Browsing by Author "Alegaonkar, Prashant S."

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Blast mitigation properties of porous nano-carbon
(Elsevier Ltd, 2021-11-03T00:00:00) Chinke, Shamal L.; Sandhu, Inderpal S.; Alegaonkar, Prashant S.
Designing and development of a superior shock mitigation nano�material shield is an emerging armour building technology. We report, the effect of Kolsky bar simulated blast waves, onto the shock damping characteristics of the porous nano�carbon (abbreviation: PNC), synthesized by pyrolysis of biomass precursor. Measurement of stress (?)�strain (?), constitutive variables reveal the elasto�plastic behaviour suggesting moderate built�up, and accumulation of stress; independent of applied strain before reaching a yield ~50 MPa. Gruneisen fatigue parameter is estimated to be less (~0.92) over a theoretical Rayleigh limit with >80% post impact damage of porous component. The loci of dictated shock states derived from Rankine�Hugoniot formulism demonstrates the hydrodynamic interplay between pressure (P), volume (V), shock (US) and particle (UP) velocity. For PNC, Rayleigh slope is observed to be reduced, whereas, US became pressure independent over 10 GPa. Behaviour of P�UP hydrodynamic equation displays 30% variation in shock states and predicts a reduction of sound speed by a factor of ~0.25 in porous matrix. Behind the shock wavefront, matrix particles attend a max�speed of 100 km�s?1. The value of elastic limit for PNC is ~8.62 GPa as obtained by analysing the actual shock profile, with an evidence of phase transformation. Electron and force microscopy studies show reduction in an area, effectively, by 20�30%, thickness by six�fold factors with a rise in topological disorder. Hydro�physical variables inferred from Raman, scanning electron, transmission electron, and atomic force microscopy is comparatively discussed for PNC and other nano�carbons. Shock topology obtained by pressure�time signal processing shows ~30% impact of the shock onto PNC and manifested as shock echo. Details of the analysis are presented. � 2021 Elsevier B.V.
Design and Manufacturing of a Hexapattern Frequency Selective Surface Absorber for Aerospace Stealth Application
(American Chemical Society, 2023-07-21T00:00:00) Priyanka, None; Mohanty, Subrat; Alegaonkar, Prashant S.; Baskey, Himangshu B.
Integrated frequency selective surface (IFSS) absorbers with larger bandwidth, effective reflection loss, polarization-insensitive characteristics, angular stability with compact/thin design, and ease of fabrication have captivated significant importance in stealth technology. Herein, we report on an IFSS absorber that has been designed, simulated, and implemented for manufacturing to achieve effective stealth properties. Initially, frequency selective surface (FSS) layers have been designed that comprise a closed centroid honeycomb structure surrounded with four annular hexagonal rings, splitted, alternatively, and enveloped with four L-shaped elements. The simulated pattern has been optimized on glass fabric for reflection loss (RC, dB) at a thickness of ?0.1 mm by choosing sheet resistance of pattern 110 ?/?. A FSS layer combined with interlayer lossy dielectric laminates (1.8 mm) and a carbon-fabric-reinforced-plastic ground has been simulated as an IFSS absorber. The performance of RC, in normal and angular configuration (0-60�), under transvers an electric/magnetic mode of polarization, including analysis of the displacement current, volume power loss distribution, and complex admittance has been carried on IFSS. Subsequently, the proposed absorber has been fabricated using customized carbon-based resistive ink imprinted on glass fabric by mask lithography compounded with laminates (a carbon black powder/epoxy composite) and ground. Their manufacturing details, including free space and anechoic chamber RC measurements, have been presented. The simulated and experimental RC performances of the absorber are found to be in good agreement, possessing minimal 10 dB reflection loss (90% absorption) with a sample thickness of 1.9 mm (0.05?L, where ?L corresponds to a lower operating frequency), covering 76% fractional bandwidth in X and Ku bands. The proposed design architecture of the IFSS is ideally suitable for aerospace stealth platforms. � 2023 American Chemical Society.
