Quantitative Analysis of Powdery Sample by Diffuse Reflectance Infrared Fourier Transform Spectrometry: Determination of the <i>α</i>-Component in Silicon Nitride

Tsuge, Akira; Uwamino, Yoshinori; Ishizuka, T.; Suzuki, Keiji

doi:10.1366/0003702914335913

Cited by 30 publications

(31 citation statements)

References 10 publications

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“…The mesoporous silica and mesoporous silicon oxynitride are X-ray amorphous, thus limiting structural characterization; however, the nature of these amorphous networks can be assessed from infrared (IR) spectroscopy studies [9,10], which can provide some information about surface species as well as bulk. There are several IR-active surface species such as silanol groups ("Si(OH)), amide ("Si(NH 2 )), and imides (or silazane) ("Si-NH-Si").…”

Section: Resultsmentioning

confidence: 99%

Synthesis and characterization of non-crystalline mesoporous silicon oxynitride MCM-41 with high nitrogen content

Zhang

Liu

Zheng

2005

Journal of Non-Crystalline Solids

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Section: Resultsmentioning

confidence: 99%

Synthesis and characterization of non-crystalline mesoporous silicon oxynitride MCM-41 with high nitrogen content

Zhang

Liu

Zheng

2005

Journal of Non-Crystalline Solids

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“…In the technique known as diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), it is only valid for small concentrations of analyte where light scattering is limited. 38,39 Prior studies on light extinction in powders for DRIFTS applications have focused on resolving the deviations between reflectance measurements and concentration, which increase with larger absorption and nonconstant scattering. [16][17][18][19]39 In particular, determining deviations for strongly scattering samples necessitates an ability to measure the amount of light scattering.…”

Section: Introductionmentioning

confidence: 99%

Mid-Infrared Scattering in γ-Al₂O₃Catalytic Powders

et al. 2021

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The energy efficiency of heterogeneous catalytic processes may be improved by using mid-infrared light to excite gas-phase reactants during the reaction, since vibrational excitation of molecules has been shown to increase their reactivity at the gas-catalyst interface. A primary challenge for such light-enabled catalysis is the need to ensure close coupling between light-excited molecules and the catalyst throughout the reactor. Thus, it is imperative to understand how to couple infrared light efficiently to molecules near and inside catalytic material. Heterogenous catalysts are often nanoscale metal particles supported on high surface area, porous oxide materials and exhibit feature sizes across multiple scattering regimes with respect to the mid-infrared wavelength. These complex powders make a direct measurement of the scattering properties challenging. Here, we demonstrate that a combination of directional hemispherical measurements along with the in-line transmission measurement allow for a direct measurement of the scattered light signal. We implement this technique to study the scattering behavior of the catalytic support material Î³-Al2O3 (with and without metal loading) between 1040 and 1220 cm-1. We first study how both the mean grain size affects the scattering behavior by comparing three different mean grain sizes spanning three orders of magnitude (2, 40, and 900 Î¼m). Furthermore, we study how the addition of metal catalyst nanoparticles, Ru or Cu, to the support material impacts the light scattering behavior of the powder. We find that the 40 Î¼m grain size scatters the most (up to 97% at 1220 cm-1) and that the addition of metal nanoparticles narrows the scattering angle but does not decrease the scattering efficiency. The strong scattering of the 40 Î¼m grains make them the most ideal support material of those studied for the given spectrum because of their ability to distribute light within the reactor. Lastly, we estimate that less than 100 mW of laser power is needed to cause significant excitation for testing mid-infrared catalysis in a Harrick Praying MantisTMï diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) reactor, a magnitude easily available using commercial mid-infrared lasers. Our work also provides a mid-infrared foundation for a wide range of studies of light-enabled catalysis and can be extended to other wavelengths of light or to study the scattering behavior of other complex powders in other fields, including ceramics, biomaterials, and geology.

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“…Experimental energy gaps of QDs are often determined from diffuse reflectance spectroscopy, using the Kubelka− Munk remission function which converts reflectance to absorption edge measurements. 36,37 The nature of electronic transitions is typically deduced from the Tauc equation fits into reflectance data. 8 The energy gaps obtained in these measurements usually follow expected trends.…”

Section: ■ Introductionmentioning

confidence: 99%

Optical Transitions and Excitonic Properties of Ge_1–xSn_x Alloy Quantum Dots

et al. 2017

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Using hybrid functional calculations and experimental characterization, we analyze optical properties of 2–3 nm Ge1–x Sn x alloy quantum dots, synthesized by colloidal chemistry methods. Hybrid functional theory, tuned to yield experimental bulk band structure of germanium, reproduces directly measured properties of Ge1–x Sn x quantum dots, such as lattice constants, energy gaps, and absorption spectra. Time-dependent hybrid functional calculations yield optical absorption in good agreement with experiments, and allow probing the nature of the dark excitons in quantum dots. Calculations suggest a spin-forbidden dark exciton ground state, which is supported by the changes in the photoluminescence lifetimes with temperature and tin concentrations. The synthesis and theoretical understanding of Ge1–x Sn x alloy quantum dots will add to the overall toolbox of low to nontoxic, silicon-compatible group IV semiconductors with potential application in visible to near-infrared optoelectronics.

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Quantitative Analysis of Powdery Sample by Diffuse Reflectance Infrared Fourier Transform Spectrometry: Determination of the α-Component in Silicon Nitride

Cited by 30 publications

References 10 publications

Synthesis and characterization of non-crystalline mesoporous silicon oxynitride MCM-41 with high nitrogen content

Synthesis and characterization of non-crystalline mesoporous silicon oxynitride MCM-41 with high nitrogen content

Mid-Infrared Scattering in γ-Al₂O₃Catalytic Powders

Optical Transitions and Excitonic Properties of Ge_1–xSn_x Alloy Quantum Dots

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Quantitative Analysis of Powdery Sample by Diffuse Reflectance Infrared Fourier Transform Spectrometry: Determination of the α-Component in Silicon Nitride

Cited by 30 publications

References 10 publications

Synthesis and characterization of non-crystalline mesoporous silicon oxynitride MCM-41 with high nitrogen content

Synthesis and characterization of non-crystalline mesoporous silicon oxynitride MCM-41 with high nitrogen content

Mid-Infrared Scattering in γ-Al2O3Catalytic Powders

Optical Transitions and Excitonic Properties of Ge1–xSnx Alloy Quantum Dots

Contact Info

Product

Resources

About

Mid-Infrared Scattering in γ-Al₂O₃Catalytic Powders

Optical Transitions and Excitonic Properties of Ge_1–xSn_x Alloy Quantum Dots