dr. S Kundu

1. Fabrication of high-performance visible-blind ultraviolet photodetectors using electro-ionic conducting supramolecular nanofibers
   S. Kundu; S. J. George; G. U. Kulkarni;
   ACS Appl. Mater. Interfaces,
   Issue 15, pp. 19270, 2023. DOI: https://doi.org/10.1021/acsami.3c00716

2. Emulating Ebbinghaus forgetting behavior in a neuromorphic device based on 1D supramolecular nanofibres
   T.S. Rao; S. Kundu; B. Bannur; S. J. George; G. U. Kulkarni;
   Nanoscale,
   Issue 15(16), pp. 7450-7459, 2023. DOI: https://doi.org/10.1039/D3NR00195D

3. Fabrication of High-performance Supercapacitors Using Hierarchical MnO2 Nanostructures on a Frosted Glass Surface.
   S. Kundu; G. U. Kulkarni;
   Energy Technology,
   July 2022. DOI: 2200505
   
   Abstract: ...

   Supercapacitors have emerged to fill the gap between batteries and capacitors. The electrodes comprising a high surface area are utilized to fabricate the supercapacitors. However, the processes involved to fabricate electrodes are often strenuous and time-consuming. Herein, the fabrication of high-performance supercapacitors using frosted glass as a template to grow electrodes is reported. The frosted substrates can host much higher ions owing to the numerous surface features arising from micro- and nano-level roughnesses, resulting in one order higher capacitance than the plain surface. Electrodepositing MnO2 nanostructures on the frosted surface further increases the capacitance and attains the highest value of 11 mF cm−2 at 300 min of electrodeposition, which is 6.5 times higher than the electrodes without MnO2. The stacked supercapacitors are made using polyvinyl alcohol/H2SO4 gel electrolyte, and the devices exhibit superior electrochemical properties such as high scan rate stability (100 V s−1), high cut-off frequency (333 Hz), low iR drop, high cyclic stability (93% capacitance retention after 10 000 cycles), and low self-discharge. The roughened nature of the frosted glass can be imprinted onto the surface of polydimethylsiloxane substrate to fabricate flexible and stretchable supercapacitors. The present work can pave the way for facile and low-cost fabrication of supercapacitor electrodes.
   
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4. Parts per billion sensitive, highly selective ambient operable, ammonia sensor with supramolecular nanofibres as active element.
   S. Kundu; S. J. George; G. U. Kulkarni;
   Sensors and Actuators B: Chemical,
   Volume 347, November 2021. DOI: 130634
   
   Abstract: ...

   Ammonia is among the most produced chemicals worldwide, and the detection in case of leakage is crucial because of its adverse effects on human health and the environment. The efficacy of commercial metal oxide-based ammonia sensors is limited because of their poor selectivity and high power requirements. In this article, we report the fabrication of a high performance ammonia sensor using 1D supramolecular nanofibres as the active material. The fibres are an inverse micellar assembly of a donor, coronene tetracarboxylate (CS) and an acceptor, dodecyl methyl viologen (DMV), with an absorbed water layer around which dissolves and ionises ammonia molecules and improves conductivity. The sensor can effectively detect ammonia at moderate humidity values (> 60% RH) without using an additional heating element. The sensors can even detect 1 ppb of ammonia with a remarkable response of around 40%. The response and recovery times are of few seconds, better than most of the literature reports. The present sensor shows high selectivity and response towards ammonia compared to the commercial ammonia sensors tested in this work. The sensor fabricated on PET substrate demonstrated good stability with almost 90% retention of the initial response even after 2000 bending cycles. In combination with a commercial humidity sensor, the present ammonia sensor could differentiate between humidity and ammonia. The real-time detection of ammonia is shown possible by integrating the present device on an Arduino micro-controller board.
   
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5. Aesthetically acceptable, breath friendly triboelectric face masks: design, fabrication and its efficacy
   P. K. Santra; A. K. Singh; G. U. Kulkarni; S. Kundu; T. S. Rao; M. K. Ganesha;
   Energy Technology,
   September 2021.
   
   Abstract: ...

   Since the beginning of the COVID-19 pandemic, several attempts have been made worldwide to control the spread of the virus. It is widely accepted that wearing face masks in public and workplaces suppresses the transmission of the virus. Highly effective face masks, e.g. N95, have a high filtration efficiency but with a large pressure drop, which does not allow one to wear the mask comfortably for long hours. A larger population wearing a moderate efficiency mask can also cut the transmission at large. Herein, mask panels from readily available fabrics are developed, that can generate triboelectricity, which enhances the filtration efficiency by around 18% without compromising the pressure drop—allowing one to wear the mask for an extended period. The unique cup-shaped design of the mask provides a snug fit with no speech distortion or fogging on the glasses.
   