Electrical Conductivity of MXenes-Based Polymer Composites
(CRC Press, 2023-04-07T00:00:00) Biswas, Sayani; Alegaonkar, Prashant S.
MXenes are a new addition to the interesting class of 2D materials, and are a work in progress. There is a wide range of combinations and exciting properties associated with MXenes; one of them is their tendency to form polymer nanocomposites with enhanced features. Polymers and MXenes, when blended together, form a cohesive system in which the best properties of both the constituents are featured while the drawbacks are compensated. When MXenes are paired with conducting polymers, the resultant conductivity achieved surpasses the values produced individually. In this study, the electrically conductive nanocomposites of MXene and polymer are described, highlighting the most significant and recent works. These works are the stepping stones for future experiments of MXene-polymer composites to perfect their characteristics, conductivity and other electronic properties. � 2023 selection and editorial matter, Poushali Das, Andreas Rosenkranz, and Sayan Ganguly; individual chapters, the contributors.
High Speed Projectile Sensor: Design, Development and System Engineering
(Institute of Electrical and Electronics Engineers Inc., 2021-10-15T00:00:00) Chinke, Shamal L.; Berhe, Solomon; Alegaonkar, Prashant S.
Chronography is a muzzle velocity and position sensor for a small metallic projectile (bullet) used for the military training purpose. We report on design, development, and performance testing of a conductor-insulator-conductor (CIC) sensory panel integrated with chronograph hardware and portable bullet speedometer. The established system is capable of dual recharging by alternating current mains as well as by battery support. The sensory mechanism is based on a short circuit voltage pulse developed while onset passage of the bullet from the screens. The pulse time is suitably registered, transferred, and communicated to a data storage unit interfaced to a multiport readout using the developed hardware. The whole sensor circuitry was, initially, simulated followed by optimization and final assembly of the hardware. Moreover, measured read out is taken onto a handheld speedometer with a capability to connect to personnel computer/laptop or cell phone using a state-of-the-art wireless fidelity communication interface. Three-dimensional printing technology was used to package the integrated sensor, after finalizing isometric engineering drawings. Details of fabrication, integration, and performance evaluation is demonstrated. System is real time, portable, power, and cost effective. Sensor is capable to measure the muzzle velocity 1000 m/s more than 98% accuracy when compared with a standard doppler radar and an acoustic sensor. Details are presented. � 2001-2012 IEEE.
High-performance and ultra-sensitive ultraviolet photodetector based on surface passivated ?-Fe2O3 thin film
(Elsevier Ltd, 2023-03-01T00:00:00) Kaawash, Nabeel M.S.; Halge, Devidas I.; Narwade, Vijaykiran N.; Alegaonkar, Prashant S.; Bogle, Kashinath A.
Nanostructured ?-Fe2O3 is a versatile material and has attracted extensive attention due to its promising electrochemical and photoelectrochemical properties, which are widely investigated in water splitting, photoelectrochemical devices, gas sensors, and catalysis. Moreover, its band gap (Eg = 2.0 eV) allows it to absorb visible light, but due to poor charge carrier mobility, ultrafast recombination of the photo-generated carriers, and surface oxygen vacancy defects its application as a photodetector got restricted. Herein with a surface passivated ?-Fe2O3 film deposited on the glass substrate, the ultraviolet photodetector is demonstrated. The surface passivated photodetector is sensitive to ultraviolet light, showing a substantial enhancement in the photo-responsivity of 1.41 A/W, the external quantum efficiency of 515%, the photo-sensitivity of 1650%, and a reduction in response time of 0.06 ms (for 340 nm at a bias of +30 V) as compared with the device before surface passivation (0.228 A/W, 83%, 34%, and 1.6 ms), respectively. These improved properties are observed due to the suppression of surface defects via surface passivation, which increases free carrier concentration transport across the film. The surface passivated ?-Fe2O3 thin film-based photodetector with high photo-responsivity, photo-sensitivity, high speed, and ultraviolet photoresponse is promising for practical applications, and this platform opens up new avenues for the development of low-cost, and highly efficient ultraviolet photodetectors. � 2023 Elsevier B.V.
