Chemically sprayed CdO: Cr thin films for formaldehyde gas detection and optoelectronic applications.

Chromium (Cr) doped CdO films are chemically sprayed and are characterized by their optical, electrical, structural, and microstructural characteristics. The thickness of the films is determined by spectroscopic ellipsometry. The cubic crystal structure with a superior growth along (111) plane of the spray-deposited films is confirmed from the powder X-ray diffraction (XRD) analysis. XRD studies also suggested that some of the Cd2+ ions were substituted by Cr3+ ions, and the solubility of Cr in CdO is minimal, to be around ∼0.75 wt%. The analysis by atomic force microscopy shows uniform distribution of grains throughout the surface, whose roughness is varied from 33 to 13.9 nm concerning Cr-doping concentration. The microstructures from the field emission scanning electron microscope reveal a smooth surface. The elemental composition is examined using an energy dispersive spectroscope. The micro-Raman studies carried out in room temperature endorse the presence of metal oxide (Cd-O) bond vibrations. Transmittance spectra are obtained using UV-vis-NIR spectrophotometer, and the band gap values are estimated from the absorption coefficient. The films show high optical transmittance (>75%) in vis-NIR region. A maximum optical band gap of 2.35 eV is obtained from 1.0 wt% Cr-doping. The electrical measurement (Hall analysis) confirmed the degeneracy nature and n-type semi-conductivity. The carrier density, carrier mobility, and dc-conductivity are increased for higher Cr-dopant percentage. High mobility (85 cm2V-1s-1) is observed for 0.75 wt% Cr-doping. The 0.75 wt% Cr-doping show a remarkable response to formaldehyde gas (74.39%).

Synthesis, crystal structure and Hirshfeld surface analysis of the ortho-rhom-bic polymorph of 4-bromo-N-(4-bromo-benzyl-idene)aniline.

The crystal structure of the title compound, C13H9Br2N [systematic name: (E)-N,1-bis-(4-bromo-phen-yl)methanimine], is a second polymorph (Form II) crystallizing in the ortho-rhom-bic space group Pccn. The first polymorph (Form I) crystallizes in the monoclinic space group P21/c [Bernstein & Izak (1975 ▸). J. Cryst. Mol. Struct. 5, 257-266; Marin et al. (2013 ▸). J. Mol. Struct. 1049, 377-385]. The mol-ecule is disordered about an inversion center situated in the middle of the C=N bond, similar to the situation in the monoclinic polymorph: the C=N bond length is 1.243 (7) Å. In the crystal, mol-ecules stack along the b-axis direction and are linked by C-H⋯π inter-actions. The inter-atomic contacts in the crystal for both polymorphs were studied by Hirshfeld surface analysis and have notable differences. The solid-state fluorescence spectrum of Form II shows an emission peak at ca 469 nm. The two-photon absorption coefficient measured from the open aperture Z-scan technique is 1.3 × 10 -11 m W-1, hence, Form II shows optical limiting behaviour.

Laser assisted anticancer activity of benzimidazole based metal organic nanoparticles.

Recent studies showed that the photothermal therapy can be effectively used for the targeted cancerous cells destruction. Hence, in the present study, benzimidazole based metal organic complex nanoparticles, dichloro cobalt(II) bis-benzimidazole (Co-BMZ) and dichloro copper(II) bis-benzimidazole (Cu-BMZ), were synthesized by reprecipitation method and their anti-cancer activity by means of photothermal effect has been studied. Transmission electron microscopy analysis shows that the particle size of Cu-BMZ is ∼100 nm and Co-BMZ is in the range between 100 and 400 nm. Zeta potential analysis ensures the stability of the synthesized nanoparticles. It is found that the nonlinear absorption of the nanoparticles increases with increase in laser power intensity. Phototoxicity of human lung cancer (A549) and the normal mouse embryonic fibroblast (NIH-3T3) cells was studied using a 650 nm laser. Even though both the cell lines were affected by laser irradiation, A549 cells show higher cell destruction and lower IC50 values than the normal cells. Docking studies were used to analyse the interaction site and the results showed that the Cu-BMZ molecules have higher dock score than the Co-BMZ molecules. The obtained results indicate that Cu-BMZ samples have lesser particle size, higher nonlinear absorption and higher interaction energy than the Co-BMZ samples.

Spectral, morphological, linear and nonlinear optical properties of nanostructured benzimidazole metal complex thin films.

Metal organic materials are widely investigated to find their suitability for nonlinear optical applications due to the advantage of combined organic and inorganic properties. In this work benzimidazole based metal organic thin films of dichlorobis (1H-Benzimidazole) Co(II) and dichlorobis (1H-Benzimidazole) Cu(II) were deposited by chemical bath deposition method. The deposited films were annealed at 100, 150 and 200 °C to investigate the effect of annealing on the properties of thin films. Surface homogeneity of the films was increased with the annealing temperature due to the surface diffusion of the films and the same was evidently shown by Raman spectroscopy and Atomic Force Microscopy studies. But annealing the films at 200 °C yielded bulk patches on the surface due to the distortion of molecules. Linear and nonlinear optical properties of the films annealed at 150 °C showed relatively higher transmittance and improved nonlinear optical properties than the other as prepared and annealed samples.

Growth, spectral, thermal, optical, mechanical and etching studies of l-lysine semi-maleate (l-LSM) single crystals.

