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Raman crystallinity

Sze Shin Low, Hwei-San Loh, Jian Sheng Boey, Poi Sim Khiew, Wee Siong Chiu, Michelle T T Tan
An efficient electrochemical impedance genosensing platform has been constructed based on graphene/zinc oxide nanocomposite produced via a facile and green approach. Highly pristine graphene was synthesised from graphite through liquid phase sonication and then mixed with zinc acetate hexahydrate for the synthesis of graphene/zinc oxide nanocomposite by solvothermal growth. The as-synthesised graphene/zinc oxide nanocomposite was characterised with scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and X-ray diffractometry (XRD) to evaluate its morphology, crystallinity, composition and purity...
February 27, 2017: Biosensors & Bioelectronics
Emanuela Filippo, Francesca Baldassarre, Marco Tepore, Maria Rachele Guascito, Daniela Chirizzi, Antonio Tepore
The growth of MoO<sub>3</sub> hierarchical plates was obtained by direct resistive heating of molybdenum foil at ambient pressure in absence of any catalysts and templates. Plates synthesized after 60 min resistive heating typically growth in an single-crystalline orthorhombic structure that develop preferentially in [001] direction, as characterized by HRTEM, SAD and Raman-scattering measurements. They are about 100-200nm in thickness and a few tens micrometers in length. As heating time proceeds to 80 min, plates of α-MoO<sub>3</sub> form a branched structure...
March 20, 2017: Nanotechnology
L Khomenkova, D Lehninger, O Kondratenko, S Ponomaryov, O Gudymenko, Z Tsybrii, V Yukhymchuk, V Kladko, J von Borany, J Heitmann
Ge-rich ZrO2 films, fabricated by confocal RF magnetron sputtering of pure Ge and ZrO2 targets in Ar plasma, were studied by multi-angle laser ellipsometry, Raman scattering, Auger electron spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction for varied deposition conditions and annealing treatments. It was found that as-deposited films are homogeneous for all Ge contents, thermal treatment stimulated a phase separation and a formation of crystalline Ge and ZrO2. The "start point" of this process is in the range of 640-700 °C depending on the Ge content...
December 2017: Nanoscale Research Letters
Michael T Ruggiero, J Axel Zeitler, Alessandro Erba
The intermolecular anharmonic potential of crystalline purine is probed by means of temperature-dependent terahertz time-domain spectroscopy, low-frequency Raman scattering, X-ray diffraction, and ab initio quasi-harmonic quantum-chemical simulations. As temperature increases, anharmonicity in the intermolecular interactions results in strongly anisotropic thermal expansion - with a negative thermal expansion along the b crystallographic axis - yielding corresponding bulk structural modifications. The observed thermally-induced shifts of most vibrational bands in the terahertz region of the spectra are shown to arise from volume-dependent thermal changes of the hydrogen-bond pattern along the a and b crystallographic axes...
March 17, 2017: Chemical Communications: Chem Comm
Ruoqi Ai, Xun Guan, Jia Li, Kangkang Yao, Peng Chen, Zhengwei Zhang, Xidong Duan, Xiangfeng Duan
Two-dimensional layered materials (2DLMs) have attracted considerable recent interest for their layer-number-dependent physical and chemical properties, as well as potential technological opportunities. Here we report the synthesis of two-dimensional layered cadmium iodide (CdI2) nanoplates using a vapor transport and deposition approach. Optical microscopy and scanning electron microscopy studies show that the resulting CdI2 nanoplates predominantly adopt hexagonal and triangular morphologies with a lateral dimension of ∼2-10 μm...
March 17, 2017: ACS Nano
Aurea Bernardino-Nicanor, Gerardo Acosta-García, Norma Güemes-Vera, José Luis Montañez-Soto, María de Los Ángeles Vivar-Vera, Leopoldo González-Cruz
Starches isolated from four ayocote bean varieties were modified by thermal treatment to determinate the effect of the treatment on the structural changes of ayocote bean starch. Scanning electron microscopy indicates that the starch granules have oval and round shapes, with heterogeneous sizes and fractures when the extraction method is used. The presence of new bands at 2850 and 1560 cm(-1) in the FT-IR spectra showed that the thermal treatment of ayocote beans induced an interaction between the protein or lipid and the amylose or amylopectin, while the sharpest band at 3400 cm(-1) indicated a dehydration process in the starch granule in addition to the presence of the band at 1260 cm(-1), indicating the product of the retrogradation process...
March 2017: Journal of Food Science and Technology
Shahanavaj Khan, Anees A Ansari, Azmat Ali Khan, Maha Abdulla, Omar Al-Obaid, Rehan Ahmad
Copper oxide nanoparticles (CuO-NPs) were synthesized using a urea-based thermal decomposition technique, and characterized using different techniques. X-ray diffraction (XRD) and Raman spectroscopy confirmed the phase purity and crystalline structure of CuO-NPs. The size of CuO-NPs was investigated using XRD and was confirmed via dynamic light scattering analysis. CuO-NPs showed an average diameter of ∼20nm. The possible cytotoxicity of CuO-NPs was evaluated in HT-29 and SW620 cancer cell lines. The median inhibitory concentration of CuO-NPs in HT-29 and SW-620 cells was 4...