High-performance supercapacitor based on MoS2@TiO2 composite for wide range temperature application
(Elsevier Ltd, 2021-06-07T00:00:00) Iqbal, Muzahir; Saykar, Nilesh G.; Arya, Anil; Banerjee, Indrani; Alegaonkar, Prashant S.; Mahapatra, S.K.
Transition metal sulphide and their composites gain attention as electrode material in energy storage devices due to their superior properties like excellent conductivity, high surface area, and porosity. We report an evaluation of the electrochemical performance of MoS2@TiO2 binary composite in symmetric supercapacitor assembly at different temperatures. A facile hydrothermal technique is used to prepare MoS2@TiO2 binary composite. Structural and morphological analysis reveals that highly crystalline composite comprising MoS2 assembled in flower-like flake configuration, whereas, TiO2 in nanorods form are prepared. Among all three electrodes, MoS2@15%TiO2 demonstrates maximum specific capacitance 210 F/g at 10 mV/s with excellent cycling stability (98%, 2000 cycles) at ambient temperature. It may be concluded that the mono-phased, mesoporous structure is a key feature behind the improved performance over the other electrodes. Further, improvement in charge-discharge characteristics has been observed by a factor of 200% at 60 �C attributing to low activation energy and faster ion dynamics at elevated temperatures. The impedance spectroscopic analysis reveals a significant reduction in interfacial impedances that leads to a superior capacitance effect compounded with favourable electrolytic charge dynamics. The highest energy density is reported to be 21 Wh/kg with a power density of 1300 W/kg in symmetric configuration. Synergistic effect of the binary system along with unique surface morphology and charge storage followed by intercalation and capacitive mechanism results in enhanced performance of supercapacitor with MoS2@15%TiO2. Thus, binary MoS2@TiO2 composite seems to be an exceptional candidate for the energy storage device operating at a wide temperature range (25�60 �C). � 2021 Elsevier B.V.
Highly stable and sensitive photon detection performance of ZnO thin film for ultraviolet light
(Elsevier B.V., 2022-04-14T00:00:00) Kaawash, Nabeel M.S.; Kejriwal, Nubbh; Halge, Devidas I.; Narwade, Vijaykiran N.; Rana, Abhimanyu S.; Dadge, Jagdish W.; Jejurikar, Suhas M.; Alegaonkar, Prashant S.; Bogle, Kashinath A.
The photo detection characteristics of spray pyrolysis deposited ZnO thin film on glass substrate at 250 OC was demonstrated for fabrication of highly stable visible-blind UV photodetector. This photodetector exhibits lower dark current < 0.04 ?A, higher UV photosensitivity ?4750, responsivity of 0.14 A/W and detectivity of 1.24 � 1012 Jones at an average intensity of 140 ?W/cm2 of 340 nm. This Ag/ZnO/Ag device show excellent photo response (rise and decay) time of ?4 and 6 ms with external quantum efficiency of 51%. The observed photocurrent in the device is associated with adsorption and light-induced desorption of oxygen from the defect sites on the film surfaces. The adsorbed oxygen removes the electron trap centers and increasing the free carrier density in ZnO. � 2022 Elsevier B.V.
Microwave scattering behaviour of carbon black/ molybdenum di sulphide /cobalt composite for electromagnetic interference shielding application
(Elsevier Ltd, 2022-01-28T00:00:00) Yadav, Akshita; Tripathi, Krishna C.; Baskey, Himangshu B.; Alegaonkar, Prashant S.
