Department Of Physics
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Item Role of sintering temperature in tailoring the electrical properties of 0.98KNNS�0.02BNZSH piezoelectric ceramics(Springer, 2023-02-16T00:00:00) Kumar, Amit; Kumari, Sapna; Kumar, V.; Kumar, Ashok; Goyal, P.K.; Aggarwal, Sanjeev; Arya, Anil; Sharma, A.L.Lead-free 0.98(K0.5Na0.5)(Nb0.96Sb0.04O3)�0.02(Bi0.5Na0.5)(Zr0.8Sn0.1Hf0.1)O3 (0.98KNNS�0.02BNZSH) perovskite ferroelectric ceramics have been designed and prepared through the traditional ceramic fabrication technique. To have an insight on the effects of sintering temperature (in the range from 1020 to 1110��C), the structural, microstructural, dielectric and ferro/piezoelectric properties of 0.98KNNS�0.02BNZSH ceramics are investigated systematically. The structural analysis has revealed a pure perovskite phase for sintering at different temperatures. The rhombohedral (R) and orthorhombic (O) phases coexist for sintering of 0.98KNNS�0.02BNZSH ceramic at 1080��C, while the rhombohedral phase dominates above 1080��C. The grains become more uniform and tightly packed when the sintering temperature is increased from 1020 to 1080��C. However, the grain size and the density have been revealed to be decreased for samples sintered above 1080��C. The conduction behavior of 0.98KNNS�0.02BNZSH ceramics has also been investigated using complex impedance spectroscopy. The optimum values of different dielectric and ferro/piezoelectric parameters for 0.98KNNS�0.02BNZSH ceramics sintered at 1080��C are obtained to be as the following: TC ~ 317��C, ?max ~ 7102, tan? ~ 0.10, ? ~ 4.49�g/cm3, d33 ~ 180 pC/N, and Pr ~ 16.7 �C/cm2. These findings show that crystallizability, density, and electrical properties are significantly influenced by the sintering temperature. � 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.Item MoSe2-FeOOH nanocomposite as hybrid electrode material for high-performance symmetric supercapacitor(Elsevier Ltd, 2022-12-29T00:00:00) Tanwar, Shweta; Arya, Anil; Sharma, A.L.Molybdenum diselenide-based composite has been considered a potential material in the supercapacitor application due to its variable oxidation states, high surface area, and electronic conductivity. This report presents the composite formation of molybdenum diselenide nanoflowers and iron oxide-hydroxide nanorods utilizing a hydrothermal route assisted by room temperature chemical blending technique. The symmetric cell designed based on prepared composite material delivers the specific capacitance of 132 F g?1 for 1 A g?1 for a 1 V voltage. It shows 100% capacitance retention for 3000 cycles and 100% coulombic efficiency for 10,000 cycles at 1 A g?1. It provides an energy density of 18.3 Wh kg?1 at 1174 W kg?1 power density. The practical application associated with the designed symmetric cell based on the composite electrode was confirmed via the illumination of the panel comprising 42 red LEDs for 10 min effortlessly without break. Additionally, a self-proposed charge mechanism has been incorporated for an enhanced understanding of the reader. The improved results indicate the point that the prepared electrode material has good capability for high-performance supercapacitors. � 2022Item Mesoporous carbon/titanium dioxide composite as an electrode for symmetric/asymmetric solid?state supercapacitors(Elsevier Ltd, 2022-08-27T00:00:00) Arya, Anil; Iqbal, Muzahir; Tanwar, Shweta; Sharma, Annu; Sharma, A.L.; Kumar, VijayThis paper reports the successful synthesis of mesoporous carbon/titanium dioxide (MC/TiO2) composite electrodes via the hydrothermal method for supercapacitor (SC) applications. The morphology and structural properties of MC/TiO2 composites were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectra (FTIR). The electrochemical properties were recorded by cyclic voltammetry (CV) and galvanostatic charge/discharge (GCD) with an electrolyte (6 M KOH) in symmetric/asymmetric configuration. The specific capacitance (Cs) evaluated by CV is about 280F/g for composite electrode (95 % capacitance retention after 1000 cycles) and pristine has 150F/g @ 10 mV/s. Enhancement in capacitance is owing to faster charge dynamics within electrode material. The fabricated asymmetric device demonstrates high energy density (30.31 Wh/kg), than the symmetric configuration (?27 Wh/kg). Finally, both symmetric/asymmetric supercapacitors have illuminated a red LED, and strengthens the candidature of composite electrode for energy storage technology. � 2022 Elsevier B.V.Item Synthesis, phase confirmation and electrical properties of (1 ? x)KNNS?xBNZSH lead-free ceramics(Springer, 2022-02-02T00:00:00) Kumar, Amit; Kumari, Sapna; Kumar, V.; Kumar, Prashant; Thakur, Vikas N.; Kumar, Ashok; Goyal, P.K.; Arya, Anil; Sharma, A.L.In the present work, lead-free piezoelectric ceramics (Rx)(K0.5Na0.5)(Nb0.96Sb0.04O3)?x(Bi0.5Na0.5)(Zr0.8Sn0.1Hf0.1)O3 [abb. as (Rx)KNNS?xBNZSH, 0 ? x ? 