March 6, 2017: Colloids and Surfaces. B, Biointerfaces
Yaxin Guo, Jie Wei, Yalong Liu, Tiantian Yang, Zhuo Xu
Cu2ZnSnS4 (CZTS) hierarchical microstructures were synthesized by using a facile and nontoxic hydrothermal route, which were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM), Raman spectra, and UV-Vis absorption spectra. The results and analysis show that surfactants used in the hydrothermal process have significant effect on the phase structures, morphologies, and photocatalytic activities of CZTS powders. Especially, the well-crystallized and pure kesterite CZTS hierarchical microstructures were synthesized with the addition of high-concentration tartaric acid (TA) in the hydrothermal process...
December 2017: Nanoscale Research Letters
Wilson Kong, Cihan Bacaksiz, Bin Chen, Kedi Wu, Mark Blei, Xi Fan, Yuxia Shen, Hasan Sahin, David Wright, Deepa S Narang, Sefaattin Tongay
Layered transition metal trichalcogenides (TMTCs) are a new class of anisotropic two-dimensional materials that exhibit quasi-1D behavior. This property stems from their unique highly anisotropic crystal structure where vastly different material properties can be attained from different crystal directions. Here, we employ density functional theory predictions, atomic force microscopy, and angle-resolved Raman spectroscopy to investigate their fundamental vibrational properties which differ significantly from other 2D systems and to establish a method in identifying anisotropy direction of different types of TMTCs...
March 10, 2017: Nanoscale
Yaxing Wang, Yumin Wang, Linjuan Zhang, Lanhua Chen, Zhiyong Liu, Xuemiao Yin, Daopeng Sheng, Juan Diwu, Jianqiang Wang, Ning Liu, Zhifang Chai, Shuao Wang
As the crucial soluble species of long-lived radionuclides (129)I and (79)Se, iodate and selenite anions commonly share similar geometry of the trigonal pyramid XO3 (X = I, Se) but in different valence states. Although large amounts of investigations have been performed aiming at understanding the environmental behavior of these two anions individually, studies on cases when they coexist are extremely scarce. Structurally well-characterized natural/synthetic crystalline solids simultaneously incorporating these two anions as potential solubility-limiting products at the nuclear waste geological depository remain elusive...
March 9, 2017: Inorganic Chemistry
Sungho Lee, Kyosuke Ueda, Takayuki Narushima, Takayoshi Nakano, Toshihiro Kasuga
BACKGROUND: Niobia/magnesia-containing orthophosphate invert glasses were successfully prepared in our earlier work. Orthophosphate groups in the glasses were cross-linked by tetrahedral niobia (NbO4) and magnesia. OBJECTIVE: The aim of this work is to prepare calcium orthophosphate invert glasses containing magnesia and niobia, incorporating silica, and to evaluate their structures and releasing behaviors. METHOD: The glasses were prepared by melt-quenching, and their structures and ion-releasing behaviors were evaluated...
2017: Bio-medical Materials and Engineering
Ganesh Venkatachalam, S V Sheen Mers, Shivakumar Umadevi
In this work, two different types of gold nanostars (Au NS) namely short-spiked nanostars (SSNS) and long-spiked nanostars (LSNS) are prepared by using hexagonal lyotropic liquid crystalline (LLC) phase as a template. Basically the formation, size and length of spikes or arms of the resultant Au NS are controlled by preparation either in a hexagonal LLC phase or in an isotropic phase. These NS are anchored onto ITO electrodes through self-assembled monolayer (SAM) of 3-mercaptopropyltrimethoxysilane (MPTMS) acting as a linker molecule...
March 7, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Mirjana Dimitrievska, Federica Boero, Alexander P Litvinchuk, Simona Delsante, Gabriella Borzone, Alejandro Perez-Rodriguez, Victor Izquierdo-Roca
This work presents a comprehensive analysis of the structural and vibrational properties of the kesterite Cu2ZnSnS4 (CZTS, I4̅ space group) as well as its polymorphs with the space groups P4̅2c and P4̅2m, from both experimental and theoretical point of views. Multiwavelength Raman scattering measurements performed on bulk CZTS polycrystalline samples were utilized to experimentally determine properties of the most intense Raman modes expected in these crystalline structures according to group theory analysis...