Erasing signature of an object from an enemy's radar is, tactically, disruptive move achieved by the effective electromagnetic interference (EMI) shield. We report on the microwave scattering (2�18 GHz) behaviour of the nano-composite for architecting efficient shield composed of carbon black (CB), molybdenum di sulphide (MoS2) and cobalt (Co). Nano-composite, prepared by a facile, solid state synthesis route, are characterized using infrared, x-ray diffractometry, UV�visible, energy dispersive x-ray spectroscopic techniques including scanning electron microscopy. In infrared and Rayleigh analysis, formation of -C-Mo-C, O[dbnd]S[dbnd]O, Mo�O, and Co�O phases generated asymmetric polarization at low % CB content that gets transformed into a symmetric mode due to formation of Co�O and Co�S�C radicals at high CB % to cause maximum power losses. Possible polarization mechanism is discussed. In constitutive analysis, two-fold increase in the dielectric function, the dual behaviour (Debye and Jonscher) of the ac conductivity, and the synergistic magneto-dielectric coupling factor influenced the scattering performance of the composite. Broadly, at 18% composition, the shielding effectiveness is recorded to be > 97@14 GHz with 7.7 GHz of the bandwidth and the thickness ?2.5 mm. The Dallenbach return loss is almost 75% revealing a high-performance shield design @18% CB/MoS2/Co nano-composite. � 2022 Elsevier B.V.
Microwave scattering parameters of ferro-nanocarbon composites for tracking range countermeasures
(Royal Society of Chemistry, 2021-12-18T00:00:00) Alegaonkar, Ashwini P.; Baskey, Himangshu B.; Alegaonkar, Prashant S.
In the strategic sector, frequently, the radar signatures in the microwave frequency region are cluttered, which can be overcome by designing and developing an effective electromagnetic interference (EMI) shield. Herein, we report the analysis of the s-parameter performance of ferro-nanocarbon (FNC) composites tested over the frequency region of 8-12 GHz (X-band). The FNC composite was prepared via a simple, single-pot, solid-state sublimation route with different contents of iron (1-4%). The fabricated material was characterised using X-ray diffractometry, scanning electron microscopy, vibrating sample magnetometry and several spectroscopic techniques such as infrared, UV-visible, and energy dispersive X-ray analysis. S-parameter and reflection loss studies were performed by transforming the composite material into a coaxial- and rectangular-shaped specimen, respectively. In the analysis, the inclusion of iron resulted in the formation of crystalline Fe2O3 (d[110]) and Fe3O4 (d[220]) phases, which were self-dispersed in the nanocarbon structure. The inclusion of iron was responsible for creating an asymmetric bond molecular environment in C-O-Fe, resulting in synergistic magneto-dielectric effects in terms of long-range polarization ordering mainly through the transitions between the O-2p and Fe-3d states to engage the incoming microwave field effectively. This composite showed a good performance of >98% shielding effectiveness with an infinite bandwidth and >99% return loss at a matching frequency of 9.01 GHz. This journal is � The Royal Society of Chemistry.
Mitigation in broad band microwave shielding properties of Ni-Co/NC composite
(Elsevier Ltd, 2023-02-09T00:00:00) Sahoo, Suprava; Tripathi, Krishna C.; Baskey, Himangshu; Alegaonkar, Prashant S.
It is tactically important for a high-resolution seeking tracker to generate clutter, greatly facilitated by electromagnetic interference shielding. Nickel-Cobalt /Nano?carbon (Ni-Co/NC) composites are synthesized by a simple, solid-state combustion method. The scattering performance of Ni-Co/NC composites is reported over the frequency range of 2�18 GHz with varying equal weight % of Nickel and Cobalt from (5 to 25)% and characterized using X-ray diffraction, Fourier transform-infrared spectroscopy, Energy Dispersive X-ray spectroscopy, and Scanning Electron Microscope technique. Additionally, fabricated toroidal specimens are examined for reflection loss measurements. According to analysis, the phases NiO and NiCo2O4 are formed when nickel and cobalt are added to nano?carbon. These phases subsequently diffuse throughout the nano?carbon network to produce the Ni�O stretching vibration modes, O-X-O and X-O-X (where X = Ni or Co) modes. Asymmetric polarization at low nickel?cobalt weight % changes to symmetric polarization at higher weight % in the Ni-Co/NC composites. The analysis of constitutive parameters indicated a hybrid ac conductivity behaviour (Debye- and Jonscher-like), an increase in complex permittivity and permeability, and a variation in synergetic magneto-dielectric coupling energy with frequency. Additionally, the characteristic impedance and skin resistance have been calculated. In general, the 20-wt% Ni-Co/NC composite exhibits the highest absorption at 7.28 GHz at 3.85 mm of thickness at low frequency. However, over a higher frequency range, the 5-wt% Ni-Co/NC composite exhibits a high-performance shield design, achieving ?21.05 dB reflection loss at a thickness of 5.45 mm with 2.24 GHz of effective bandwidth. � 2023 Elsevier B.V.