0.04] were prepared via solid-state sintering technique. The thermal behavior of mixed powders has been investigated for x = 0, 0.02, and 0.04 using TGA-DSC analysis to estimate the calcination temperature. The structural, morphological, dielectric, ferroelectric and piezoelectric properties are analyzed through the appropriate characterization techniques. The X-ray diffraction (XRD) patterns demonstrate a pure perovskite phase structure for all the sintered samples. Further, the coexistence of rhombohedral to orthorhombic (R-O) phase is observed in ceramic sample with x = 0.02. The morphology of all the sintered samples exhibits an inhomogeneous, dense microstructure with the rectangular grain, while for x = 0.02, a relatively homogeneous distribution of grains is observed. BNZSH doping decreases the average grain size from 2.22 to 0.33�?m for x = 0 to x = 0.04, respectively. Owing to the presence of multiple-phase coexistence as well as the improved microstructure and enhanced dielectric properties (dielectric constant ?r = 1080, ?max = 5301; Curie temperature - TC ~ 317��C; dielectric loss - tan? ~ 6%) the ceramics with x = 0.02 has been found to have a large piezoelectric coefficient (d33) of ~180 pC/N, remnant polarization (Pr) ~ 16.7 �C/cm2 and coercive field (Ec) ~ 10.7�kV/cm. We believe it will expand the range of applications for KNN-based ceramics. � 2022, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.Item Enhanced Curie temperature and superior temperature stability by site selected doping in BCZT based lead-free ceramics(Elsevier Ltd, 2022-01-31T00:00:00) Kumari, Sapna; Kumar, Amit; Kumar, Aman; Kumar, V.; Thakur, Vikas N.; Kumar, Ashok; Goyal, P.K.; Gaur, Anurag; Arya, Anil; Sharma, A.L.In this work, Bi3+ doped Ba0.98-3x/2BixCa0.02Zr0.02Ti0.976Cu0.008O3 [0 ? x ? 0.03] lead free ceramics, to be employed for structural, dielectric and ferroelectric studies, have been synthesized via conventional solid state reaction method. Rietveld refinement of the X-ray diffraction (XRD) data evidences the existence of a pure perovskite phase with tetragonal symmetry for all ceramics. The Scanning Electron Microscopy (SEM) reveals that the grain size, which is 16.14 ?m for x = 0 reduced to 2.11 ?m for x = 0.03. Dielectric studies demonstrate excellent dielectric behavior with high Curie temperature (TC ?159 �C), high dielectric constant (?r ?834, ?max ? 3146), and a low dielectric loss (tan? ? 0.019), for an optimum value of x = 0.02. The analysis of temperature coefficient of the dielectric permittivity indicates the applicability of these materials in multilayer ceramic capacitors. Impedance studies, conducted to understand the underlying physical mechanisms, are found to be in good agreement with the results of structural and dielectric studies. Furthermore, the ferroelectric measurement confirms the ferroelectric nature for all samples with an energy storage efficiency (?) of ?42% for x = 0.02 composition. � 2022 Elsevier Ltd and Techna Group S.r.l.Item High efficient carbon coated TiO2electrode for ultra-capacitor applications(IOP Publishing Ltd, 2021-10-08T00:00:00) Tanwar, Shweta; Arya, Anil; Singh, Nirbhay; Yadav, Bal Chandra; Kumar, Vijay; Rai, Atma; Sharma, A.L.The present paper reports the investigation of structural, optical, chemical bonding, and electrical properties of the carbon black (CB)/TiO2 composite synthesized via the standard sol-gel method. The structural and morphological properties have been investigated using x-ray diffraction and also field emission scanning electron microscopy to confirm the formation of the nanocomposite. The electrochemical performance of the two-electrode symmetric fabricated supercapacitor (SC) has been examined by complex impedance spectroscopy, cyclic voltammetry, and galvanostatic charge-discharge (GCD). The electrode CT15 (15% TiO2 in CB matrix) shows a high specific capacitance of 236 F g-1 at scan rate 10 mV s-1. The GCD illustrates good specific capacitance retention of 90.3% after 10 000 cycles and with energy density and power density values as 22 Wh kg-1 and 625 kW kg-1 respectively (at 1 A g-1) in the voltage window of 1.2 V. The CT15 electrode cell demonstrates superior electrochemical performance as compared to other electrodes. Electrochemical impedance spectroscopy (EIS) demonstrates the capacitive behaviour of the composite electrode with a low value of resistance. The SC cell having optimum performance has been chosen to demonstrate the glowing red light emitting diode. A mechanism has also been proposed based on received data parameters to validate the SC performance. � 2021 IOP Publishing Ltd.Item Fundamentals of Batteries and Supercapacitors: An Overview(CRC Press, 2021-09-06T00:00:00) Arya, Anil; Gaur, Anurag; Sharma, A.L.; Kumar, VijayEnergy plays an important role in daily human life and is the basic need in the present scenario. Nowadays, the development of energy sources is linked with the development of human civilization. The high energy density and high power density energy devices are on the radar of the research community. Batteries and supercapacitors (SCs) are two potential energy storage devices dominating the energy sector all over the world. This chapter starts with a focus on energy technologies and storage needs. Then, fundamentals of electrochemistry have been discussed followed by the working principle of battery and SC, and how energy is stored. Different types of batteries and SCs are discussed with their charge storage mechanisms. At