Systematic study on structural phase behavior of CdSe thin films

Cadmium selenide (CdSe) thin films were chemically deposited at room temperature, from aqueous ammoniacal solution using Cd(CH(3)COO)(2) as Cd2+ and Na(2)SeSO(3) as Se2- ion sources. The as-deposited films were uniform, well adherent to the glass substrate, specularly reflective, and red-orange in color. The as-deposited CdSe layers grew with nanocrystalline sphalerite cubic structure along with the amorphous phase present in it, with optical band gap E(g) = 2.3 eV. The films were annealed in air atmosphere for 4 h at different temperatures and characterized for compositional, structural, morphological, and optical properties. XRD and SEM studies clearly revealed the systematic phase transformation of CdSe films from metastable nanocrystalline cubic (zinc blende type) to a mixture of cubic and hexagonal (wurtzite type), and finally into stable hexagonal through different intermediate phases with an improvement in the crystal quality. The films showed a red shift in their optical spectra after annealing.     

1-Decanethiol, a new reagent for the odorless deprotection of aryl methyl ethers

1-Decanethiol has been found to be an excellent reagent for the deprotection of aryl methyl ethers. This newly developed protocol afforded the corresponding phenols in good to excellent yields. A clear advantage of 1-decanethiol over the more commonly used thiols is the easy extraction of both the deprotecting reagent and the reaction byproduct into the aqueous phase, which allows an essentially odorless work-up.     

Lattice engineering route for self-assembled nanohybrids of 2D layered double hydroxide with 0D isopolyoxovanadate: chemiresistive SO2 sensor

Tuning the interior chemical composition of layered double hydroxides (LDHs) via lattice engineering route is a unique approach to enable multifunctional applications of LDHs. In this regard, the exfoliated 2D LDH nanosheets coupled with various guest species lead to the lattice-engineered LDH-based multifunctional self-assembly with precisely tuned chemical composition. This article reports the synthesis and characterization of mesoporous zinc–chromium-LDH (ZC-LDH) hybridized with isopolyoxovanadate nanohybrids (ZCiV) via lattice-engineered self-assembly between delaminated ZC-LDH nanosheets and isopolyoxovanadate (iPOV) anions. Electrostatic self-assembly between 2D ZC-LDH monolayers and 0D iPOV significantly altered structural, morphological, and surface properties of ZC-LDH. The structural and morphological study demonstrated the formation of mesoporous interconnected sheet-like architectures composed of restacked ZCiV nanosheets with expanded surface area and interlayer spacing. In addition, the ZCiV nanohybrid resistive elements were used as a room-temperature gas sensor. The selectivity of ZCiV nanohybrid was tested for various oxidizing (SO₂, Cl₂, and NO₂) gases and reducing (LPG, CO, H₂, H₂S, and NH₃) gases. The optimized ZCiV nanohybrid demonstrated highly selective SO₂ detection with the maximum SO₂ response (72%), the fast response time (20 s), low detection limit (0.1 ppm), and long-term stability at room temperature (27 ± 2 °C). Of prime importance, ZCiV nanohybrids exhibited moderately affected SO₂ sensing responses with high relative humidity conditions (80%–95%). The outstanding SO₂ sensing performance of ZCiV is attributed to the active surface gas adsorptive sites via plenty of mesopores induced by a unique lattice-engineered interconnected sheet-like microstructure and expanded interlayer spacing.     

Application based Studies of HPTLC-bioautography in Evaluation of Botanicals: a Review

Journal of Analytical Chemistry - HPTLC is a widely used tool in standardization of herbs because of its ability to estimate the presence of active components in samples. HPTLC-bioautography is a...     

Lanthanum sulfide-manganese sulfide/graphene oxide (La2S3-MnS/GO) composite thin film as an electrocatalyst for oxygen evolution reactions

Journal of Solid State Electrochemistry - In this study, the lanthanum sulfide-manganese sulfide (La2S3-MnS) nanosheet composite films with different thicknesses were grown on graphene oxide (GO)...     

High temperature magnetic ordering in La2RuO5

Magnetic susceptibility, heat capacity and electrical resistivity measurements have been carried out on a new ruthenate, La₂RuO₅ (monoclinic, space group P2₁/c) which reveal that this compound is a magnetic semiconductor with a high magnetic ordering temperature of 170 K. The entropy associated with the magnetic transition is 8.3 J/mol K close to that expected for the low spin (S=1) state of Ru⁴⁺ ions. The low temperatures specific heat coefficient γ is found to be nearly zero consistent with the semiconducting nature of the compound. The magnetic ordering temperature of La₂RuO₅ is comparable to the highest known Curie temperature of another ruthenate, namely, metallic SrRuO₃, and in both these compounds the nominal charge state of Ru is 4+.     

A New Class of Bianchi Type-I Cosmological Models in Lyra Geometry

This paper deals with Bianchi type-V cosmological models of the universe filled with a bulk viscous cosmic fluid in the framework of general relativity. A new class of exact solutions has been obtained by considering various well established power law relations among scale factor, cosmological and gravitational constants and cosmic time. Some physical and geometrical behaviors of the models have also been discussed. It has been found that all the models are in fair agreement of observational results.     

Studies of magnetite nanoparticles synthesized by thermal decomposition of iron (III) acetylacetonate in tri(ethylene glycol)

In this paper, water-soluble magnetite nanoparticles have been directly synthesized by thermal decomposition of iron (III) acetylacetonate, Fe(acac)₃ in tri(ethyleneglycol). Size and morphology of the nanoparticles are determined by transmission electron microscopy (TEM) and dynamic light scattering (DLS) measurements while the crystal structure is identified using X-ray diffraction (XRD). Surface charge and surface coating of the nanoparticles are recognized using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectra (XPS) and zeta potential measurements. Magnetic properties are determined using vibrating sample magnetometer (VSM) and superconducting quantum interference device (SQUID) measurements. The results show that as-prepared magnetite nanoparticles are relatively monodisperse, single crystalline and superparamagnetic in nature with the blocking temperature at around 100 K. The magnetite nanoparticles are found to be highly soluble in water due to steric and electrostatic interactions between the particles arising by the surface adsorbed tri(ethyleneglycol) molecules and associated positive charges, respectively. Cytotoxicity studies on human cervical (SiHa), mouse melanoma (B16F10) and mouse primary fibroblast cells demonstrate that up to a dose of 80 μg/ml, the magnetic nanoparticles are nontoxic to the cells. Specific absorption rate (SAR) value has been calculated to be 885 and 539 W/gm for samples with the iron concentration of 1 and 0.5 mg/ml, respectively. The high SAR value upon exposure to 20 MHz radiofrequency signifies the applicability of as-prepared magnetite nanoparticles for a feasible magnetic hyperthermia treatment.     

Efficient dye-sensitized solar cells based on surfactant-mediated TiO2 nanostructures

Journal of Solid State Electrochemistry - Dye-sensitized solar cells (DSSCs) based on TiO2 nanostructures have attracted much attention due to their high photoconversion efficiency. Here, we report...     

CZTS counter electrode in dye-sensitized solar cell: enhancement in photo conversion efficiency with morphology of TiO2 nanostructured thin films

Journal of Solid State Electrochemistry - In the present investigation, kesterite phase Cu2ZnSnS4 (CZTS) nanoparticle, and one-dimensional (1D) nanorods and three-dimensional (3D) flower-like...