Shriwas Ashtaputre

Extracellular synthesis of silver nanoparticles by a silver-tolerant yeast strain MKY3

Silver nanoparticles in the size range of 2-5 nm were synthesized extracellularly by a silver-tolerant yeast strain MKY3, when challenged with 1 mM soluble silver in the log phase of growth. The nanoparticles were separated from dilute suspension by devising a new method based on differential thawing of the sample. Optical absorption, transmission electron microscopy, x-ray diffraction and x-ray photoelectron spectroscopy investigations confirmed that metallic (elemental) silver nanoparticles were formed. Extracellular synthesis of nanoparticles could be highly advantageous from the point of view of synthesis in large quantities and easy downstream processing.

Synthesis and analysis of ZnO and CdSe nanoparticles

Zinc oxide and cadmium selenide particles in the nanometer size regime have been synthesized using chemical routes. The particles were capped using thioglycerol in case of ZnO and 2-mercaptoethanol in case of CdSe to achieve the stability and avoid the coalescence. Zinc oxide nanoparticles were doped with europium to study their optical properties. A variety of techniques like UV-Vis absorption spectroscopy, X-ray diffraction (XRD), photoluminescence (PL), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM) were used to carry out structural and spectroscopic characterizations of the nanoparticles.

Synthesis and Characterization of Mercaptoethanol Capped Zinc Oxide Nanoparticles Capped with Organic Molecules

Synthesis of Zinc oxide (ZnO) nanoparticles has been carried out using a chemical route. Stability of the size has been achieved using mercaptoethanol as surface capping molecules. Infra red spectroscopy and x‐ray photoelectron spectroscopy analysis confirm the presence of capping molecules on the ZnO particle surface. Strong green photoluminescence was observed at ∼534 nm from all the nanoparticles.