MXene: Evolutions in Chemical Synthesis and Recent Advances in Applications
(Multidisciplinary Digital Publishing Institute (MDPI), 2021-12-23T00:00:00) Biswas, Sayani; Alegaonkar, Prashant S.
Two-dimensional materials have secured a novel area of research in material science after the emergence of graphene. Now, a new family of 2D material-MXene is gradually growing and making itsmark in this field of study. MXenes since 2011 have been synthesized and experimented on in several ways.The HF treatment although successful poses some serious problems that gradually propelled the ideas of new synthesis methods. This review of the literature covers the major breakthroughs of MXene from the year of its discovery to recent endeavors, highlighting how the synthesis mechanisms have been developed over the years and also the importance of good characterization of data. Results and properties of this class of materials arealso briefly discussed alongwith recent advance in applications. � 2021 by the authors.
Polarization-independent enhancement in UV photoconductivity of BiFeO3/Sn:In2O3 heterostructure
(Elsevier B.V., 2023-05-08T00:00:00) Banda, Rajender Reddy; Halge, Devidas I.; Narwade, Vijaykiran N.; Kaawash, Nabeel M.S.; Thabit, Mohammed Y.H.; Alegaonkar, Prashant S.; Bogle, Kashinath A.
Currently, polarization-dependent transport in ferroelectric materials under optical illumination is gaining a lot of attention in optoelectronics. This idea is implemented on BiFeO3 to illustrate its UV�Visible light photodetection property, however, naturally occurring bismuth or oxygen vacancies serve a major disadvantage as they interfere with its polarization ability. It is very difficult to overcome this defect issue in bismuth-based perovskites, therefore, based on this herein an enhancement in the photoconductive property of polycrystalline BiFeO3 thin film deposited via spray pyrolysis technique on Sn:In2O3 coated glass substrate is demonstrated without polarizing it. An extraordinary photodetection behavior with higher photoresponsivity (1.01 A/W) and external quantum efficiency (364) as well as faster response speed (6 ms) even under low UV illumination (340 nm) and lower applied bias of 2 V is observed. The roles of the BiFeO3�Sn:In2O3 interface, as well as the adsorption/desorption of oxygen molecules on the surface of BiFeO3 layers, were highlighted for the ferroelectric material's UV photodetector application. � 2023 Elsevier B.V.
Preparation and Energy Storage Assessment of Ti3C2 2d MXene and Its Possible Thinning Mechanism
(Springer Nature, 2023-09-07T00:00:00) Singh, Diya; Rani, Pinki; Biswas, Sayani; Alegaonkar, Prashant S.
