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Microwave synthesis of Zn:Mn:PbI2 micro-size nanosheets and their characterizations

Shkir Mohd., Al-Kotb M. S., Yahia I. S., Alshahrani T., AlFaify S., Abutalib M. M.

Materials Science Poland

2020

Vol. 38, No. 2

367--373

Herein, we are reporting, for the first time, a microwave-assisted synthesis of lead iodide (PbI2) nanosheets (NSs) with codoping of Zn and Mn, confirmed by SEM/EDX. In the co-doping Mn concentration was kept at a constant level (i.e. 15 %) while Zn concentration was varied from 1 wt.% to 10 wt.%. The morphological analysis confirming presence of the dopant was done through SEM/EDX. The single phase and polytypic nature of NSs were established by XRD and FT-Raman examinations. Homogeneous doping of Mn and Zn in prepared PbI2 NSs was confirmed by SEM mapping analysis. The dielectric and electrical properties were measured by preparing a compact pellet of NSs at 49820 Pa pressure. The dielectric constant and electrical conductivity were enhanced by Zn:Mn co-doping in PbI2. The radiation activity was tested by cesium-137 (137Cs) radioactive source and its increase resulting from the doping was observed. The enhanced properties suggest that the prepared NSs may be useful in electro-optic and radiation detection device applications.

Detailed spectral monitoring of different combustible blends based on gasoline, ethanol and methanol using FT-Raman spectroscopy

Ortega Clavero V., Weber A., Schröder W., Meyrueis P., Javahiraly N.

Environmental Biotechnology

2012

Vol. 8, No. 1

1-6

The use of mixtures of oil-based fuels with organic chemical components (e.g. ethanol, methanol) has been gaining ground in recent years. Several countries try nowadays to replace part of the fossil fuels for various reasons including economics, sustainability or optimization of resources. The characteristics of these combustiblerelated chemical component blends can be analyzed by different means. Optical spectral analysis (e.g. Raman, Fourier-transforminfrared, etc.) can extract inmany casesmost of the required information concerning themolecular structure of a determined chemical sample in an effective and clean manner. Experimental detailed Raman spectra fromvarious gasoline-ethanol blends and a gasoline-ethanolmethanol blend are presented. The Raman spectral information obtained has been used for approximated quantitative analysis with no additional chemical marker or complicated calibration methods. The analysis has been performed using a self-designed, low-cost, robust and frequency precise Fourier transform Raman (FT-Raman) spectrometer. This proposed FT-Raman spectrometer has been constructed with a Michelson interferometer, an in-house designed photon counter, and a sensitive trans-impedance photo-detector. Additional complex hardware was not used to compensate the mechanical or thermal drifts disturbances in the interferometer. For accurate spectral calculation an interference pattern generated by a low-power Helium-Neon laser (wavelength λ=632.816nm)was used. The resulting spectral data are in the range of 0*cm-1 to 3500*cm-1. The resolution of these Raman spectra is 1.66*cm-1. Higher resolutions are possible since the scanning distances in the Michelson interferometer can be extended substantially before instrumental effects appear. A comparison of the experimental results obtained with standard Raman shift values revealed a satisfactory accuracy and precision in frequency detection.

Vibrational Spectra, Phase Transition and Nonlinear Optical Properties of Anilinium Perchlorate Molecular-Ionic Solid

Marchewka M., Debrus S., Drozd M., Baran J., Barnes A. J., Xue D., Ratajczak H.

Polish Journal of Chemistry

2003

Vol. 77 / nr 11

1625-1636

Crystals of anilinium perchlorate, C6H5NH ClO 3 4 + , were obtained by slow evaporation of an aqueous solution at room temperature. Powder Kurtz-Perry measurements were performed for the title material. The efficiency of second harmonic generation was estimated relative to KDP: d = 0.21dKDP. Room temperature powder infrared and Raman measurements for the title solid and its deuterated analogue were carried out. The vibrational spectra in the regions of the internal vibrations of the ions corroborate the X-ray data (reported by Paixao et al. [1]). Differential scanning measurements performed on the powder sample indicate a first order phase transition at about 220 K.Apossible mechanism of the phase transition is suggested in relation to disorder of the hydrogen atoms on nitrogen atoms (reported in [1]). The role of the aniline molecule in the second harmonic generation is discussed.