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Mukhopadhyay G.,Indian Institute of Technology Bombay | Puri S.,Indian Institute of Technology Bombay | Puri S.,Stanford University | Mukhopadhyay P.,Center for Research in Nanotechnology and Science
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

We present here a mathematical formulation determining the enhancement factors of Raman scattered light from molecules adsorbed on to multiply coated ellipsoidal particles. We use this formulation to present enhancement of Raman scattering from molecules, such as pyridine and CV from nanoparticles of gold and silver as well as their core-shell structures with magnetic metal cobalt. The nanoparticles of these metals are widely used in biomedical applications. We also present results for the cases when the nanoparticle is covered with a monolayer of Raman active molecules and dispersed randomly in a medium. Our results can be of importance in medical technology. © 2010 SPIE.

Hema Sagar G.,Center for Research in Nanotechnology and Science | Tiwari M.D.,Center for Research in Nanotechnology and Science | Tiwari M.D.,Indian Institute of Technology Bombay | Bellare J.R.,Center for Research in Nanotechnology and Science | Bellare J.R.,Indian Institute of Technology Bombay
Journal of Physical Chemistry B | Year: 2010

Vesicles are usually characterized for their structure by microscopy or, less often, by the addition of fluorescent dyes in a flow cytometer. We present a new method of studying these structures and associated forms by forward and side scatter analysis on a flow cytometer which has the advantage of simultaneous handling of large population of vesicles to identify their shapes and lamellarities. The technique is suitable for several types of vesicular structures like Multivesicular vesicles (MVV), multilamellar and unilamellar vesicles. Characteristic signatures are given by tubular structures and fine features thereon allow detection of complex structures such as fused and ellipsoidal forms. Coexistence of tubular and spherical structures, such as those known to form when surfactants/salt solutions are diluted, can clearly be detected by the signature pattern, which separates into two distinctly identifiable populations. The population can be sorted or separated easily based on these signatures and such sorting has allowed us to confirm our findings by microscopic observations. This novel method can thus be used for concurrent observations of vesicle populations with dye or more advantageously without employing any fluorescent tag. © 2010 American Chemical Society.

More V.,Center for Research in Nanotechnology and Science | Shivade V.,Indian Institute of Technology Bombay | Bhargava P.,Indian Institute of Technology Bombay
Transactions of the Indian Ceramic Society | Year: 2016

Cleaning of the FTO substrate is being done to remove the debris present on the substrate during the fabrication of dye sensitized solar cells (DSSC’s). Sonication of FTO substrates by keeping it in soap solution, ethanol and distilled water followed by drying at 100°C has been reported by researchers. Some researchers have mentioned the use of ultr aviolet ozonization (UV-O3) processes to remove the organic contamination over FTO substrates. The present work shows the effect of cleaning of the FTO substrates on efficiency of the DSSC. Cleaning of FTOs was done by two methods – one by only bath sonication and other by bath sonication followed by heat treatment. It was found that heat treatment effectively removed organics compared to the non heat treated process. Heat treatment improved the performance of DSSC’s by enhancing the adhesion of titania film to the FTO substrate. © 2016 The Indian Ceramic Society

Bharadwaj R.,Center for Research in Nanotechnology and Science | Mukherji S.,Center for Research in Nanotechnology and Science | Mukherji S.,Indian Institute of Technology Bombay
Optical Sensors, 2014 | Year: 2014

The penetration depth of the localized surface plasmon evanescent field of a gold nanoparticle based fiber optic probe was estimated by measuring optical absorbance change at the resonance wavelength during the deposition of polyelectrolyte multilayers. © 2014 OSA.

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