Structural and optical properties of laser irradiated nano structured cadmium oxide thin film synthesized by sol-gel spin coating method

Cadmium oxide CdO nanostructured thin films are synthesized using sol-gel spin coating method. The prepared samples of CdO thin films are irradiated with 10 mJ laser from pulsed Q-Switched Nd:YAG laser at 1064 and 532 nm wavelength. The samples were exposed to 45 pulses of 7 ns pulse duration. Morphology and structural analysis were carried out with scanning electron microscope (SEM) micrographs and X-ray diffraction (XRD) patterns. Optical investigations were obtained with spectrometer and fluorospectrometer from Shimadzu. SEM micrographs confirm the nanostructure of the CdO film and indicate agglomeration of nanoparticles with laser irradiation. XRD patterns show decrease in the intensity of orientation peaks after laser irradiation. Variation in band gap energy, absorption peaks, and photoluminescence spectra with laser irradiation are observed.     

Effective sequestration of Congo red dye with ZnO/cotton stalks biochar nanocomposite: MODELING,reusability and stability

Widespread application of dyes and disposal of their untreated effluents into water bodies adversely affect the ecosystem due to their complex aromatic structures and persistent nature. The present study aims to utilize the cotton stalks biochar (CSB) and its composite with zinc oxide nanoparticles (CSB/ZnONPs) to evaluate for the decontamination their batch scale potential of Congo red dye from wastewater. The characterization of CSB and CSB/ZnONPs was performed with Fourier-transform infra-red (FTIR) spectroscopy, scanning electron microscopy, energy-dispersive X-ray (EDX) and point of zero charge (PZC) to get insight of their potential for the decontamination of CR. The effects of initial CR concentration (25–500 mg/L), dosage of CSB and CSB/ZnONPs (0.5–2 g/L), solution pH (2–10) and contact time (0–180 min) were evaluated on CR removal at temperature (25 ± 1.5 °C). The results disclosed that CSB/ZnONPs showed excellent adsorption potential (556.6 mg/g) in comparison with CSB (250 mg/g) and most of the other adsorbents previously studies in the literature. The equilibrium experimental data were equally explained with Freundlich and Langmuir isotherm models (R² > 0.98) while kinetic data demonstrated the best fit with pseudo second order model. The CSB/ZnONPs composite exhibited excellent reusability (89.65%) after five adsorption/desorption cycles for the sequestration of CR from contaminated systems. The present study demonstrated that metallic nanocomposite of CSB (CSB/ZnONPs) is an excellent candidate for the cost effective and environment friendly decontamination of CR from industrial wastewater and is suggested to be considered for the decontamination of other pollutants from the wastewater.     

Synthesis of silver nanoparticles using root extract of Duchesnea indica and assessment of its biological activities

Treatment of microbial infections and inflammatory conditions have many challenges in terms of efficacy and safety issues. Novel approaches such as nanoparticles based drug delivery system have shown promising results to solve some of these problems. The aim of this study was to exploit the efficacy of the synthesized silver nanoparticles. In this study, silver nanoparticles (AgNPs) were biosynthesized using root extract (aqueous) of Duchesnea indica. They were characterized using different techniques such as, ultraviolet–visible (UV–Vis) spectrophotometry, transmission and scanning electron microscopy (TEM and SEM), X-ray diffractometer (XRD), energy dispersive X-ray spectroscopy (EDX), fourier-transform infrared spectroscopy (FTIR) and zetasizer. The UV–Vis spectra gave a characteristic peak at 423 nm; XRD confirmed its crystalline structure; FTIR confirmed the involvement of phytochemicals in their capping and reduction; TEM images confirmed their spherical shape with average width of 20.49 nm and average area of 319.25 nm². Various biological activities were performed on these NPs, such as antimicrobial, anti-inflammatory, analgesic and muscle relaxant, which showed significant results as follow. Among bacterial strains, Salmonella typhi (MIC: 0.01 mg/ml) and Escherichia coli (MIC: 0.01 mg/ml), while among that of fungal Microsporum canis (MIC: 0.53 mg/ml) and Alternaria alternata (MIC: 0.51 mg/ml) were most susceptible. The AgNPs showed maximum anti-inflammatory activity (46.15 and 56.85%) at 20 mg/kg after 3 and 5 h of drug administration, comparable to that of standard. In-vivo model exhibited concentration dependent inhibition of both COX-2 and 5-LOX enzymes. Similarly, it exhibited maximum analgesic activity (54.24%) at 20 mg/kg dose after 60 min. of pain induction. Furthermore, they depicted maximum muscle relaxation (P < 0.01) after 60 and 90 min of drug administration. Above results suggest that these AgNPs can be studied further for the development of more effective and safe formulations.     

