Browsing by Author "Chauhan, S.S."

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Fabrication of Î²-Phase PVDF/MWCNTs Nanofibers on a Flexible Substrate for Energy Harvesting Application
(Institute of Electrical and Electronics Engineers Inc., 2024) Chauhan, S.S.; Sharma, S.; Muhiuddin, M.; Rahman, M.R.
It is challenging to deposit the pristine polyvinylidene difluoride (PVDF) in Î² crystalline phase on a flexible substrate since pristine PVDF exists in the Î±-phase. This paper presents a novel formation of nanofibers membrane of PVDF in which multiwall carbon nanotubes (MWCNT) is added as the composite in PVDF for transformation from Î± to Î² phase. The PVDF/MWCNTs nanofibers is electro spun after adding carboxyl functionalized MWCNT with PVDF to form the Î² phase. The field emission scanning electron microscope (FE-SEM) is used to characterize the presence of the nanofiber's membrane. X-ray diffraction (XRD) is used to characterize the Î² phase and Fourier-transform infrared spectroscopy (FTIR) is used to detect the functionalized bonds in the formation of PVDF/MWCNTs nanofibers on a flexible Polyethylene Terephthalate (PET). The measurement of the polarization of electric field hysteresis shows good characteristics with Ps, Pr, and EC are 9.58 Î¼C/m2, 4 Î¼C/m2, and 1 MV/m, respectively. The optimized film has a high potential for application as the piezoelectric material in energy harvesting devices fabricated on a flexible PET film. Â© 2024 IEEE.
Flexible and cost effective CNT coated cotton fabric for CO gas sensing application
(Elsevier B.V., 2023) D.s, A.K.; Chauhan, S.S.; Krishnamoorthy, K.; P, D.B.; Bharathi, K.D.; Ravikumar, A.; Rahman, M.R.
In this paper, a low-cost and room temperature flexible carbon monoxide (CO) gas sensor is presented using multi-walled carbon nanotubes coated cotton fabric. A dip and drying method is used to fabricate a lightweight, and high-performance fabric based CO gas sensor using different concentrations of multi-walled carbon nanotubes (MWCNTs). Transmission electron microscopy (TEM) is utilized for examining the deagglomeration of MWCNTs in the presence of a sufficient amount of surfactant. The field-emission scanning electron microscopy (FESEM) is used to evaluate the formation of a uniform network of MWCNTs on the cotton fabric. Fourier transform infrared (FTIR) spectroscopy is used to confirm the presence of functional groups which plays an important role in CO gas sensing. The fabricated cotton fabric coated with MWCNTs (CCM) sensors are tested with different concentrations of CO gas ranging from 25 ppm to 100 ppm at room temperature. It is found that in comparison to all other sensors, the CCM sensor coated with the higher concentration of MWCNTs (0.5 mg/ml) shows a maximum response of 9.11 % at 25 ppm and 15.2 % at 100 ppm concentration of CO gas respectively. The CCM 4 sensor shows the fastest response and recovery within 49s for 25–100 ppm of CO gas. Moreover, the fabricated CCM sensor exhibited good repeatability, reproducibility, and selectivity. These sensors are suitable for low-cost smart textile applications. © 2023 Elsevier B.V.
High energy density supercapacitor based on Ag doped MoO3 nanorods on a flexible carbon cloth
(Elsevier B.V., 2025) Sharma, S.; Chauhan, S.S.; Chappanda, K.N.; Rahman, M.R.
In this study, the plain MoO3 and Ag-doped MoO3 nanorods are anchored on a flexible fibrous carbon cloth using a hydrothermal method, and their performances are thoroughly evaluated by fabricating the supercapacitors using both types of nanorods. The doped substrate shows drastic enhancement in specific capacitance which is nearly four times greater than undoped MoO3 nanorods at a current density of 0.5 mA/cm2. Additionally, the Ag doped MoO3 shows an excellent energy density of 43 µWh/cm2. The superior performance of the doped nanorods is attributed to its pseudocapacitive behaviour, higher conductivity, and improved charge kinetics at the electrode–electrolyte interface, enabling a more efficient and potential supercapacitor-based energy storage system to drive future low power flexible and wearable electronic devices. © 2024 Elsevier B.V.
Highly Sensitive and Stable NO2 Gas Sensors Based on SWNTs with Exceptional Recovery Time
(2019) Chauhan, S.S.; Kumar, D.; Chaturvedi, P.; Rahman, M.R.
