M. Umadevi

Effect of potassium on structural, photocatalytic and antibacterial activities of ZnO nanoparticles

ZnO and potassium doped ZnO nanoparticles were synthesized through wet chemical method. The samples were characterized by UV, XRD, SEM, TEM and EDAX. XRD analysis reveals that the prepared nanoparticles exhibit hexagonal wurtzite structure. TEM and SEM analyses disclose that synthesized samples were porous structure with needle shape. It also confirms that potassium was dispersed on ZnO surface. The influence of potassium on ZnO surface modulates the degradation of textile dyeing wastewater by improving its rate of decomposition to 0.007 min−1 with decoloration. A better zone of inhibition of about 20 mm against Staphylococci aureus and Pseudomonas aernginosa by ZnO and potassium doped ZnO nanoparticles were measured. The findings suggest that these nanoparticles have the potential to be a good photocatalyst and applied in water treatment to inhibit the bacterial growth.

Tailoring of Morphology and Optical Properties of Bishydrazone-Capped ZnSe Nanorods

Hydrazone derivatives containing heterocyclic moieties have interesting ligational features. Various heterocyclic base ligands have been gradually used to synthesize nanomaterials; however, adapting task-specific ligand systems to guide the synthesis path towards desirable nanostructures and morphologies is rare. In this article, bishydrazone was used as a ligand to purposely modify the morphological structure of the zinc selenide nanostructures via wet chemical reaction method at room temperature. The as-prepared ZnSe nanorods are relatively uniform with an average diameter of ~100u2009nm at the core and top diameter of 8–10u2009nm. UV-Vis spectrum of the products displayed absorption maxima at 390u2009nm. Therefore, the obtained ZnSe nanorods may have promising applications in blue emitters, catalysts, and gas sensors. The presence of bishydrazone in the ZnSe nanorods is confirmed by the Fourier transform infrared spectrum. It would be expected that bishydrazone could be used to prepare other nanoscale metal selenides with special morphologies and improved properties on a large scale.

Large scale ZnTe nanostructures on polymer micro patterns via capillary force photolithography

A novel approach to prepare micro patterns ZnTe nanostructures on Si (100) substrate using thermal evaporation is proposed by capillary Force Lithography (CFL) technique on a self-assembled sacrificial Polystyrene mask. Polystyrene thin films on Si substrates are used to fabricate surface micro-relief patterns. ZnTe nanoparticles have been deposited by thermal evaporation method. The deposited ZnTe nanoparticles properties were assessed by Atomic Force Microscope (AFM), Scanning Electron Microscope (SEM). SEM studies indicated that the particles are uniform in size and shape, well dispersed and spherical in shape. This study reports the micro-arrays of ZnTe nanoparticles on a self-assembled sacrificial PS mask using a capillary flow photolithography process which showed excellent, morphological properties which can be used in photovoltaic devices for anti-reflection applications.