Observation of Dominant Nuclei and Magic-Sized CdS Nanoparticles in a Single-Phase System

Cadmium sulfide nanoparticles (CdS NPs) were synthesized by using cadmium acetate and thiourea as precursors and sodium oleate as the surfactant under different cadmium acetate concentrations in anhydrous ethanol. Cadmium (Cd) precursor concentration greatly affected the nucleation-growth of CdS NPs. In extremely dilute solution with a Cd precursor concentration of 0.1 mmol · L−1, an overlapped nucleation and growth corresponding to two pronounced absorption peaks at 310 nm and 350 nm, respectively, was observed. Unparalleled nucleation was dominant within very long reaction time until 10 hours. The nuclei and the resulting magic-sized CdS NPs may be used as seeds to prepare size and shape controllable nanoparticles. On the contrary, at a high Cd precursor concentration (5 mmol · L−1), nucleation and growth were separated. Only one first exciton absorption peak standing for the growth of regular CdS NPs appeared at 440 nm. Many techniques including transmission electron microscopy (TEM), X-ray powder diffraction (XRD), ultraviolet-visible (UV-Vis) absorption and photoluminescence (PL) spectrometers were applied to characterize the morphology, crystalline structure, and optical properties of CdS NPs.

An Efficient Nonlinear Optical, Magnetic Transition Metal Ion Nickel Doped L- Threonine Cadmium Acetate Monohydrate

The semi organic nonlinear optical single crystal of L- Threonine Cadmium acetate Monohydrate (LTCAM) doped Ni 2+ion is prepared by the technique slow evaporation solution growth. The prepared crystal was analysed by XRD, EDAX, UV-Vis- NIR, IR, TG/DTA, Photo Luminescence (PL), VSM and SHG measurements. The SXRD shows the crystal come under the monoclinic crystal system with P21 noncentrosymmetric space group. In the visible and near infrared region the crystal shows good optical response and it is a thermally stable compound. The band gap of the grown crystal was 5.02ev. The functional groups are confirmed by FTIR analysis. The luminescent behaviour of the doped crystal shows its ability as UV filters. The dopant turns its magnetic property in to semi paramagnetic nature.

Ferroelectric Aspect and Phase Transitions of Solid Solution of Cadmium Acetate with Aluminium (III) Oxide

The behavior of variation of dielectric constant with temperature of solid solution of Cadmium Acetate Cd(C2H3O2)2 with Aluminium (III) Oxide Al2O3 and other dielectric parameters have been measured between the temperatures 35°C to 100°C using the capacitance bridge model ZENITH-FM89A and Q meter at the frequency of 2000 Hz. In the measurement, it have been observed that the compound has lower value of dielectric constant (ε = 1580) below 36ºC, which rises upto a value of 5600 at the moderate temperature of 45ºC. After this temperature, the dielectric constant of compound decreases upto the value of nearly 3521 at the temperature of 75ºC and a high peak at the temperature of 76°C (ε = 7000) in the heating cycle curve with some fluctuations.. When the variation of dielectric constant was studied in cooling cycle the peak was observed at 62ºC(ε = 6500), above and below this temperature dielectric constant decreases with some intermediate fluctuations and by increasing aluminium oxide content in the mother compound, its quality factor also increases with a little effect on dielectric constant. The cooling cycle curve does not follow heating curve because of the relaxor behaviour of the compound. The results have been explained on the basis of crystal structure changes and the possibility of free internal rotation of acetate groups within the crystal lattice at elevated temperature. One of the advantages of Cd(C2H3O2)2 with Al2O3 is that by varying the Aluminium Oxide content, one can control temperature coefficient of resonant frequency τf without affecting the other properties. This is important for many ferroelectric applications because τf of near about low value is not always required. A non-zero τf is often preferable to compensate for frequency variation due to the effect of temperature change on the resonator housing and dielectric support structure. Solid solution of Cadmium Acetate with Aluminium Oxide suggests for its valuable applications as dielectric material with excellent properties useful in ceramics engineering and communication system. KEY WORDS: Polarization, Quality Factor, Dielectric Constant, Phase Transition, Curie temperature, Resonant Frequency and Ceramics Engineering.

