Browsing by Author "Sahoo, Sumanta Kumar"

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A Perspective on Recent Advances in 2D Stanene Nanosheets
(1970-01-01)
Sahoo, Sumanta Kumar
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Wei, Kung-Hwa
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交大名義發表
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National Chiao Tung University
Advancements in 2D nanomaterials have been impacting a wide range of technology-driven applications. Here, the authors highlight stanene, a material that comprises a monolayer of elemental tin atoms, as a new addition to the monoelemental 2D family. Recent successes in the experimental realization of stanene in supported heterostructures and in free-standing form have expanded interest in exploring and unlocking its potential applications, as predicted from advanced theoretical calculations. Stanene exhibits several remarkable features, including a large spin-orbit gap (allowing room-temperature electronics based on the quantum spin Hall effect), topological superconductivity, quantum anomalous Hall behavior, giant magnetoresistance, and efficient thermoelectricity. Research into stanene and stanene-based 2D materials, both experimentally and theoretically, is suggesting immense potential for future quantum-based electronics systems. Here, the fundamental features of stanene, progress in its synthesis, and future perspectives are discussed.
Cathodic plasma-induced syntheses of graphene nanosheet/MnO2/WO3 architectures and their use in supercapacitors
(2020-05-10)
Huang, Shih-Yu
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Phuoc-Anh Le
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Yen, Po-Jen
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Lu, Yi-Chun
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Sahoo, Sumanta Kumar
In this study, we synthesized new 0.01-2 mu m graphene nanosheet/MnO2WO3(G/MnO2/WO3) architectures through an electrochemically induced cathodic plasma process in a single batch at a lower temperature (70 degrees C) and for a shorter time (2 h) than those required for the syntheses of similar structures when using a hydrothermal method. We first obtained 0.01-1 mu m leaf-like graphene (G) nanosheets, then 0.1-0.3 mu m long and approximately 10 nm diameter petiole-like MnO2 nanowires on the G nanosheets, and finally 0.20-2.0 mu m petal-like WO3 on MnO2/G - thereby forming the G/MnO2/WO3 architectures - as evidenced using scanning electron microscopy and transmission electron microscopy. We deciphered the step-wise reaction mechanism behind the formation of the G/MnO2/WO3 architectures during the plasma process. The high surface area of 291 m(2) g(-1) in the G/MnO2/WO3 architecture was contributed mainly by the G nanosheets, providing a suitable surface area for diffusion of the charge carriers during the charging and discharging process. As a result, an electrode incorporating the G/MnO2/WO3 architectures exhibited an excellent specific capacitance of 620 F g(-1) - 45 and 200% higher than those of G/MnO2 (421 F g(-1)) and G (189 F g(-1)) electrodes, respectively - at a current density of 0.5 A g(-1). Moreover, the G/MnO2/WO3-incorporated electrode exhibited good electrochemical cycling stability, with 90% capacitance retention over 5000 cycles at 1 A g(-1). Such new G/MnO2/WO3 heterojunction structures, not only provide high-performance electrode applications, but also suggest a potential approach toward fabricating other heterojunction structures having high surface areas for energy storage applications. (C) 2020 Elsevier Ltd. All rights reserved.
Fundamentals of Fascinating Graphene Nanosheets: A Comprehensive Study
(2019-03-01)
Sahoo, Sumanta Kumar
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Mallik, Archana
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材料科學與工程學系
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Department of Materials Science and Engineering
Graphene nanosheets have attracted immense research interest among the materials science community from electronics to the biomedical field. Being the first member of two-dimensional nanomaterials family, discovered in 2004 followed by the Nobel Prize winning in 2010, it is now readily witnessing global industrial revolutions. The nanomaterial is bestowed with such unprecedented features that can be tangible to a wide spectrum of applications ranging from energy storage devices to sensor application. Enormous flattened surfaces, superior mechanical strength and flexibility, ballistic intrinsic carrier mobility, nearly transparent nature, high thermal conductivity and room-temperature ferromagnetic behavior are few of the extraordinary attributes of the monolayer of carbon nanosheets. In this comprehensive review, an attempt has been put forward to precisely revisit and represent the literature available on the fundamental properties of graphene nanomaterials. Also, the usage of its characteristic features in various applications as well as synthesis process has been briefly discussed.
Using Different Ions to Tune Graphene Stack Structures from Sheet- to Onion-Like During Plasma Exfoliation, with Supercapacitor Applications
(2019-04-23)
Yen, Po-Jen
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Sahoo, Sumanta Kumar
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Chiang, Ya-Chi
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Huang, Shih-Yu
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Wu, Chia-Wei
In this article, we report a facile and simple approach for tuning graphene nanosheet structures (GNS) with different ions in the electrolytes through cathodic plasma exfoliation process in electrochemical reactions. We obtained sheet- and onion-like GNS when aqueous electrolyte NaOH and H2SO4, respectively, were present during plasma exfoliation in the electrochemical reactions, as evidenced from scanning electron microscopy and transmission electron microscopy images. Moreover, the onion-like GNS exhibited a specific surface area of 464m(2) g(-1) and a supercapacitive performance of 67.1F g(-1), measured at a scan rate of 5mV s(-1) in 1M NaCl; these values were much higher than those (72m(2) g(-1) and 21.6F g(-1), respectively) of the sheet-like GNS. This new approach for efficiently generating tunable stacked graphene structures with different ions, in the cathodic plasma exfoliation process, has promising potentials for use in energy storage devices.