Since after its discovery, MXene has captivated the focus of many researchers. In this work, we report on the low-temperature synthesis of Ti3AlC2 MAX phase at 800�? and its further etching to obtain Ti3C2 MXene. Initially, titanium (Ti), aluminium (Al), and graphite (C) precursors were taken in an appropriate volume proportion and add-mixed and grounded well via molten salt technique (Galvin et al. in J Eur Ceram Soc 38, 2018 [1]). The characterizations performed on powder such as FTIR, XRD, UV�Visible, SEM, and EDS confirmed Ti3AlC2 MAX phase. The MAX phase was subjected to the acid treatment (HF, concentration 40%) for ~ 80�h. The synthesized MXene was separated and investigated using FTIR, XRD, UV�Visible, SEM, and EDS techniques. The MXene was further employed to microwave treatment over the temperature 300�420�K at a discharge of power 120 W for 1�h. Analysis revealed that thickness of Ti3C2 layers is observed to be decreased with microwave treatment which can be a possible mechanism to obtain MXene quantum dots. In electrochemical analysis, specific capacitance for two electrode MXene@300�K and @400�K is reported to be 15 and 10�F/g, respectively, showing resistive nature of capacitance coupling for MXene. Analysis of electrochemical impedance spectroscopy together with bode showed the surface passivation effect of MXene layers to achieve different charge dynamics in both the systems. � 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
Rationally designed state-of-the-art approach for enhancing the ultraviolet photon detection performance of ZnO thin film
(Elsevier B.V., 2022-10-07T00:00:00) Kaawash, Nabeel M.S.; Halge, Devidas I.; Narwade, Vijaykiran N.; Alegaonkar, Prashant S.; Bogle, Kashinath A.
Here, we demonstrate a simple and effective state-of-the-art (surface passivation) approach for enhancing the UV photo detection performance of ZnO thin films synthesized via spray pyrolysis. The surface passivated Ag/ZnO/Ag device (using polyvinyl alcohol layer) has low dark current of 1.1 nA as compared with the device without surface passivation (0.04 ?A). The significant decay in the dark current after surface passivation is due the reduction in the density of surface oxygen vacancies confirmed by PL measurements. The UV photon detection capability of the surface passivated ZnO thin film exhibits a significantly high photo response (3675), high photosensitivity (3.6 � 105), photo-responsivity (0.6 A/W) and fast response time (0.6 ms) under UV light (340 nm, 140 ?W/cm2). This straightforward approach superimposes surface defects, making the ZnO thin film more suitable for a wide range of electronic device applications while preserving the material's intrinsic properties. � 2022 Elsevier B.V.
Reduced graphene oxide doped tellurium nanotubes for high performance supercapacitor
(Frontiers Media S.A., 2022-10-20T00:00:00) Rani, Pinki; Alegaonkar, Ashwini P.; Biswas, Rathindranath; Jewariya, Yogesh; Kanta Haldar, Krishna; Alegaonkar, Prashant S.
Supercapacitors have been achieving great interest in energy storage systems for the past couple of decades. Such devices with superior performance, mainly, depending on the material architecture of the electrodes. We report on the preparation of Tellurium nanotubes (Te-tubes diameter ?100�nm and length ?700�nm), with variable doping of conducting network reduced graphene oxide (rGO) to fabricate high-performance electrode characteristics of rGO @ Te. The prepared material was characterized using XRD, FTIR, FESEM, and Raman spectroscopy techniques, including Brunauer-Emmett-Teller, Barrett-Joyner-Halenda measurements. FTIR study revealed that 15% rGO @ Te has a wide C-O vibration band at ? 1,100�1,300�cm?1, over other compositions. FESEM study shows the Te-tubes dispersion in rGO layers. The EDX study revealed that 15% of the composition has an optimistic concentration of C and O elements. In other compositions, either at lower/higher rGO concentration, an uneven count of C and O is observed. These support efficient charge dynamics to achieve superior ultra-capacitor characteristics, thereby achieving specific capacitance Csp 170 + F/g @ 10�mV/s in a symmetric configuration. The reported values are thirty times higher than pristine Te-tubes (?5�F/g). This finding suggests that rGO @ Te is a promising candidate for supercapacitor. Copyright � 2022 Rani, Alegaonkar, Biswas, Jewariya, Kanta Haldar and Alegaonkar.
Shock wave hydrodynamics of nano-carbons
(Elsevier Ltd, 2021-02-02T00:00:00) Chinke, Shamal L.; Sandhu, Inperpal S.; Bhave, Tejashree M.; Alegaonkar, Prashant S.