Room temperature operable and highly sensitive NO2 gas sensors are fabricated based on (i) random and (ii) aligned networks of single-walled carbon nanotubes (SWNTs). The fabricated sensors are very sensitive, stable, and show shorter recovery time in the presence of UV light. Also, the variation of the response and recovery with network density is analyzed. The thin film resistor (TFR) of random network is fabricated by a reliable, cost-effective, and reproducible vacuum filtration method. The aligned network is fabricated using AC di-electrophoresis (DEP) technique. Electrodes spacing is optimized to avoid the chaining effect of aligned and bridged SWNTs between the gold electrode pair to enhance the stability and sensitivity of the sensor. Both the sensors based on random and aligned networks of SWNTs is tested with NO2 at room temperature. It is found that the sensor made of the aligned network shows 3.5 times more sensitivity as compared to the random networks gas sensor but recovery time increases. It is also observed that sensors fabricated by TFR and aligned network techniques are stable and having less than 0.02 % and 0.15 % change in resistance with baseline, respectively. The TFR gas sensors fabricated using as prepared (AP) and purified and low functionality (P2) SWNTs show higher stability but less sensitive compared to the aligned network. The measured complete recovery time of sensors based on random and aligned SWNTs are 50 sec and 124 sec, respectively, for 0.5 ppm NO2. It is also observed that as the network density decreases response improves but the recovery time increases. 2001-2012 IEEE.
Highly Sensitive and Stable NO2 Gas Sensors Based on SWNTs with Exceptional Recovery Time
(Institute of Electrical and Electronics Engineers Inc., 2019) Chauhan, S.S.; Kumar, D.; Chaturvedi, P.; Rahman, M.R.
Room temperature operable and highly sensitive NO2 gas sensors are fabricated based on (i) random and (ii) aligned networks of single-walled carbon nanotubes (SWNTs). The fabricated sensors are very sensitive, stable, and show shorter recovery time in the presence of UV light. Also, the variation of the response and recovery with network density is analyzed. The thin film resistor (TFR) of random network is fabricated by a reliable, cost-effective, and reproducible vacuum filtration method. The aligned network is fabricated using AC di-electrophoresis (DEP) technique. Electrodes spacing is optimized to avoid the chaining effect of aligned and bridged SWNTs between the gold electrode pair to enhance the stability and sensitivity of the sensor. Both the sensors based on random and aligned networks of SWNTs is tested with NO2 at room temperature. It is found that the sensor made of the aligned network shows 3.5 times more sensitivity as compared to the random networks gas sensor but recovery time increases. It is also observed that sensors fabricated by TFR and aligned network techniques are stable and having less than 0.02 % and 0.15 % change in resistance with baseline, respectively. The TFR gas sensors fabricated using as prepared (AP) and purified and low functionality (P2) SWNTs show higher stability but less sensitive compared to the aligned network. The measured complete recovery time of sensors based on random and aligned SWNTs are 50 sec and 124 sec, respectively, for 0.5 ppm NO2. It is also observed that as the network density decreases response improves but the recovery time increases. © 2001-2012 IEEE.
Neodymium doped graphene quantum dots/PANI composite for supercapacitor application
(Elsevier Ltd, 2025) Muhiuddin, M.; Bharadishettar, N.; Devi, N.A.; Gautam, A.; Chauhan, S.S.; Siddique, A.B.; Ahmad, M.I.; Satyanarayan, M.N.; K, U.B.; Akhtar, W.; Rahman, M.R.
The publication presents a streamlined and economical technique for fabricating advanced electrode materials to enhance the energy storage capabilities of supercapacitors (SCs). The focus is on synthesizing neodymium-doped graphene quantum dots (Nd-GQDs) via a microwave-assisted hydrothermal (MAH) process. This method uses microwave irradiation's rapid heating and efficient energy transfer under low pressure and minimal reaction time. The resulting Nd-GQDs exhibit enhanced electrochemical properties, including increased capacitance and improved charge storage, making this approach practical and effective for advancing supercapacitor technology. An exceptional specific capacitance of 618 F g?1 at a 5 mV s?1 scan rate is demonstrated using Nd-GQDs as the SC electrode material. Due to their high specific capacitance, Nd-GQDs, when combined with polyaniline (PANI), improve the energy and power density of SCs. Nd-GQDs/PANI composites with varying amounts of Nd-GQDs in symmetric SCs are fabricated to demonstrate their promising properties for SC applications. SCs fabricated with 20 mL of Nd-GQDs in the PANI matrix showed a superior specific capacitance of 354 F g?1 at a current density of 1 A g?1, while the energy density and power density were 49.15 Wh kg?1 and 2000 W kg?1, respectively. © 2025 Elsevier B.V.