scholarly journals Spectroscopic Studies on Films of Lead Nitrate Doped Polyvinyl Alcohol – Polyvinyl Pyrrolidone Blend

2018 ◽  
Vol 15 (1) ◽  
pp. 55-67 ◽  
Author(s):  
Preeti B. Hammannavar ◽  
Blaise Lobo
Keyword(s):  
Polyvinyl Alcohol ◽  
Fluorescence Intensity ◽  
Lead Nitrate ◽  
Photo Luminescence ◽  
Spectroscopic Studies ◽  
Polyvinyl Pyrrolidone ◽  
Luminescence Spectroscopy ◽  
Allowed Transition ◽  
Indirect Allowed Transition ◽  
Uv Visible

Films of polyvinyl alcohol (PVA) – polyvinyl pyrrolidone (PVP) blend doped with lead nitrate (Pb(NO3)2) were prepared by solution casting method, with doping level (DL) of Pb(NO3)2 in PVA – PVP polymeric blend varying from 2.7 up to 50.5 wt%. The prepared films were characterized using UV-Visible spectroscopy, fluorescence (or photo- luminescence) spectroscopy, FTIR and Raman spectroscopy. Parameters like optical band gaps due to indirect allowed transition (IAT) and direct allowed transition (DAT), as well as the activation energy (Ea) for optical transitions are extracted from the UV- Visible (or optical) spectra of these films. Objective of the FTIR, Raman and Fluorescence spectroscopic study is to understand the molecular chemical changes in PVA and PVP caused by the dopant (Pb(NO3)2). There is an enhancement of fluorescence intensity at DLs of 2.7 wt%, and at DL 7.6 wt%, the fluorescence intensity decreases (quenching). PVP acts as a capping agent for the dopant species, and is considered to be responsible for changes in fluorescence intensity. Signature of nitrate ion (NO3-) vibration is observed at wavenumber 1037 cm-1 in Raman spectra, and in the FTIR spectra, the NO3- vibration is seen at the wavenumber equal to 1380 cm-1.

scholarly journals New Brightener for Zn-Fe Alloy Plating from Sulphate Bath

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
B. M. Praveen ◽  
T. V. Venkatesha
Keyword(s):  
Grain Size ◽  
Metal Ion ◽  
Condensation Product ◽  
Spectroscopic Studies ◽  
Sem Images ◽  
Alloy Electrodeposition ◽  
Fine Grained ◽  
Polarization Studies ◽  
Uv Visible ◽  
Sulphate Bath

Zn-Fe alloy electrodeposition was carried out in the presence of condensation product 2-{[(1E)-(3,4-dimethoxyphenyl)methylidene]amino}-3-hydroxypropanoic acid formed between veratraldehyde and serine in acid sulphate bath. Hull cell was used for optimizing the operating parameters and bath constituents. During deposition, the potential was shifted towards cathodic direction in the presence of addition agents and brightener. The polarization studies show that deposition taking place in basic bath and optimum bath was 1.08 and 1.15 V, respectively. Current efficiency and throwing power were reached around 85% and 26%, respectively. The SEM images of bright deposit indicated its fine-grained nature and appreciable reduction in the grain size. XRD studies have showed that the grain size of the deposit generated from optimum bath was 16 nm. UV-visible spectroscopic studies confirm the formation of complex between metal ion and brightener.

Preparation of Triangular Silver Nanoparticles Using Polyvinyl Pyrrolidone with Different Concentration

2013 ◽  
Vol 873 ◽  
pp. 206-210
Author(s):  
Kai Li ◽  
Rao Fu ◽  
Qing Ran Gao ◽  
Ai Wei Tang ◽  
Ying Feng Wang
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Silver Nanoparticles ◽  
Driving Force ◽  
Ostwald Ripening ◽  
Polyvinyl Pyrrolidone ◽  
Protective Agent ◽  
Ag Nps ◽  
Transmission Electron ◽  
Uv Visible

This paper continues our previous work on preparation of triangular silver nanoparticles. The method proceeds with reaction of silver nitrate with hydrazine hydrate in the presence of polyvinyl pyrrolidone in aqueous solution. Effects of the concentration of PVP on the morphologies of Ag NPs were systematically investigated. The obtained Ag NPs were characterized by transmission electron microscopy and UV-visible spectrophotometer. The results showed that, triangular Ag NPs with edge lengths in the range of 50-200 nm were obtained using PVP as protective agent with lower concentration. As the concentration of PVP increased, spherical Ag NPs with their sizes about 6.2 nm were prepared and triangular Ag NPs were not obtained. The formation mechanism of triangular Ag NPs has been studied. Ostwald ripening is the driving force on the conversion of spherical Ag NPs to triangular Ag NPs in the presence of PVP.

A Newly Designed Cryostat for Absorption Spectroscopic Studies of Liquids, Solids, and the Interphases

1988 ◽  
Vol 42 (8) ◽  
pp. 1401-1404 ◽  
Author(s):  
J. C. Cornut ◽  
P. V. Huong ◽  
A. Graja ◽  
G. Daleau
Keyword(s):  
Solid State ◽  
Absorption Spectroscopy ◽  
Thermal Convection ◽  
Spectroscopic Studies ◽  
Sample Cell ◽  
Cold Stream ◽  
Uv Visible ◽  
Freezing Chamber

A double jacket cryostat based on thermal convection between a gaseous cold stream filled in a freezing chamber and the sample cell is described. This device is designed for absorption spectroscopy in the infrared and in the UV-visible regions for gases, liquids, liquefied gases, and solids, as well as for the transitions between these phases or between phases in the solid state, over the range 85 to 340 K, at variable thicknesses and under a pressure of up to 10 bars.

scholarly journals Spectroscopic studies on the potassium 1-fluorobenzoyltrifluoroborate salt by using the FT-IR, Raman and UV–Visible spectra and DFT calculations

2020 ◽  
Vol 1204 ◽  
pp. 127534 ◽  
Author(s):  
Maximiliano A. Iramain ◽  
Ana E. Ledesma ◽  
Elizabeth Imbarack ◽  
Patricio Leyton Bongiorno ◽  
Silvia Antonia Brandán
Keyword(s):  
Dft Calculations ◽  
Spectroscopic Studies ◽  
Visible Spectra ◽  
Ft Ir ◽  
Uv Visible

Hydrothermal Synthesis of GdVO4:Eu 3+ Phosphors by Optimizing its Preparation Conditions

2011 ◽  
Vol 287-290 ◽  
pp. 1360-1364
Author(s):  
Ying Lin Yan ◽  
Yun Hua Xu ◽  
Juan Wang ◽  
Zhen Xing Luan
Keyword(s):  
Ph Value ◽  
Photo Luminescence ◽  
Luminescence Spectroscopy ◽  
Temperature Reaction ◽  
Hydrothermal Temperature ◽  
Red Emission ◽  
X Ray ◽  
Preparation Conditions ◽  
Optimal Reaction Condition ◽  
Optimal Reaction

Eu3+ -doped GdVO4 powders have been synthesized via a novel hydrothermal method using commercially available Gd2O3, NH4VO3 and Eu2O3 as the reacting precursors. The influences of several important parameters, such as hydrothermal temperature, reaction time and pH value, of the experiment were investigated. The obtained samples were characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), and photo-luminescence spectroscopy (PL). The experimental results showed that the optimal reaction condition was processed at 180°C for 12 h and adjusted pH value to 4. The morphology of products was uniform pseudo-octahedron with a little conglomeration. All the phosphors exhibit the characteristic dominant red emission of Eu3+ ion (5D0 → 7F2) at 618nm.

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