Siddhartha Sankar Nath

ZnO: PVP Quantum Dot Ethanol Sensor

We prepare of ZnO quantum dots embedded in polyvinylpyrrolidone (PVP) matrix and report it’s working as ethanol sensor. The samples have been prepared via quenching technique where bulk ZnO powder is calcined at very high temperature of 1200°C and then quenched into ice cold polyvinylpyrrolidone solution. Thee acteiut the samples specimen have been characterized by using UV/VIS spectroscopy, X-ray diffracttion study and high resolution transmission electron microscopy (HRTEM). These studies indicate the sizes of quantum dots to be within 10 nm. The prepared quantum dot samples have been examined for ethanol vapour sensing by exploring the variation of their resistance with time at different operating temperatures. It has been revealed that ZnO quantum dots can sense ethanol at low operating (230°C) temperature with less response time.

Synthesis and characterization of one pot synthesized PVA capped PbS quantum dots

The properties of materials drastically change when matter performs a transition from bulk to nano size. The quantum dots (QDs) of lead sulphide (PbS) embedded into Polyvinyl alcohol (PVA) are synthesized via one pot synthesis chemical method. The specimen has been analyzed by UV/VIS absorption spectroscopy, High resolution transmission electron microscopy (HRTEM) and fluorescence spectroscopy. Quantum Dot size is calculated from the absorption spectra using hyperbolic band model and sizes of the dots are found to be around 6nm and the calculated value is in agreement with the size as determined by HRTEM. The photoluminescence spectra was also obtained for the samples.

Lie Algebraic Study of Infra-Red Active Spectra of Single-Layer Graphene

In this article, using Lie algebraic technique and the expressions of the matrix elements of Majorana and Casimir operators, we obtain an effective Hamiltonian operator, which conveniently describes some stretching infra-red active mode of vibrations of monolayer graphene model of 30 atoms. The model finds the accuracy in results of density functional theory.

Synthesis and Characterization of Linoleic Acid Capped Palladium Nanoparticles

Many chemical reduction methods have been used to synthesize palladium nanoparticles from palladium salts. Here palladium nanoparticles have been synthesized through the chemical reduction of palladium ions by ethanol using linoleic acid as a protecting agent, which is then dispersed in chloroform to form homogeneous colloidal solution. Transmission electron microscope (TEM) reveal that the particles are mostly spherical in shape with an average size of nearly 6 nm. Fourier Transform infrared spectroscopy confirms the capping of these nanoparticles by linoleic acid. The UV/Vis absorption spectra show absorption peak at 390 nm which is due to surface plasmon resonance (SPR).