last, important performance parameter and their influence on the overall device and its performance is presented. � 2022 Taylor & Francis Group, LLC.Item Role of energy loss-range profile of heavy ions in tailoring the optical properties of polycarbonate(Elsevier B.V., 2021-09-27T00:00:00) Chhokkar, Preeti; Kumar, V.; Goyal, Parveen K.; Kumar, Shyam; Tomar, A.K.; Gaur, Anurag; Arya, AnilPolycarbonate (PC) samples have been implanted with 115 keV N+, Ar+ and Kr+ at fluences ranging from 5x1014 to 1x1016 ions/cm2 to be employed for optical studies. A Decrease in optical energy gap, enhancement in reflectivity and reduction in transmittance, particularly in UV-region, is observed for all implanted samples. The change in optical properties of PC, first, by keeping energy deposited/cm2 constant (i.e. keeping energy*fluence constant) and then by keeping same depth of penetration for different ions have been analysed in detail. The changes are found to be more prominent for N+ compared to Ar+ and Kr+ when the fluence/energy deposited/cm2 by the ions is same. Further, the energy for N+ is reduced to 46 keV, while for Kr+ it is increased to 200 keV to ensure the same penetration depth for N+, Ar+ and Kr+ in PC. Finally, the results are explained on the basis of energy loss-range profiles of these ions in polycarbonate and through Raman spectroscopy. This study convincingly demonstrates that not only the types of ion species, their energies and fluences, but the total energy deposited by ions and their depth of penetration also plays an important role in tailoring the optical properties of polymeric materials. � 2021 Elsevier B.V.Item A comprehensive review on defect passivation and gradient energy alignment strategies for highly efficient perovskite solar cells(IOP Publishing Ltd, 2021-10-07T00:00:00) Saykar, Nilesh G.; Arya, Anil; Mahapatra, S.K.Recent advances in photovoltaic devices demonstrate a potential candidature of the lead halide perovskite solar cells (PSCs) to fulfill the all-electric future of the world. Further improvements in efficiency and stability require minimization of non-radiative recombination arising due to the tr ap states created by the vacancies and defects. The device's performance is mostly determined by the perovskite absorber material, which has single-cation, mixed-cation, and/or mixed-halide composition-dependent optoelectronic capabilities. Herein, we present an insight on the state of the art of PSCs, including types of defects, their effects, and remedies of the same. Various design strategies administered to grow highly crystalline perovskite films with low defects at interfaces are described in detail. The inclusion of a few nm thin interlayer between perovskite and charge transport layer (CTL) is an effective way to passivate the defect at the interface. Furthermore, additive engineering is emerging as an excellent strategy to grow the defect-free perovskite by simply adding a polymer, ionic liquids, organic/inorganic salts in precursor solution without precipitating after film formation. The mitigation of charge recombination could be achieved by efficient charge extraction through proper energy alignment of CTLs and absorbers. Notably, we emphasize the interface, additive, and gradient band alignment engineering and resulting improvement in the photocurrent density, photovoltage, power conversion efficiency, and long-term stability. The present review gives complete information about PSCs, starting from the selection of the materials to PSC fabrication, charge carrier dynamics, defects, effects, and remedies. We hope that this summarised information will give a basic understanding of designing new passivation strategies for advancing PSC's present state of the art. � 2021 IOP Publishing Ltd.Item Energy Storage and Conversion Devices: Supercapacitors, Batteries, and Hydroelectric Cells(CRC Press, 2021-09-06T00:00:00) Gaur, Anurag; Sharma, A.L.; Arya, AnilThis book presents a state-of-the-art overview of the research and development in designing electrode and electrolyte materials for Li-ion batteries and supercapacitors. Further, green energy production via the water splitting approach by the hydroelectric cell is also explored. Features include: � Provides details on the latest trends in design and optimization of electrode and electrolyte materials with key focus on enhancement of energy storage and conversion device performance � Focuses on existing nanostructured electrodes and polymer electrolytes for device fabrication, as well as new promising research routes toward the development of new materials for improving device performance � Features a dedicated chapter that explores electricity generation by dissociating water through hydroelectric cells, which are a nontoxic and green source of energy production � Describes challenges and offers a vision for next-generation devices This book is beneficial for advanced students and professionals working in energy storage across the disciplines of physics, materials science, chemistry, and chemical engineering. It is also a valuable reference for manufacturers of electrode/electrolyte materials for energy storage devices and hydroelectric cells. � 2022 Taylor & Francis Group, LLC.