March 6, 2017: Inorganic Chemistry
Matteo Savastano, Carla Bazzicalupi, Celeste García, Cristina Gellini, María Dolores López de la Torre, Palma Mariani, Fabio Pichierri, Antonio Bianchi, Manuel Melguizo
Protonated forms of the tetrazine ligand L2 (3,6-bis(morpholin-4-ylethyl)-1,2,4,5-tetrazine) interact with iodide in aqueous solution forming relatively stable complexes (ΔG° = -11.6(4) kJ mol(-1) for HL2(+) + I(-) = (HL2)I and ΔG° = -13.4(2) kJ mol(-1) for H2L2(2+) + I(-) = [(H2L2)I](+)). When solutions of [(H2L2)I](+) are left in contact with air, crystals of the oxidation product (H2L2)2(I3)3I·4H2O are formed. Unfortunately, the low solubility of I3(-) complexes prevents the determination of their stability constants...
March 6, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Songming Wan, Guimei Zheng, Yanan Yao, Bo Zhang, Xiaodong Qian, Ying Zhao, Zhanggui Hu, Jinglin You
LiB3O5 is the most widely used nonlinear optical crystal. Li2Mo3O10 (a nominal composition) is a typical flux used to produce large-sized and high-quality LiB3O5 crystals. The structure of the LiB3O5-Li2Mo3O10 high-temperature solution is essential to understanding the flux behavior of Li2Mo3O10 but still remains unclear. In this work, high-temperature Raman spectroscopy combined with density functional theory (DFT) was applied to study the LiB3O5-Li2Mo3O10 solution structure. Raman spectra of a LiB3O5-Li4Mo5O17-Li2Mo4O13 polycrystalline mixture were recorded at different temperatures until the mixture melted completely...
March 2, 2017: Inorganic Chemistry
Boris A Kolesov
We present a Raman-spectroscopic study of secondary amides (acetanilide, methacetin, phenacetine, orthorhombic and monoclinic polymorphs of paracetamol) as well as simple amides formanilide and benzanilide. The study was carried out on single crystals and in the temperature range of 5-300K. The series of compounds with the same molecular fragment - acetamide group - can serve as a model system to study the interrelation between this group and the properties of the intermolecular "peptide-type" NH⋯OC hydrogen bonds...
February 24, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Dong Li, Debraj Chandra, Ryouchi Takeuchi, Takanari Togashi, Masato Kurihara, Kenji Saito, Tatsuto Yui, Masayuki Yagi
N2-intercalated crystalline mesoporous tungsten trioxide (WO3) was synthesized by a thermal decomposition technique using dodecylamine (DDA) as a surfactant template with a dual functional role of an N atom source for N2 intercalation, alongside its conventional structure directing role (by micelle formation) to induce a mesoporous structure. N2 physisorption analysis showed that the specific surface area (57.3 m2 g-1) of WO3 (WO3-DDA) templated with DDA is 2.3 times higher than that (24.5 m2 g-1) of WO3 (WO3-bulk) prepared without DDA due to the mesoporous structure of WO3-DDA...
March 1, 2017: Chemistry: a European Journal
Jian Lin, Zhixing Fu, Jiaxu Zhang, Yujia Zhu, Dandan Hu, Dongsheng Li, Tao Wu
A series of electronically active viologen dications (RV) with tunable substituent groups were utilized to hybridize with [Ge4S10](4-) (T2 cluster) to form the hybrids of T2@RV. These hybrids exhibited variable supermolecular assembly formation, tunable optical absorption properties, and different photoelectric response under the influence of different RV dications. Raman testing and time-dependent photocurrent response indicated that the photosensitivity and photostability of T2@RV could be integrated while choosing suitable RV dications...
February 28, 2017: Inorganic Chemistry
Oliver Skibitzki, Ivan Prieto, Roksolana Kozak, Giovanni Capellini, Peter Zaumseil, Yadira Arroyo Rojas Dasilva, Marta D Rossell, Rolf Erni, Hans von Känel, Thomas Schroeder
We present the nanoheteroepitaxial growth of gallium arsenide (GaAs) on nano-patterned silicon (Si) (001) substrates fabricated using a CMOS technology compatible process. The selective growth of GaAs nano-crystals (NCs) was achieved at 570 °C by MOVPE. A detailed structure and defect characterization study of the grown nano-heterostructures was performed using scanning transmission electron microscopy, x-ray diffraction, micro-Raman, and micro-photoluminescence (μ-PL) spectroscopy. The results show single-crystalline, nearly relaxed GaAs NCs on top of slightly, by the SiO2-mask compressively strained Si nano-tips (NTs)...
February 27, 2017: Nanotechnology
Paula M Carmona-Quiroga, Robert M J Jacobs, Sagrario Martínez-Ramírez, Heather A Viles
Extending the use of novel anti-graffiti coatings to built heritage could be of particular interest providing the treatments are efficient enough in facilitating graffiti removal and long-lasting to maintain their protective properties without interfering with the durability of the substrates. However, studies of the durability of these coatings are scarce and have been mainly carried out under accelerated weathering conditions, the most common practice for assessing the durability of materials but one that does not reproduce accurately natural working conditions...
2017: PloS One
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