Organic nonlinear optical material, l-lysine semi-maleate (l-LSM) single crystals were grown by slow cooling solution growth technique. The crystal system of grown l-LSM was confirmed by single crystal and powder X-ray diffraction analyzes. Functional groups of the grown crystal have been identified by Fourier Transform Infrared spectral analysis. The proton and carbon NMR spectral studies confirm the presence of hydrogen and carbon in the grown l-LSM. The melting and thermal decomposition temperatures of the crystal were determined using thermogravimetric (TG) and differential scanning calorimetry (DSC) analyses. Optical transparency, second harmonic generation efficiency, micro hardness, dielectric constant and loss, refractive index and birefringence have also been measured. Further, the growth patterns and dislocations present in the grown crystal are studied.

Structural, optical, mechanical and dielectric studies of pure and doped L-Prolinium trichloroacetate single crystals.

In the present work, pure and metal substituted L-Prolinium trichloroacetate (LPTCA) single crystals were grown by slow evaporation method. The grown crystals were subjected to single crystal X-ray diffraction (XRD), powder X-ray diffraction, FTIR, UV-Visible-NIR, hardness, photoluminescence and dielectric studies. The dopant concentration in the crystals was measured by inductively coupled plasma (ICP) analysis. Single crystal X-ray diffraction studies of the pure and metal substituted LPTCA revealed that the grown crystals belong to the trigonal system. Ni(2+) and Co(2+) doping slightly altered the lattice parameters of LPTCA without affecting the basic structure of the crystal. FTIR spectral analysis confirms the presence of various functional groups in the grown crystals. The mechanical behavior of pure and doped crystals was analyzed by Vickers's microhardness test. The optical transmittance, dielectric and photoluminescence properties of the pure and doped crystals were analyzed.

Analysis on structural, SHG efficiency, optical and mechanical properties of KDP single crystals influenced by Glycine doping.

Good quality single crystals of potassium dihydrogen orthophosphate (KDP) were grown with different doping concentration of Glycine by conventional solution technique in aqueous solution. X-ray diffraction study has been carried out in order to see the effect of dopant on the structural parameters of KDP. There is no additional phase was observed which was further confirmed by Raman spectroscopic analysis. The second harmonic generation efficiency was measured by using Kurtz powder technique. The relative second harmonic generation (SHG) efficiency of the grown crystals was found to be increased with doping concentration up to 2.5 mol%. Optical transmission study also revealed the same behaviour with enhancement up to 2.5 mol% concentration and later decreased but still higher than pure KDP. The mechanical strength was found to increase with increasing the doping concentration.

Synthesis, growth and characterization of L-lysinium(+)...L-lysinium(2+) dichloride perchlorate (LLDP) single crystals by Sankaranarayanan-Ramasamy method.

L-lysinium(+)...L-lysinium(2+) dichloride perchlorate was synthesized at ambient temperature and bulk single crystals were grown by conventional and Sankaranarayanan-Ramasamy methods. Crystals grown by these methods were subjected to single crystal X-ray diffraction, Fourier transform infrared, high resolution X-ray diffraction, Vickers microhardness and thermogravimetric/differential scanning calorimetric/differential thermal analyses. Further, the cut-off wavelength and optical transmittance of the grown crystals were determined by UV-vis-NIR spectrum. Linear refractive index (n(x)) of the crystal was measured using minimum deviation method for different wavelengths. Optical quality of the grown crystals was analyzed by conoscopic interference pattern and the birefringence was calculated using interferometric technique. Surface laser damage threshold of the crystal was determined using Nd:YAG laser. The nonlinear refractive index n(2) was measured through the Z-scan technique using low power continuous wave HeNe laser. Frequency and temperature dependent dielectric constant (ε(r)) and dielectric loss (tanδ) were measured.

Growth, structural, spectral, mechanical and optical properties of pure and metal ions doped sulphamic acid single crystals.

Bulk single crystals of pure and metal ions (Mn(2+), Cu(2+) and Ni(2+)) doped sulphamic acid (SA) have been grown by conventional and unidirectional solution growth methods. Intensities of powder X-ray diffraction peaks of metal ions doped SA reveal that these dopants enhanced the crystallanity. The peak broadening and intensity variation in some frequency regions in FT-IR spectra show the incorporation of dopants in the SA lattice. Mn(2+) and Cu(2+) doped SA single crystals show high crystalline perfection (FWHM 5.5arcs) compared to pure and Ni(2+) metal ions doped SA crystals. The grown pure and Mn(2+), Cu(2+) and Ni(2+) ions doped SA crystals have transparency in the order SA>Mn:SA>Cu:SA>Ni:SA. The hardness value of Ni(2+) doped crystal is relatively less than that of the pure and other metal ions doped SA crystals. Pure and Ni(2+) ions doped SA crystals possess high dielectric constants than that of Cu(2+) and Mn(2+) ions doped crystals. From the SEM micrograph analyses, it is observed that the doping of these metal ions modify the surface morphology of the grown crystals.

Growth and characterization of organic nonlinear optical crystal of 1-chloro-2,4-dinitrobenzene (CDNB).

Organic nonlinear optical crystal of 1-chloro-2,4-dinitrobenzene has been successfully grown by low temperature solution growth technique. Good optical quality single crystals of size 28 mm x 11 mm x 5mm are obtained. Grown crystals were subjected to X-ray powder diffraction analysis, FT-IR, FT-Raman, proton nuclear magnetic resonance (PNMR) and etching studies. Thermal properties of the grown crystals were studied by thermo gravimetric analysis (TGA) and differential thermal analysis (DTA). UV-vis studies show the cutoff wavelength is less than 400 nm. Nonlinear optical property of the crystal was studied by Kurtz powder technique using Nd:YAG laser and the crystal exhibits second harmonic generation property.