Shraddha Agrawal

Antibacterial Properties of Silver Doped TiO2 Nanoparticles Synthesized via Sol-Gel Technique

In this work, antibacterial, micro-structural, and fluorescence properties of silver (Ag) doped TiO2 nanoparticles were studied to analyze the effect of silver for effective improvement in antibacterial properties of TiO2. Antibacterial properties of pure TiO2 and Ag-TiO2 was studied using Escherichia coli, Pseudomonas aeruginosa as Gram Negative and Bacillus subtilis, Staphylococcus aureus as Gram positive bacteria, as a model for Agar disc diffusion assay method. The concept of inhibition zone diameter was applied to observe the antibacterial activity of TiO2 and Ag-TiO2. It was observed that the antibacterial activity of TiO2 improves with doping of Ag. Fluorescence spectra confirm the red shift in band edge emission at excitation wavelength of 360 nm which shows effective fluorescence properties of these nanoparticles. Microstructures of these nanoparticles have studied with the help of transmission electron microscopy (TEM) and atomic force microscopy (AFM).

Structural, optical and transport properties of transition metals doped (A: Co, Ni and Cu) BiFe0.9A0.1O3

Nanoparticles of pure and Transition metals doped (Co, Ni and Cu) BiFeO3 of the composition BiFe0.9A0.1O3 (A = Co, Ni and Cu) have been successfully synthesized by sol gel auto combustion method using citric acid as a chelating agent and calcinated at 300°C. Microstructural analyses were done by XRD, TEM and SEM techniques. The crystallite size was resolute by powder X-ray diffraction technique whereas, UV-VIS technique was used to study the optical properties and band gap (Eg) of all samples. The variation of a. c. conductivity has been studied as function of frequency. It was observed that doping causes decreases in the ac conductivity of the nanoparticles as compared with the pure nanoparticles. It was also observed that doping of Transition Metals affects the optical properties effectively and band gaps were also increased.

Thermal properties of transition metals doped (A: Co, Ni and Cu) BiFe0.9A0.1O3

The synthesis of pure and transition metals (Co, Ni and Cu) doped BiFeO3nanoparticles, a promising G-type antiferromagnetic material have been done by auto combustion method using citric acid as a fuel. Microstructural analyses were done by XRD and FTIR. The thermal stability of the sample was determined by thermo gravimetric analysis (TGA) and heat flow rate was plotted by differential scanning calorimetric (DSC).

Microstructural and optical properties of sol gel synthesized CdS nano particles using CTAB as a surfactant

The stabilized pure CdS nanoparticles were synthesized using chemical precipitation method in aqueous medium using cadmium acetate and sodium sulphide with (CTAB) as a capping agent and their effect on surface morphology of nanoparticles. The obtained particles were characterized using X-ray diffraction studies (XRD and FTIR. The X-ray diffraction pattern revealed that the synthesized cadmium sulphide nanoparticles were polycrystalline nature. The temperature and frequency dependence of dielectric constant, dielectric loss and AC conductivities were studied over a range of the frequency 75Hz to 6MHz.

Room temperature optical and dielectric properties of Ca and Ni doped barium ferrite

The citrate sol gel combustion method has been used to synthesize (Ba0.9Ca0.1) (Fe0.8 Ni0.2)12O19 hexaferrites. Microstructural analyses were carried out by XRD and FTIR. Optical properties were studied by UV-visible technique in the range of 300-800 nm. The energy band gap was calculated with the help of Tauc relationship shows increases in band gap. Ca and Ni doped barium ferrite annealed at 850°C exhibit significant dispersion in complex permeability. The dispersion in complex dielectric constant can be explained on the basis of Koop’s theory based on Maxwell-Wagner two layer models in studied nanoparticles.

