Plasmonic Resonances and Their Application to Thin-Film Solar Cell

This chapter furnishes the plasmonic properties of metal nanostructure and its application to thin-film solar cell. Plasmonics is an emerging branch of nanooptics where light metal interaction in subwavelength domain is studied. Metal supports surface plasmon resonance that has tunable signature, which depends on the morphology as well as surrounding media. These plasmonic resonances can be tuned in a broader range of solar spectra by changing several parameters such as size, shape and medium. Moreover, metals show scattering properties that could be utilized to enhance optical path length of photon inside the thin film of solar device. The chapter mainly focusses on the study of plasmonic resonance of smaller- and larger-sized metal nanoparticle using semi-analytical as well as numerical approach. For the estimation of optical properties like extinction spectrum and field profile of larger-sized nanoparticle, finite-difference time-domain (FDTD) method is used. The field distribution in both silver and gold nanoparticle cases has been plotted in ‘on’ resonance condition, which has a broader range of applications

A Perspective on Plasmonics within and beyond the Electrostatic Approximation

Plasmonic is an emerging branch of nanophotonics wherein the electromagnetic properties of nanoparticles are studied for variety of applications. The optics of nanoparticles is studied in terms of surface plasmon resonances and optical cross section. Initially the first principle approach has been used to study the plasmonic fundamentals known as electrostatic approach. Under this approach, various parameters are taken into account to observe the electromagnetic properties of plasmonic nanogeometries. This electrostatic model is only used to analyze the optical signature of smaller size plasmonic geometries. Therefore, for the estimation of optical properties of larger size nanoparticle numerical model (Discrete Dipole Approximation) has been used. The observed surface plasmon resonances could be useful in sensing field, SERS signal detection and thin film solar cell application

POLYHERBAL PREPARATION AND COMPARATIVE STUDIES ON DIET-INDUCED HYPERLIPIDEMIA

Objective: The objective of this research article is to develop and evaluate polyherbal preparation and comparative studies on diet-induced hyperlipidemia. Methods: After the extraction, pharmacognostical and phytochemical screening was done. The lipid-lowering activity of polyherbal formulation (T1, T2, T3, T4, and T5) may be attributed to the phytoconstituents present such as alkaloids, carbohydrates, steroids, proteins, tannins, carbohydrates, flavonoids, phenols, glycosides, and triterpenes. In acute oral toxicity study, there were no behavioral changes seen up to 4 h and no mortality was observed up to the end of 24 h even at the maximum tested dose level of 2000 mg/kg per oral. It was considered maximum safe dose. Male and female albino rats weighing 150–200 g were used for the study. Hydroalcoholic extract of all plants was prepared having a dose of 2000 mg/kg. The doses were selected according to the Organisation for Economic Cooperation and Development guideline no. 425. The procedure was divided into two phases: Phase I (observation made on day 1) and Phase II (observed the animals for the next 14 days of drug administration). Animals received a single dose of 2000 mg/kg. After the administration of Healthcare Administration, food was withheld for 3–4 h. If the animal dies, conduct the main test to determine the LD50. The study was conducted by measuring various parameters, namely, daily feed intake (g), water intake (ml), body weight (g), lipid profile high-density lipoprotein (HDL), low-density lipoprotein (LDL), CHL level (mg/dl), and blood glucose level (mg/dl). Results: Results showed a significant decrease in blood glucose level and serum lipid profile such as total cholesterol, LDL, and increasing serum HDL level, so could be useful in the treatment of hypolipidemia. Conclusion: Polyherbal formulations (T1, T2, T3, T4, and T5) have hypoglycemic activity and significantly improve lipid profile levels in diet-induced experimental rats

Effect of analyte concentration on the laser-induced plasma temperature and electron density in liquid matrix

In the present work, we report spectroscopic studies of laser-induced plasmas produced by focusing the second harmonic (532nm) of a Nd:YAG laser onto the laminar flow of a liquid containing chromium. The plasma temperature is determined from the coupled Saha-Boltzmann plot and the electron density is evaluated from the Stark broadening of an ionic line of chromium Cr(II)] at 267.7nm. Our results reveal a decrease in plasma temperature with an increase in Cr concentration up to a certain concentration level; after that, it becomes approximately constant, while the electron density increases with an increase in analyte (Cr) concentration in liquid matrix

Gallstone Magnesium Distributions from Optical Emission Spectroscopy

This work reports measurements of calcified gallstone elemental compositions using laser-induced optical emission spectroscopy. The experimental results support the importance of the magnesium concentration in gallstone growth. Granular stones reveal an increased magnesium concentration at the periphery of the granules, suggesting the inhibition of further growth. Non-granular gallstones reveal lower overall magnesium concentrations, but with higher values near the center