Dynamic deformation of nano-carbons by shock waves is an important object in technological applications as well as in basic sciences. We report, on hydrodynamic response of two types of nano-carbon systems: graphene nano-flakes (GNF) and carbon nano-spheres (CNS) by subjecting them to the Klosky bar shock test (at strain rate 102�104/s). Data of stress (?), strain (?), and strain rate (?) were obtained with time to analyse the behaviour of constitutive parameter (?�?). In elastic region GNF showed superior stress sensitivity at least by fivefold over CNS, whereas, stress accumulation ability of CNS was found to be ten times better than GNF. In plastic region both the systems were behaved quiet complexly. They comprised of various stages of deformation like inter�particle separation, micro�structure gliding, fracture, and perforation. To obtain hydrodynamic variables a few thermodynamic assumptions like matrix homogeneity, linear volume deformity, negligible temperature rise were made to set up the Lagrange�Rankine�Hugoniot model. Interplay of built�in pressure (P), particle velocity (UP), shock velocity (US), specific volume (V/VO), density (?), shock energy (E), behind and ahead of the shock wavefront led to the establishment of the equation of state for the system. Theoretical shock profile was vis-�-vis compared with the experimentally obtained shock results. Distribution of impulse pressure over the topology of the nano-carbons was examined that exhibited non-uniform shock energy dissipation pattern with peak pressure ~250 N/m2. Our calculations revealed that, almost ~65% shock energy was damped within GNF and ~89% in CNS. Details of the analysis are presented. � 2021 Elsevier B.V.
Simple and Productive Method to Develop Highly Sensitive and Fast Infrared Photodetector Using Spray Deposited Nanocrystalline PbS Thin Film
(Institute of Physics, 2023-02-16T00:00:00) Thabit, Mohammed Y. H.; Kaawash, Nabeel M. S.; Begum, Sumayya; Halge, Devidas I.; Narwade, Vijaykiran N.; Alegaonkar, Prashant S.; Bogle, Kashinath A.
This work demonstrates the development of a highly sensitive and fast infrared photodetector using a PbS thin film deposited using a simple and scalable method known as "spray pyrolysis". An aqueous precursor solution was deposited on a glass substrate at 150 �C have a cubic phase of PbS. Silver electrodes with a 1 mm gap are drawn on the film to create photo-detector devices. Low resistive contact between the silver electrode and the PbS film is revealed from the linear I-V measurements performed in the dark and under light illumination. Under the illumination of a 100-watt tungsten lamp, the photo-responsivity, sensitivity, response time, and decay time of the PbS film were measured. The Ag/PbS/Ag photodetector device has a responsivity of 70 mA/W, a sensitivity of 200 at 30 V, and the best response and decay times of 6.4 and 15.6 ms, respectively. The photodetector device produced by this simple and low-cost fabrication method has a fast response and decay time. � Published under licence by IOP Publishing Ltd.
Synergistic photophysical and electrochemical response of Te @ PANI for energy harvesting
(Springer, 2023-01-07T00:00:00) Rani, Pinki; Jewariya, Yogesh; Haldar, Krishna Kanta; Biswas, Rathindranath; Alegaonkar, Prashant S.
Materials with synergistic functionality are of great importance in consumer electronics. We report on the preparation and assessments of Te @ PANI composite for energy conversion and storage application. Initially, (5�15%) Te @ PANI composites were synthesized by the facile, room temperature, time and cost-effective solid-state synthesis technique followed by characterizations using Fourier transform infra-red, UV-Visible, energy dispersive spectroscopic including X-ray diffractometry and field electron scanning microscopy. Te exfoliates polymeric segments of PANI by bonding benzenoid rings through sulphonated impurity sites which have a profound impact on symmetry molecular bond vibrations. Its analysis is presented. In photophysical application, both dark and luminescent I-V measurements have been performed that showed a linear variation with minimum photo-resistance offered by 10% composite and reaching current > 10�mA under 1.5�V biased conditions. In storage response, Te @ PANI supercapacitor devices are dominating in inductive coupling over capacitive coupling by ten times. Corresponding shunt impedance is seen to be favourably lower for 10% composition, and respective charge transfer impedance has also followed identical behaviour over other classes of samples. The quality factor of the device for 10% is found to be almost twelve times better. However, at a low scan rate (10�mV/s), the presence of Te has changed the tendency of ion migration, thereby, reducing the magnitude of ion current by about three times with an increase in Te from 5 to 15%. Thus, fabricated composite demonstrated synergistic aspects of energy. � 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
Synergistically modified WS2@PANI binary nanocomposite-based all-solid-state symmetric supercapacitor with high energy density
(Royal Society of Chemistry, 2022-03-09T00:00:00) Iqbal, Muzahir; Saykar, Nilesh G.; Alegaonkar, Prashant S.; Mahapatra, Santosh K.
