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Author

Sampat Raj Vadera

Other affiliations: Andhra University
Bio: Sampat Raj Vadera is an academic researcher from Indian Institute of Technology, Jodhpur. The author has contributed to research in topics: Nanoparticle & Ferrite (magnet). The author has an hindex of 26, co-authored 63 publications receiving 2242 citations. Previous affiliations of Sampat Raj Vadera include Andhra University.


Papers
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01 May 2012-Carbon
TL;DR: In this paper, reduced graphene oxide (RGO) with a layered and porous structure was synthesized by thermal exfoliation of graphite oxide using Fourier transform infrared and Raman spectroscopies, X-ray diffraction and scanning electron microscopy.

383 citations

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TL;DR: In this paper, a novel wet-chemical precipitation method is optimized for the synthesis of ZnS nanocrystals doped with Cu+ and halogen, and the nanoparticles were stabilized by capping with polyvinyl pyrrolidone (PVP).

219 citations

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TL;DR: In this paper, an alternate-current electroluminescent (ac EL) device based on doped ZnS nanocrystals emitting blue, green, and orange-red colors is reported.
Abstract: Alternate-current electroluminescent (ac EL) devices based on doped ZnS nanocrystals emitting blue, green, and orange-red colors are reported. ZnS nanocrystals doped with Cu+ – Al3+ and Cu+ – Al3+ – Mn2+ combinations were synthesized by wet chemical method at room temperature. The ZnS:Cu+, Al3+ nanocrystals show blue (462 nm) and green (530 nm) EL emissions depending upon the presence and absence of sulphur vacancies, respectively. The orange EL emission (590 nm) is realized from ZnS:Cu+, Al3+, Mn2+ nanoparticles by way of nonradiative energy transfer from AlZn – CuZn pairs to MnZn. The EL devices show low turn-on voltage of ~10 V ac @100 Hz. The mechanism of ac EL in ZnS nanocrystals has been explained wherein the excitation is attributed to the electric-field-assisted injection of electron-hole pairs from the surface regions into the interiors and their subsequent recombination therein causes emission.

128 citations

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TL;DR: In this paper, a single step method was developed for the preparation of graphene oxide/Fe2O3 composites by exfoliation of graphite oxide with an oxygen-rich ferric acetyl acetonate complex.

124 citations

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TL;DR: In this article, the authors reported electrical conductivity and dielectric studies on the composites of conducting polyaniline (PANI) with crystalline semiconducting ZnS powder, wherein PANI has been taken as inclusion and Zn S as the host matrix.
Abstract: In the present paper, we report electrical conductivity and dielectric studies on the composites of conducting polyaniline (PANI) with crystalline semiconducting ZnS powder, wherein PANI has been taken as inclusion and ZnS crystallites as the host matrix. From the studies, it has been observed that the value of room temperature d.c. conductivity of the composites with volume fraction of PANI > 0.65 shows an unusual behaviour wherein, conductivity values of the composites exceed that of PANI itself with maximum value as high as 6 times that of PANI at the volume fraction of 0.85. A similar trend has also been observed for the real and imaginary parts of complex dielectric constant values of the composites. This unusual behaviour in the d.c. conductivity and dielectric properties has been attributed to the enhancement in the degree of crystallinity of PANI as a consequence of its interfacial interaction with ZnS matrix. The results of optical microscopy show coating of PANI all around the ZnS particles. The temperature dependent conductivity studies suggest the quasi one-dimensional VRH conduction in PANI as well as its composites with ZnS. FTIR and XRD studies have also been reported.

117 citations


Cited by
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Journal ArticleDOI
18 Jul 2011-Small
TL;DR: The synthesis, characterization, properties, and applications of graphene-based materials are discussed and the promising properties together with the ease of processibility and functionalization make graphene- based materials ideal candidates for incorporation into a variety of functional materials.
Abstract: Graphene, a two-dimensional, single-layer sheet of sp(2) hybridized carbon atoms, has attracted tremendous attention and research interest, owing to its exceptional physical properties, such as high electronic conductivity, good thermal stability, and excellent mechanical strength. Other forms of graphene-related materials, including graphene oxide, reduced graphene oxide, and exfoliated graphite, have been reliably produced in large scale. The promising properties together with the ease of processibility and functionalization make graphene-based materials ideal candidates for incorporation into a variety of functional materials. Importantly, graphene and its derivatives have been explored in a wide range of applications, such as electronic and photonic devices, clean energy, and sensors. In this review, after a general introduction to graphene and its derivatives, the synthesis, characterization, properties, and applications of graphene-based materials are discussed.

2,246 citations

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1,682 citations

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TL;DR: The broadband and tunable high-performance microwave absorption properties of an ultralight and highly compressible graphene foam (GF) are investigated and it is shown that via physical compression, the microwave absorption performance can be tuned.
Abstract: The broadband and tunable high-performance microwave absorption properties of an ultralight and highly compressible graphene foam (GF) are investigated. Simply via physical compression, the microwave absorption performance can be tuned. The qualified bandwidth coverage of 93.8% (60.5 GHz/64.5 GHz) is achieved for the GF under 90% compressive strain (1.0 mm thickness). This mainly because of the 3D conductive network.

1,533 citations

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TL;DR: This review focuses on the recent development and various strategies in the preparation, microstructure, and magnetic properties of bare and surface functionalized iron oxide nanoparticles (IONPs); their corresponding biological application was also discussed.

1,143 citations

Journal ArticleDOI
TL;DR: In this paper, a comprehensive review of the state-of-the-art research activities related to ZnS nanostructures is provided, with the focus on the critical experiments determining the electrical, chemical and physical parameters of the nanostructure, and the interplay between synthetic conditions and nanoscale morphologies.

1,090 citations