elektroda 1,5 cm yaitu 2, 407 V/cm. Kata kunci : Perak Sulfat, Interaksi molekul, Pemodelan I. IntroductionPerak sulfat (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) merupakan senyawa ion dari perak dengan rumus Ag2SO4, yang digunakan dalam penyepuhan perak (silver plating) dan pengganti tanpa noda untuk perak nitrat. Garam sulfat ini stabil di bawah kondisi penggunaan dan penyimpanan biasa, meskipun ia menjadi gelap pada pajanan terhadap udara atau cahaya. Perak Sulfat (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) mengalami interaksi molekul dalam pelarut Air. Berat molekul senyawa ini yaitu 311,799 gr/mol dengan tampilan kristal tidak berwarna. Kelarutannya dalam air 0,79 gr/100 mL (20 o C) dan dapat larut juga dalam pelarut asam nitrat. Secara termokimia, perak sulfat (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) memiliki entalpi pembentukan standar, ΔfHo298 -715 kJ/mol dan entropi molar standar, So298 16,74 kJ/mol. Perak sulfat (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) tidak mudah terbakar.Perak Sulfat (Ag2SO4) (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) memiliki konduktivitas (1)(2)(3)(4)(5)(6)(7)(8)(9)(10) . Besarnya nilai konduktivitas (1-10) ditentukan oleh konsentrasi elektrolit. Muatan dalam senyawa dapat dibawa dalam bentuk electron seperti logam atau biasanya digunakan ion positif dan ion negative seperti dalam larutan elektrolit dan leburan garam. Aliran listrik dapat ditemukan dalam suatu larutan karena terdapat di ...

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Terahertz time-domain spectroscopy as a novel metrology tool for liquid-phase exfoliated few-layer graphene

Cited by 14 publications

References 72 publications

Terahertz Time-Domain Spectroscopy of Graphene Nanoflakes Embedded in Polymer Matrix

Terahertz Time-Domain Spectroscopy of Graphene Nanoflakes Embedded in Polymer Matrix

Terahertz Spectroscopy of Nanomaterials: a Close Look at Charge‐Carrier Transport

SILVER SULFATE (Ag2SO4): MOLECULAR ANALYSIS AND ION TRANSPORT

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