Synthesis, crystal structure, vibrational study, optical properties and Hirshfeld surface analysis of a new centrosymmetric hybrid material, bis(3-aminoquinolium) tetrachloridocobaltate (II)

Background: The title compound (C9H9N2)2[CoCl4] belongs to a large compound’s family, enriching the new technologies materials range. Objective: The chemical synthesis and the crystal structure are the main goals to reach in this study. In addition, the optoelectronic properties and the material behavior are investigated. Methods: The single-crystal diffraction, photoluminescence, infrared spectroscopy, and several computations are applied in this work to characterize the studied compound. Results: At room temperature, the synthesized (C9H9N2)2[CoCl4] crystallizes in the monoclinic C2/c space group. The cohesion of the 0-D crystal structure is ensured by hydrogen interactions and confirmed by the Hirshfeld surface analysis. Conclusion: A new hybrid compound is discovered and added to the structural database ICDD. The structural study, the spectroscopic investigations, particularly the photoluminescence, indicate that the newly obtained material is promising for interesting application as a non-linear optical material.

Cholesterol decorated pyridinium urea and carbamate as π-gelators for selective recognition of F- ions

Aim: Design and synthesis of new molecules capable of forming self-assembled gels are indispensable to harvest new functional materials. Supramolecular gels have potential in many areas particularly in biology and materials chemistry. Of the different types of applications, visual sensing of biologically relevant ionic analytes is a fairly recent trend. Here we describe naked eye detection of fluoride ions involving sol-gel methodology. Methods: To execute this, cholesterol substituted pyridinium salts 1-4 have been designed and synthesized of which compounds 3 and 4 served as potential gelators for the naked eye detection of F- ions in DMSO and DMSO-H2O (1:1, v/v) respectively. Results: Gelation study reveals that not only the aromatic surface is crucial for the self-aggregation of molecules via π-π stacking interactions, but also polarity, rigidity and conformational flexibility of the molecules that govern the intermolecular association of gelators are important. Conclusion: Moreover, incorporation of fluorophores (naphthalene) as aromatic surface in the molecular designs, promotes the gelator molecules to execute sensing behavior for F- with high degree of sensitivity in solution phase also.

A Review of Synthesis and Applications of Boron Nitride Nanotubes (BNNTs) with Future Prospects

: Emerging nanotechnology in the early 1990s introduced nanoscaled and advanced materials such as Carbon Nanotubes (CNT) with specific chemical structures and exceptionally unique properties. Among various nanostructures, particularly nanotubes have shown their specific values due to their inherent characteristics. With time, new vistas were opened for developing other nanotube-based materials due to their remarked mechanical strength and versatile applications. In recent decades, BNNTs with promising applicability have been synthesized via several methods. This review highlights the synthetic strategies of Boron Nitride Nanotubes (BNNTs) with their potential applications in various applied sectors, including energy, electronics, and biomedical applications.

Simulating Ultrasound Piezoelectric Power Transfer in the Near Field and Experimental Validations

Background: Acoustic power transfer is a method for wireless energy transfer to implanted medical devices that permits a greater range of separation between transmitter and receiver than is possible with inductive power transfer. In some cases, short-distance ultrasonic power transfer may be employed; consequently, their operation may be complicated by the near-field aspects of piezoelectric acoustic energy transfer. Methods: A piezoelectric energy transfer system consisting of two lead zirconate titanate (PZT) transducers was analyzed in this work using a combination of experimental measurements and computer simulations. Results: Simulations using the COMSOL Software package showed good agreement with a measured output voltage as a function of the distance between and alignment of the transmitter and receiver with water as a medium. We also simulated how operating frequency affects power transfer efficiency at various distances between the transmitter and receiver and found reasonable agreement with experiments. We report model predictions for power transfer efficiency as a function of the thickness and diameter of the transmitter and receiver. Conclusion: The results show that with proper choice of parameters, piezoelectric systems can provide high power transfer efficiency in the near-field region.