Auto-combustion synthesis and characterization of Mg doped CuAlO2 nanoparticles

The synthesis of pure and Mg doped Copper aluminumoxide CuAlO2nanoparticles, a promising p-type TCO (transparent conducting oxide) have been done bysol gel auto combustion method using NaOH as a fuel, calcinated at 600°C. The structural properties were examined by XRD and SEM techniques. The optical absorption spectra of CuAlO2 sample recorded by UV-VIS spectrophotometer in the range of 200 to 800 nm have been presented. The crystallite size was determined by powder X-ray diffraction technique. The electrical behavior of pure and Mg doped CuAlO2 has been studied over a wide range of frequencies by using complex impedance spectroscopy.The variation of a.c. conductivity has been studied as function of frequency and temperature. The data taken together conclude that doping causes decreases in the ac conductivity of the nanoparticles as compared with the pure nanoparticles. Mg doping affects the optical properties and band gap.

Microstructural and optical properties of CdS nanoparticles synthesized by sol gel method

Semiconductor nanoparticles of CdS are of great interest for both fundamental research and industrial development due to their unique size-dependent optical and electronic properties and their exciting utilization in the fields of light-emitting diode, electro-chemical cells, laser, hydrogen producing catalyst, biological label. We present a scheme to measure the optical properties of CdS nanoparticles The peaks were indexed by powder-x software. The XRD pattern analysis showed that CdS composition was found to have hexagonal structure with well crystalline nature. the surface morphology and the composition of the samples were investigated by SEM (JEOL, japan). The image shows the presence of large spherical aggregates of smaller individual nanoparticles of various sizes for pure cds. to check the chemical composition of the material, energy dispersive X-ray (EDX) spectroscopic analysis was also performed which further confirmed the presence of cd and s ions in the matrix. The optical absorption spectra of CdS sample was recorded by uv-vis spectrophotometer in the range of 200 to 800 nm.Semiconductor nanoparticles of CdS are of great interest for both fundamental research and industrial development due to their unique size-dependent optical and electronic properties and their exciting utilization in the fields of light-emitting diode, electro-chemical cells, laser, hydrogen producing catalyst, biological label. We present a scheme to measure the optical properties of CdS nanoparticles The peaks were indexed by powder-x software. The XRD pattern analysis showed that CdS composition was found to have hexagonal structure with well crystalline nature. the surface morphology and the composition of the samples were investigated by SEM (JEOL, japan). The image shows the presence of large spherical aggregates of smaller individual nanoparticles of various sizes for pure cds. to check the chemical composition of the material, energy dispersive X-ray (EDX) spectroscopic analysis was also performed which further confirmed the presence of cd and s ions in the matrix. The optical absorption spectra o...

Electrical and thermal properties of Ca and Ni doped barium ferrite

Ca and Ni doped M type Barium ferrite of the composition ((Ba0.9Ca0.1) (Fe0.8 Ni0.2)12O19) were prepared by the traditional sol gel auto combustion method using citric acid as a fuel. Microstructural analyses were carried out with the help of XRD and SEM. XRD analysis is the evidence of nanometer regime along with crystalline planes of hexagonal structure. It also confirms the hexagonal structure of barium ferrite even with the doping of Ca and Ni. SEM analysis is the signature of the spherical shape and surface morphology of agglomerated form of nano-powders of doped samples. The thermal properties of samples were carried out with the help of TGA. That shows the variation of weight loss of the prepared sample with the temperature.

Microstructural and thermal properties of pure BaFe12O19 and Sr doped barium ferrite (Ba0.9Sr0.1Fe12O19) synthesized by auto combustion method

Nanoparticles (NPs) of Pure BaFe12O19 and Strontium doped Barium Ferrite (Ba0.9Sr0.1Fe12O19) have been successfully synthesized by Auto combustion method using citric acid as a chelating agent and calcined at 450°C for 3 hrs and 850°C for 4 hrs. Microstructural studies were carried by XRD and SEM techniques. Structural studies suggest that the crystal system remains hexagonal even with the doping of Strontium. The XRD analysis confirms the formation of the structures in the nanometer regime and the peaks are the evidence of the crystalline phase. The SEM images shows the morphology of surface of the samples. The thermal property studied by TGA shows the weight loss which is with varying the temperature and weight loss also varies with Sr doping. The TGA analysis exhibits the loss of weight at different temperatures.