Polyaniline/Ag2S–CdS Nanocomposites as Efficient Electrocatalysts for Triiodide Reduction in Dye-Sensitized Solar Cells

In this study, an Ag2S–CdS nanocomposite (AC11) was prepared through chemical co-precipitation of silver nitrate and cadmium acetate in an aqueous solution of thiourea. We then synthesized PACI, a nanocomposite of polyaniline (PANI) and AC11, through in situ polymerization of aniline in an AC11-containing solution, resulting in uniform embedding of the AC11 nanoparticles in the PANI fibers. Moreover, we synthesized the nanocomposite PACO through deposition of the AC11 nanoparticles on the surface of the PANI fibers. PANI, PACI, and PACO were then spin-coated onto conducting glasses to form PANI-S, PACI-S, and PACO-S counter electrodes, respectively, for dye-sensitized solar cells (DSSCs). Cyclic voltammetry revealed that the electrochemical catalytic activity of the PACI-S electrode was much higher than those of the PANI-S and PACO-S electrodes. Furthermore, the photovoltaic properties of the PACI-S-based DSSC were much better than those of the PANI-S- and PACO-S-based DSSCs. Indeed, the highest short-circuit current density (12.06 mA/cm2), open-circuit voltage (0.72 V), fill factor (0.58), and photoenergy conversion efficiency (5.04%) were those of the DSSC featuring PACI-S as the counter electrode.

Enhanced Linear and Non Linear Optical Activity of Lead Onto L-Threonine Cadmium Acetate Crystal

Herein, we describe the growth and characterization of new crystal lead doped L-Threonine cadmium acetate (LTCA). The supramolecular coordination compounds are crystallized by slow evaporation technique at ambient temperature. The X-ray diffraction techniques confirm monoclinic crystal system and the presence of lead onto the LTCA lattice. L-Threonine amino acids have the unique properties like zwitter ionic nature and molecular chirality, which improves the optical properties of the crystal. The linear optical parameters such as optical band gap and refractive indexes are estimated from Uv-Vis analysis. The variation of dielectric constant, dielectric loss with frequency is studied using LCR meter. Due to the electropositive character of lead the static permittivity increases. Magnetic behavior changes to paramagnetic nature due to the inclusion of lead. TG/DTA analysis suggests, the crystal is thermally stable up to 135.32°C. Using Nd-YAG laser the NLO property was studied and the crystal shows higher SHG efficiency than the LTCA crystal.

Structural, optical and electronic characteristics of non-stoichiometric nano cadmium sulfide

Samples of non-stoichiometric nano CdS1 − x were synthesized by a simple thermolysis method by lowering the ratio of thiourea relative to cadmium acetate as starting precursors; Cd(Ac):(1-x) thiourea (x = 0.0, 0.03, 0.05 and 0.1). X’pert HighScore Plus program manifested biphasic CdS (cubic and hexagonal) and the Rietveld analysis was utilized to match the structural and microstructure parameters of the formed samples. The possibility of formed CdS1 − xOx alloy due to the sulfur deficiency is also examined using the Rietveld method. A High-resolution transmission electron microscope imaging exhibited nano size particles with homogeneous morphology. Fourier transform infrared spectrometer was utilized to confirm the existence of O2 in CdS1 − x matrix. The bandgap energies for CdS1 − x are reduced below the values of energy gaps of CdS and CdO upon increasing the parameter (x) forming a band gap “bowing”. The photoluminescence (PL) emitted visible colors depending on the amount of sulfur deficiency and excitation wavelength used. The maximum PL intensity observed in CdS0.9 sample, confirmed the presents of oxygen inside the matrix. The influence of oxygen substitution or vacancies of sulfur on the electronic structure and optical features of CdS was also investigated applying density function calculations.

Contribution of the TROLC gene to the regulation of tobacco growth in response to stress factors.

The trolC gene refers to plast genes that have entered the genome of Nicotiana tabacum as a probable result of horizontal transfer from Agrobacterium rhizogenes. It was shown that the trolC gene is expressed in young tissues of wild type tobacco; however, the physiological functions of the product of this gene remain largely unknown. The aim of our work was to obtain transgenic tobacco plants expressing a fragment of the trolC gene under the control of the 35SCaMV promoter in an antisense orientation and to assess the growth parameters of their roots under the action of abiotic stress factors. For morphometric analysis, 8 lines of transgenic plants were used. The analysis of root growth under the action of sodium chloride (100 mM), cadmium acetate (100 μM) and hypothermia (12°C) was conducted. Transgenic plants were characterized by improved shoot growth parameters under normal conditions. The roots of transgenic plants grew more slowly under normal conditions and under the action of cadmium and hypothermia than in wild type plants. The product of trolC gene has a negative effect on shoot growth, a positive effect on root growth, and also participates in the regulation and maintenance of root growth under the action of cadmium and hypothermia.