The rapid development of intelligent, wearable, compact electronic equipment has triggered the need for durable, flexible, and lightweight portable energy storage devices. Nanomaterials that are capable of delivering the high specific power density and commensurate energy density are potential candidate for realizing such devices. Herein, we report the facile synthesis of a binary nanocomposite WS2@PANI by utilizing hydrothermal and physical blending techniques to assess it as an electrode material for high-performance supercapacitors. The nanocomposite electrode delivered specific capacitance >335 F g?1 @ 10 mV s?1 (two-electrode), achieving energy and power densities of ?80 W h kg?1 and ?800 W kg?1, respectively, with capacitance retention of 83% even after 5000 charge-discharge cycles @ 10 A g?1, all of which are superior to the WS2 electrode. Dunns model quantifies capacitive and intercalative contributions that showed the cumulative effect of both to realize a robust, cost-effective, and energy-efficient device. The strategically incorporated PANI broadened the electrochemical window and the device's overall performance, resulting in high specific energy density. We demonstrated that our all-solid-state symmetric supercapacitor could be used to illuminate a light-emitting diode and drive a rotary motor. We believe that our WS2@PANI binary nanocomposite will be a potential candidate for energy storage devices. � 2022 The Royal Society of Chemistry
Tellurium nanostructures for optoelectronic applications
(Springer Science and Business Media Deutschland GmbH, 2022-03-29T00:00:00) Rani, Pinki; Alegaonkar, Ashwini P.; Mahapatra, Santosh K.; Alegaonkar, Prashant S.
We report on fabrication of tellurium nanostructures (TN) that demonstrated promising applications in optoelectronics. Initially, TN were synthesized using a simple, one-step, room temperature, wet-chemical technique. During synthesis, the effect of number of parameters such as precursor concentration, its content, solvent ratios, their pH and reaction time has been investigated at a temperature ~ 120��C. The obtained product was examined by UV�visible, IR spectroscopy, X-ray diffractometry, electron microscopy and energy-dispersive X-ray spectroscopic characterization techniques. Analysis revealed that TN have profound impact on the structure�property relationship through active and passive participation of Mo catalyst. During its initial growth stages, Te and O bonding gets influenced by Mo to form Mo�O�Te�O and Te�Mo�Te moieties, typically, at 6�h. This has implication onto the structural phase transformation of TN from Te-tube (TT) to Te-flake (TF) and then to TT again. Possible transformation mechanism is explained. Structurally, TN had hexagonal quasi-crystalline atomic arrangement with morphologically thin, transparent, bunched and close-caped TT characteristics having diameter 50�100�nm and length 0.8�2.1��m, whereas TF is found to be thin, geometrically squared with area ~ 7 to 10 �m2. On their implementation for optoelectronic assessments, over the wavelength range 0.3�2.1��m (power density ~ 100 mW/cm2), they showed peculiar luminescent and dark I�V responses. Relevant photocarrier dynamics has been revealed. TT, typically, showed 160% quantum efficiency, whereas TF ~ 40% is useful for optoelectronic devices. Details are presented. Graphical abstract: Fabrication and optoelectronic assessments of tellurium nanostructure that showed time-dependent structural phase transformation from tube to flake to tube. [Figure not available: see fulltext.] � 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.