[en] Nanocomposites of conducting polyaniline (PAni) and cadmium sulphide (CdS) has been synthesized via in situ generation of CdS from highly reactive organometallic cadmium precursor i.e. dimethyl cadmium (DMCd) in N,N'-dimethyl formamide (DMF). UV-Vis absorption spectra of PAni-CdS nanocomposite showed λ_(max) at about 440-445 nm in addition to the bands present at ∼325 and ∼615 nm due to PAni. The absorption band at ∼440-445 nm is identified due to nanosized CdS particles indicating a blue shift of about >70 nm with respect to bulk CdS. The X-ray diffraction pattern showed broad peaks due to formation of nanoparticles of CdS in polyaniline matrix. Scanning electron microscopy (SEM) showed that the particles are in agglomerated form. Organometallic compound i.e. dimethyl cadmium (Me₂Cd) is used for the first time with polyaniline for CdS nano particles

[en] Cadmium selenide has been synthesized directly from cadmium chloride in aqueous N,N'-dimethylformamide (DMF) by the use of cycloocteno-1,2,3-selenadiazole or the element itself as the source of selenium. The dark brown powders that are the end-products of these reactions were characterized by reflectance spectroscopy, powder X-ray diffraction and scanning electron microscopy

[en] Silicon carbide (SiC) exhibits wide band gap (3.2 eV), excellent corrosion and oxidation resistance properties, that make it attractive as substrate material for electronic and optoelectronic devices. In single crystal form, SiC possesses excellent thermal conductivity; high breakdown field strength and saturated electron drift velocity. SiC single crystals are used for fabricating smaller and tougher electronic devices capable of operating at high temperatures and voltages. Impurity analysis in SiC single crystals is crucial as it significantly affects its electronic properties. Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES) is utilized to evaluate the major element, Si content in single crystal sample. The elements such as C, O, N and H were easily and reliably determined using Leco gas analyzers. The chemical analysis results showed presence of major elements silicon and carbon in stoichiometric ratio

[en] Lead sulphide and lead selenide have been prepared for the first time, by in situ reduction of elemental S or Se by using aqueous DMF or aqueous SFS as reducing agents and their reaction with lead acetate. The grayish-black powder has been characterized by powder XRD measurement, XPS and SEM/EDAX analysis. Powder X-ray diffraction pattern revealed that cubic PbE (E = S, Se) is formed with a little impurities of lead in case of PbSe. Slightly broader peaks in XRD measurement suggest small particles diameter in the powder. The particle size by using Scherrer's formula is found to be about 100 nm. Peaks due to free lead particles are observed in XPS and EDS (in case of PbSe) analysis and SEM analysis indicates agglomerated particles

[en] Poly(vinyl alcohol) (PVA) stabilized gold nanoparticles have been prepared in aqueous medium using two different reducing viz.; hydrazine hydrate, a stronger reducing agent and sodium formaldehydesulfoxylate (SFS), a slightly weaker reducing agent. SFS is used for first ever time for reduction of gold metal salt. The PVA stabilized gold nanoparticles solutions are wine red to blood red coloured and are stable over a long period of time with no indication of aggregation. The solution shows strong visible light absorptions in the range of 520-540 nm, characteristics of gold nanoparticles. Powder X-ray diffraction patterns of freshly prepared films containing gold nanoparticles indicated particles size to be about 15 nm. Transmission electron microscopy (TEM) of a more than two-week-old sample revealed well-defined non-agglomerated spherical particles of about 50 nm diameter in solutions

[en] Yellow and orange light emission from nanoparticles of cadmium sulphide embedded in polyvinyl alcohol (PVA) has been observed as thin films. The synthesis of CdS embedded in PVA has been performed via two different routes at room temperature and the composite films have been prepared by vacuum evaporation of solvent on a glass surface. The absorption spectra show a blue shift of more than 80 nm as compared to bulk CdS band-gap. The photoluminescence studies indicate the air stable light emission from the films. Bright light emission at 515 nm (2.41 eV) has been observed without using PVA

[en] HCl doped conducting polyaniline-CdS nanocomposite (PAni.HCl:CdS) has been prepared by via organometallic method in which dimethyl cadmium has been used as a source for cadmium. UV-vis absorption spectra of PAni.HCl:CdS nanocomposite showed λ _(max) at about 450-460 nm in addition to the bands at ∼320 and ∼600 nm due to polyaniline. The band at about ∼830 nm due to PAni.HCl decreased in intensity with increasing CdS ratio. The absorption band at ∼455 nm, slightly overlapped with the host absorption, is considered to be due to nanosized CdS particles. The greenish-black composite powder showed flaky morphology under scanning electron microscopy (SEM). X-ray diffraction (XRD) measurement showed broad pattern for hexagonal CdS with variation in particle diameter depending on the ratio between CdS and HCl doped polyaniline. The composite powder showed loss of conductivity with increasing CdS ratio with respect to polyaniline