Microstructure evolution of yttria compacts by powder technology

Background: Innovation in ceramic materials relies on processing of powders. Yttria also known as yttrium oxide belongs to rare earths group, which usual form is RE2O3 (RE from La to Lu, including Sc and Y). Due to great end use of RE based materials since agriculture until astronomy, the main economies such as United States of America and European Union addressed REs as critical materials. The aim of this paper is to obtain dense compacts of yttria by powder technology, in which the effect of sintering temperature on samples microstructure is evaluated. Methods: Yttria powders (Y2O3) were used as starting material, being characterized by Photon Correlation Spectroscopy (PCS); X-ray Diffraction (XRD); Scanning Electron Microscopy (SEM). Powder compacts in cylindrical shape formed by uniaxial compaction, followed by hydrostatic compaction were evaluated by means of apparent density. Sintered samples under sintering temperatures from 1350 to 1550ºC were evaluated by SEM, XRD, apparent density, and true density. Results: Cubic C-type yttria powders exhibited mean particle size (d50) of 1.6μm, and morphology like acicular. Powder compacts (diameter x height) of 9.57mm ± 0.01 x 1.53mm ± 0.01 presented mean apparent density of 53.69% (based on free powder density). As sintered samples at 1550ºC, exhibited the most densification 65.0% related to green density and 91.0% related to theoretical density, respectively. Conclusion : Yttria cylindrical compacts with dense microstructure and symmetric dimensions were formed by powder technology from powders with mean particle size of 6.51μm, by compaction methods (uniaxial and hydrostatic), followed by sintering. The most densification of samples was achieved by the sintering condition of 1550ºC for 2h, providing samples with theoretical density of 91%. These results provide useful subsidies to advance toward full densification of ytrria based materials.

Growth Process of Cd0.8Zn0.2Te Crystal to Enhance its Performance as Detector for High-energy Radiation

Introduction: In the applications of room temperature detector for high-energy radiation, there are two critical requirements for the semiconducting material cadmium zinc telluride (CdZnTe): (1) high electrical resistivity to reduce the bulk leakage current and (2) low levels of structural defects which hinder the detectivity as trapping and recombination centers for the carriers. To enhance the performance of the detectors, an optimal single process has been developed in the melt growth of Cd0.8Zn0.2Te by directional solidification with controlled Cd overpressure to maximize the electrical resistivity as well as minimize the structural defects, including Te precipitates/inclusions of the grown CdZnTe crystals. Method: Using the phase diagram data of pressure-temperature-composition (P-T-X), melt growth of Cd0.8Zn0.2Te crystals by directional solidification from a starting melt at 1145oC has been performed with various Cd overpressures controlled by the temperature of a Cd reservoir. The grown crystals were sliced and were characterized by electrical resistivity measurements and chemical analysis of Glow Discharge Mass Spectroscopy (GDMS). The structural defects were studied by the infrared (IR) transmission images taken by an IR microscope. Result: By doping of In (4 – 6 ppm, atomic) and growing with a Cd reservoir in the range of 785 to 825oC, the electrical conductivity were consistently higher than 109cm and up to 2x1011cm. From the trend of the Te precipitates density observed by the IR micrographs, it was concluded that a Cd reservoir temperature of 820+10oC resulted in the lowest precipitate density. Conclusion: The employment of a Cd reservoir temperature of 820+5 oC during the growth process will provide the optimal Cd pressure over the melt at 1145oC to maximize the electrical resistivity as well as minimize the structural defects, including Te precipitates/inclusions of the grown Cd0.8Zn0.2Te crystals. Discussion: Since the solids of different compositions, x in the Cd1-xZnxTe system, have different liquidus/solidus temperatures as well as different homogeneity ranges, the procedure presented here for the Cd0.8Zn0.2Te solid may not applicable to other compositions.