Analysis of alumina-based titanium carbide composites by laser-induced breakdown spectroscopy

In this work, alumina (Al₂O₃) containing different volume % of titanium carbide (TiC) ranging from 0 to 30 were consolidated by the novel spark plasma sintering. The spectroscopic analysis of the plasma generated by irradiation of laser Nd:YAG (λ = 1,064 nm) on different concentrations of the composites in air atmospheric pressure was performed. The qualitative examination of the composites confirms the presence of aluminum, titanium, and carbon as major elements, while magnesium and sodium have been found as minor trace elements. Plasma parameters were estimated by assuming the LTE conditions for optically thin plasma. The electron density and temperature were evaluated by using the Stark broadening and intensity of selected aluminum emission lines, respectively. The addition of TiC to Al₂O₃ shows a linear behavior with plasma temperature corroborated by the calibration curve of Ti in the composites. The results suggest that calibration curve between plasma temperature and the composites can be used to estimate different concentrations of TiC in Al₂O₃ without analyzing the whole elements in the composites and thus opens up new applications of LIBS in ceramic industry.     

Effects of 1064 nm laser on the structural and optical properties of nanostructured TiO2 thin film

TiO₂ thin film has been widely used as photoelectrode in dye-sensitized solar cells. It can also be used in quantum dot synthesized solar cells. Study of its effects in different spectrum of light is important for its use in solar cells. We have reported effects of 1064 nm laser on the surface morphology, structural and optical properties of nanostructured TiO₂ thin film deposited on glass substrates using sol-gel spin coating technique. Q-Switched Nd:YAG pulsed laser at various power densities is used in this study. Surface morphology of the film is investigated using X-ray diffraction (XRD) and atomic force microscopy technique. The XRD pattern of as deposited TiO₂ thin film is amorphous and after laser exposure it became TiO₂ anatase structure. Atomic force microscopy of the crystalline TiO₂ thin film shows that the grain size increases by increasing laser power density. The calculations of the band gap are carried out from UV/Visible spectroscopy measurements with JASCO spectrometer. For laser power density of 25 MW/cm² there is an increase in the transmission and it decreases at the value of 38 MW/cm² and band gap decreases with increasing laser power density. Photoluminescence spectra of the crystalline TiO₂ thin film indicate two broad peaks in the range of 415 and 463 nm, one for band gap peak (415 nm) and other for oxygen defect during film deposition process.     

Structural changes in tin oxide thin film with laser exposure

The effects of laser irradiation on the surface, structure and optical properties of SnO thin films deposited on glass substrates using electron beam evaporation, are investigated. The thin film samples are irradiated using fundamental beam at 1064 nm from Q-switched Nd:YAG pulsed laser with different power densities. Structural morphology of the film is investigated using XRD patterns and AFM image. Both XRD pattern and AFM image show increase in grain size of the film with increasing laser power density. Other optical phenomena, photoluminescence emission, transmission, refractive index determination and optical band gaps calculations are also carried out at various laser power densities. Results from all these investigations reveal expansion in grain size of the crystalline SnO thin film with increasing laser power density.     

A comparative study of structural, thermal and electrical properties of undoped and doped with dodecylbenzenesulphonic acid polypyrrole

Polypyrrole was synthesized and doped with dodecylbenzenesulphonic acid; the latter was confirmed by means of FTIR spectroscopy. The percentage of crystallinity of synthesized polymers was estimated from X-rays diffraction studies. The formation of flaky structure in doped polypyrrole was observed by means of SEM. DC conductivity was found to be influenced by dopant dodecylbenzenesulphonic acid. Temperature dependant DC shows three dimensional variable ranges hopping (3D VRH). Activation energy, density of states and hopping length were calculated and found to be influenced by adding dopant to polypyrrole. The doped polypyrrole was found to be more thermally stable as compared to that of pristine polypyrrole.