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6. Extended X-Ray Emission Associated with the Radio Lobes and the Environments of 60 Radio Galaxies.
   A. Gill; M. M. Boyce; C. P. O'Dea; S. A. Baum; P. Kharb; N. Campbell; G. R. Tremblay; S. Kundu;
   The Astrophysical Journal,
   May 2021. DOI: 912 88
   
   Abstract: ...

   The Astrophysical Journal The American Astronomical Society, find out more The Institute of Physics, find out more Extended X-Ray Emission Associated with the Radio Lobes and the Environments of 60 Radio Galaxies Ajay Gill1,2, Michelle M. Boyce3, Christopher P. O'Dea3, Stefi A. Baum4, Preeti Kharb5, Neil Campbell6, Grant R. Tremblay7, and Suman Kundu8 Published 2021 May 7 • © 2021. The American Astronomical Society. All rights reserved. The Astrophysical Journal, Volume 912, Number 2 Citation Ajay Gill et al 2021 ApJ 912 88 DOI 10.3847/1538-4357/abec74 DownloadArticle PDF DownloadArticle ePub Figures Tables References 840 Total downloads 22 total citations on Dimensions. Turn on MathJax Get permission to re-use this article Share this article Share this content via email Share on Facebook (opens new window) Share on Twitter (opens new window) Share on Mendeley (opens new window) Article and author information Abstract This paper studied the faint, diffuse extended X-ray emission associated with the radio lobes and the hot gas in the intracluster medium (ICM) environment for a sample of radio galaxies. We used shallow (∼10 ks) archival Chandra observations for 60 radio galaxies (7 FR I and 53 FR II) with 0.0222 ≤ z ≤ 1.785 selected from the 298 extragalactic radio sources identified in the 3CR catalog. We used Bayesian statistics to look for any asymmetry in the extended X-ray emission between regions that contain the radio lobes and regions that contain the hot gas in the ICM. In the Chandra broad band (0.5–7.0 keV), which has the highest detected X-ray flux and the highest signal-to-noise ratio, we found that the nonthermal X-ray emission from the radio lobes dominates the thermal X-ray emission from the environment for ∼77% of the sources in our sample. We also found that the relative amount of on-jet axis nonthermal emission from the radio lobes tends to increase with redshift compared to the off-jet axis thermal emission from the environment. This suggests that the dominant X-ray mechanism for the nonthermal X-ray emission in the radio lobes is due to the inverse Compton upscattering of cosmic microwave background (CMB) seed photons by relativistic electrons in the radio lobes, a process for which the observed flux is roughly redshift independent due to the increasing CMB energy density with increasing redshift.
   
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7. Electric field assisted assembly of 1D supramolecular nanofibres for enhanced supercapacitive performance
   S. Kundu; S. J. George; G. U. Kulkarni,;
   Journal of Materials Chemistry A,
   Volume 8, pp. 13106 - 13113, 2020. DOI: DOI https://doi.org/10.1039/D0TA03901B
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8. Humidity sensing and breath analyzing applications of TiO2 slanted nanorod arrays.
   H. Jyothilal; G. Shukla; S. Walia; S. Kundu; and S. Angappane;
   Sensors and Actuators A: Physical,
   Volume 301, January 2020. DOI: 111758
   
   Abstract: ...

   Humidity sensing devices are fabricated using titanium dioxide nanorod arrays and studied in this work. TiO2 slanted nanorods were grown by using electron beam assisted physical evaporation technique by keeping quartz substrates at a glancing angle of 80°. TiO2 slanted nanorod arrays were characterized using XRD, FESEM with EDS, HR-TEM, and Raman spectroscopy techniques. XRD characterization reveals that as-deposited nanorods are amorphous, and annealing at 500 ℃ for 6 hrs leads to anatase crystal structure. FESEM confirms the growth of uniformly distributed nanorods without any cracks throughout the substrate. Further, the humidity sensing property was analyzed for both as-deposited and annealed samples with bottom gap electrode configuration. The sensing towards a wide humidity range was tested for fabricated TiO2 devices of both as-deposited and annealed TiO2 nanorods in a homemade humidity sensing setup. Remarkably, the annealed TiO2 nanorod sensor is found to be having high sensitivity and fast response and recovery times of 145 and 210 ms, respectively, for 95 % humidity. Finally, to check the practical applicability, the TiO2 nanorod sensors were used to analyze the humidity level in exhaled human breath to determine the dehydration level.
   
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9. A planar supercapacitor made of supramolecular nanofibre based solid electrolyte exhibiting 8 V window
   S. Kundu; U. Mogera; S. J. George; G. U. Kulkarni;
   Nano Energy,
   Volume 61, pp. 259-266, 2019.
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