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For the advancement of solvent processing and manufacturing procedures, understanding the rheological characteristics of suspended two-dimensional (2D) materials is crucial. Here, we synthesized MoS 2 nanosheets using a simple, easy and efficient hydrothermal way. Structural and morphological studies have been carried out using X-ray diffraction and scanning/transmission electron microscopy confirming the formation of MoS 2 nanosheets. The elemental composition of the as-prepared samples was studied using an energy-dispersive X-ray analyser. Optical properties were studied using FTIR spectroscopy. MoS 2 nanosheets prepared at 180 °C and 200 °C were considered for rheological studies. For rheological studies, stable dispersions of MoS 2 nanosheets in water were analysed. Initially, water dispersion of MoS 2 nanosheets showed non-Newtonian behaviour following the Newtonian/Bingham plastic fluid model. Its viscoelastic characteristics suggest lubricating fluid application. DFT has been used to study MoS 2 nanosheets under biaxial strain. This simple aqueous method can provide a reliable lubricant and improve MoS 2 nanosheets rheology. [ABSTRACT FROM AUTHOR]

Impedance studies were conducted on spray deposited Cu doped SnO 2 thin films. Rietveld analysis provided evidence of non-existence of any other phase due to doping. Controlled injection of ethanol vapor was done to study the surface activity of these films at different temperatures. The cole–cole plots of ethanol absorbed films to that of unexposed thin films were constructed at different temperatures and compared. The studies reveal that the electron scattering process was homogeneous in nature and the film had a narrow relaxation time. Levenberg–Marquardt algorithm with unweighted function was used for theoretical fitting of the cole–cole plots that revealed the weakening of the Fermi pinning level. [ABSTRACT FROM AUTHOR]

Doped and undoped specimens of nano-particulate ZnO with 0.5 wt% and 1 wt% ruthenium were prepared through a chemical route. Structural characterization of the samples performed with XRD established that all the nanoparticles are of zinc oxide having polycrystalline nature. Morphological studies were conducted using FESEM to confirm the grain size and texture. Electrical measurements showed that the ac conductivity increases with frequency but decreases with increasing ruthenium concentration, making it a potential option for device applications. It is found that the absorbance does not significantly change with doping. The above fact is further confirmed from the bandgap calculations using the reflectance graphs. A decrease of bandgap from 3.42 to 3.19 eV with increasing Ru concentration is observed making it an important and advantageous material for potential visible light photocatalytic applications involving metal oxide nanostructures. [ABSTRACT FROM AUTHOR]

Pure and Cu-doped zinc oxide (ZnO) nanoparticles were prepared using a chemical method. The dopant concentration (Cu/Zn in atomic percentage (wt%)) is varied from 0 to 3 wt%. Structural characterization of the samples performed using X-ray diffraction (XRD) confirmed that all the nanoparticles of zinc oxide are having polycrystalline nature. Morphological studies were conducted using field emission scanning electron microscopy (FESEM) to confirm the grain size and texture. Electrical measurements showed that the AC conductivity initially decreases and then rises with increasing Cu concentration. The UV-Vis studies showed absorbance peaks in the 200-800 nm region. It is found that the absorbance does not significantly change with doping. This fact is further confirmed from the band-gap calculations using the reflectance graphs. When analysed in terms of Burstein-Moss shift, an increase of band gap from 3.42 to 3.54 eV with increasing Cu concentration is observed. In the Photoluminescence (PL) studies a red-shift is observed with increasing dopant concentration. [ABSTRACT FROM AUTHOR]

Abstract: Nanocrystalline SnO2 was prepared by the co-precipitation method and doped with CuO. Crystallite sizes were estimated by Scherrer formula to be of the order of 90nm and lesser. A.C. conduction behaviour of the samples has been described by the different hopping processes. From impedance analysis multi-relaxation processes in the samples are evident. Shrinkage of Cole–Cole plots with increase in temperature is also observed in our case which shows role of grain and grain boundary effects in the conduction mechanism with rise in temperature. Dielectric constant decreases with frequency but increases with rise in temperature which is governed by different components of polarizability (deformational and relaxational polarization). Dielectric constant increases with rise in temperature but at higher frequency range it takes constant value. Impedance analysis is used to explain the effects of grain and grain boundary on transport mechanism of undoped and CuO modified SnO2 nanoparticles. [Copyright &y& Elsevier]