Bikash Chandra Nath

Synthesis and evaluation of antioxidant and antibacterial behavior of CuO nanoparticles

CuO nanoparticles were synthesized by thermal decomposition methods and characterized by UV-visible spectroscopy, XRD and TEM analysis. The resultant particles are nearly spherical and particle size is in the range of 15-30 nm. The antioxidant behavior of synthesized CuO nanoparticles was evaluated by scavenging free radicals of 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH). The free radical scavenging activity of CuO nanoparticles was monitored by UV-visible spectrophotometry. The antibacterial activity of CuO nanoparticles was tested against different bacterial strains. CuO nanoparticles showed efficient antioxidant activity and bactericidal effect against Eschericia coli and Pseudomonas aeruginosa.

Synthesis of ZnO nanoparticles and evaluation of antioxidant and cytotoxic activity.

ZnO nanoparticles were synthesized by thermal decomposition method and were characterized by UV-vis spectroscopy, XRD, SEM, EDX and TEM analysis. The resultant nanoparticles are nearly spherical and size is in the range of 40-50 nm. The antioxidant behavior of ZnO nanoparticles was assessed by scavenging free radicals of 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) with varying nanoparticle concentration and time interval individually. The DPPH scavenging activity was monitored by UV-vis spectrophotometer. ZnO nanoparticles were also showing cytotoxic activity which was studied by hemolytic potentiality test.

An efficient quasi solid state dye sensitized solar cell based on polyethylene glycol/graphene nanosheet gel electrolytes

A poly(ethylene glycol)/graphene nanosheet quasi solid gel electrolyte was synthesized using an in situ polymerization technique for dye-sensitized solar cells (DSSCs). Fabrication of the DSSCs was carried out by sandwiching the poly(ethylene glycol)/graphene nanosheet (PEG/graphene nanosheet) gel electrolyte in between the dye sensitized TiO2 nanoflower photoanode and platinum based counter electrode using a spacer of thickness 25 μm. However, the graphene nanosheets form a network with PEG matrix channels in the gel electrolyte which enhances charge transportation. The PEG/graphene nanosheet gel electrolyte was characterized using Fourier transform infrared spectroscopy, cyclic voltammetry, scanning electron microscopy, transmission electron microscopy, thermal gravimetric analysis, atomic force microscopy and electrochemical impedance spectroscopy. Electrochemical impedance spectroscopy results demonstrate the reduction of charge transfer resistance (Rct) with the incorporation of graphene nanosheets which promotes charge transportation through the gel electrolyte. The reduction of (Rct) enhances the device efficiency which was observed in the current density vs. voltage (J–V) measurements and thereby the incident photon to converted electron (IPCE) curves. The maximum photovoltaic conversion efficiency of 5.16% was achieved.

Designing hierarchical NiO/PAni-MWCNT core–shell nanocomposites for high performance super capacitor electrodes

A novel type of nanocomposite material based on multi walled carbon nanotubes (MWCNT) and NiO nanoparticles coated with polyaniline (PAni) has been prepared by an in situ polymerization technique. Transmission electron microscopy confirms the core–shell structure of the composite. TG-analysis reveals that NiO/PAni-MWCNT nanocomposites exhibit better thermal stability than NiO-PAni. The synthesized nanocomposites have good conductivity and excellent electrochemical properties. The specific capacitance values of these composites were measured from their galvanostatic charge–discharge curves. The particles show a high value of specific capacitance and can find potential application as super capacitor electrodes.

Development of Dye-Sensitized Solar Cells Based on Gold/Gelatin Gel Electrolyte: Effect of Different Aspect Ratio of Gold Nanocrystals

This study describes the application of gold/gelatin (Au/gelatin) gel electrolyte to a set of quasi-solid-state dye-sensitized solar cells (DSSCs). A set of DSSC based on Au/gelatin gel electrolyte was developed. Au nanocrystals of different aspect ratio were synthesized and immobilized in gelatin gel electrolyte. The structures of the synthesized nanocrystals and nanocomposite gel were confirmed by using Fourier transform infrared spectroscopy, a scanning electron microscopy energy-dispersive X-ray, and transmission electron microscopy analysis. The thermogravimetric analysis indicated that introduction of Au nanocrystals to the polymer matrix resulted in an increase in thermal stability. Fabricated DSSC was exposed to a 100-mW/cm2 solar simulator in ambient atmosphere. It was observed that the photoconversion efficiency (PCE) changes with different aspect ratio of Au. In addition, significantly high open-circuit voltage (Voc), current density (Jsc), and PCE of 0.656 V, 4.94 mA · cm-2, and 1.975%, respectively, are found for Au nanocrystals with maximum aspect ratio of 3.5 at an optimum concentration of 0.04%.