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Your search keyword '"Pradyumnan, P. P."' showing total 6 results
Start Over Author "Pradyumnan, P. P." Topic zinc oxide
6 results on '"Pradyumnan, P. P."'

1. Waste heat energy harvesting by using praseodymium, nickel codoped zinc oxide thermoelectric materials.

Author

Soumya, C. and Pradyumnan, P. P.

Subjects
*ENERGY harvesting, *WASTE heat, *PRASEODYMIUM, *ZINC oxide, *ENERGY consumption, *BISMUTH telluride, *THERMOELECTRIC materials
Abstract

ZnO is a semiconductor with immense potential to use in different technological applications including in non-conventional energy generation such as thermoelectric generators and sensors. Herein, we investigated the thermoelectric properties of praseodymium and nickel codoped ZnO microcrystals. Structural studies and the optical band gap reduction confirmed the inclusion of the dopants into the host lattice. The codoping of praseodymium and nickel causes an increment in carrier density, which enhances the electrical conductivity of the materials. The energy filtering effect leads to the highest Seebeck coefficient of − 716 µV K−1. Simultaneous increments in electrical conductivity and the Seebeck coefficient enhanced the power factor of the doped materials. The doping of praseodymium ions with nickel ions induces more lattice distortions, which resulted in the drastic reduction of thermal conductivity from 17.8 W/mK to 3.7 W/mK. Enhancement of power factor with a significant reduction in thermal conductivity leads to a three-fold improvement in the thermoelectric figure of merit of ZnO materials. [ABSTRACT FROM AUTHOR]

Published
2023
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3. Synthesis and characterizations of nickel doped zinc oxide.

Author

Soumya, C., Pradyumnan, P. P., Manoj, P K, Siyad, M A, Beegum, Shargina, and Anas, S

Subjects
*ZINC oxide, *NICKEL (Coin), *BAND gaps, *ZINC oxide synthesis, *OPTICAL properties
Abstract

Nickel doped zinc oxide (Zn1-x O, x=0wt%, 1 wt%, 2wt %) were synthesized via solid state reaction method. The structural and optical characterizations were carried out with the prepared samples. Structural characteristics were determined by X- ray diffraction method, Raman spectroscopic analysis. Optical property studies of the sample were done through the UV-VIS- spectral analysis. The structural studies confirmed the hexagonal wurtzite structure of zinc oxide and the spectroscopic analysis shows a decrease in optical band gap from 3.37eV to 2.9eV. [ABSTRACT FROM AUTHOR]

Published
2020
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4. Enhanced power factor in Ho 3+ doped ZnO: A new material for TE Application.

Author

Pradyumnan, P. P., Paulson, Anju, N. A., Muhammed Sabeer, and N., Deepthy

Subjects
*THERMOELECTRICITY, *SEEBECK coefficient, *ELECTRIC conductivity, *ELECTRIC power factor, *ZINC oxide
Abstract

In this work we investigate the structural, chemical and thermoelectric property of Ho doped ZnO based material as a function of temperature. The thermoelectric properties were measured in a temperature 100-700 °C and found that Holmium doped samples posses a remarkable effect on transport properties in pure ZnO. Negative thermopower ensured that electrons are the majority charge carriers. Seebeck Coefficient and resistivity are found to be lower for the Holmium doped samples results for the enhancement in power factor. Power factor corresponding to 0.9 wt % doped Ho is found to be 0.57*10 -4 W/mK2,so that it can be considered as a potential candidate for thermoelectric application. [ABSTRACT FROM AUTHOR]

Published
2017
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5. ZnO:Gd Nanocrystals For Fluorescent Applications.

Author

Divya, N. K. and Pradyumnan, P. P.

Subjects
*ZINC oxide, *GADOLINIUM compounds, *NANOCRYSTALS, *FLUORESCENCE spectroscopy, *SOLUBILITY, *CHEMICAL sample preparation
Abstract

Gadolinium doped ZnO crystals within the solubility limit of gadolinium in ZnO matrix were prepared by solid state reaction technique. The method is relatively less expense and enables the production in large scale. The samples were characterised by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), UV/Vis diffuse reflectance spectroscopy and photoluminescence techniques. Fluorescent property studies of gadolinium doped ZnO at room temperature show enhanced visible light emission due to the defects and oxygen vacancies produced via doping. This work reports the impact of gadolinium doping in the structural, optical and luminescent properties of ZnO in detail. [ABSTRACT FROM AUTHOR]

Published
2016
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6. Structural and Physical Property Analysis of ZnO–SnO2–In2O3–Ga2O3 Quaternary Transparent Conducting Oxide System.

Author

Jayaram, P., Jaya, T.P., Karazhanov, Smagul Zh., and Pradyumnan, P.P.

Subjects
ZINC oxide, TIN oxides, INDIUM oxide, CHROMIUM-cobalt-nickel-molybdenum alloys, METAL powders, SOLID state chemistry
Abstract

The increasing demand in the diverse device applications of transparent conducting oxides (TCOs) requires synthesis of new TCOs of n- or p-type conductivity. This article is about materials engineering of ZnO–SnO2–In2O3–Ga2O3 to synthesize powders of the quaternary compound Zn2−x Sn1−x In x Ga x O4−δ in the stoichiometry of x = 0.2, 0.3, and 0.4 by solid state reaction at 1275 °C. Lattice parameters were determined by X-ray diffraction (XRD) technique and solubility of In3+ and Ga3+ in spinel Zn2SnO4 was found at 1275 °C. The solubility limit of In3+ and Ga3+ in Zn2SnO4 is found at below x = 0.4. The optical transmittance approximated by the UV–Vis reflectance spectra showed excellent characteristics while optical band gap was consistent across 3.2 eV with slight decrease along increasing x value. Carrier mobility of the species was considerably higher than the older versions of zinc stannate spinel co-substitutions whereas the carrier concentrations were moderate. [ABSTRACT FROM AUTHOR]

Published
2013
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