Journal Articles

Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/19884

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Author: search.filters.author.Muhiuddin, M.Subject: search.filters.subject.Nanocrystals

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    Facile and rapid method to synthesis sulfur and nitrogen co-doped graphene quantum dots as an electrode material with excellent specific capacitance for supercapacitors application
    (Elsevier Ltd, 2024) Muhiuddin, M.; Devi, N.A.; Bharadishettar, N.; Meti, S.; Siddique, A.B.; Satyanarayan, M.N.; Udaya, B.K.; Akhtar, W.; Rahman, M.R.
    The current invention pertains to the expeditious simple synthesis of electrode materials that improve the storage capacity of supercapacitors (SCs). Sulfur and nitrogen co-doped graphene quantum dots (SN-GQDs) are synthesized using a microwave-assisted hydrothermal (MAH) process at low pressure and with a short reaction time. The utilization of SN-GQDs in conjunction with Polyaniline (PANI) has the potential to enhance the supercapacitor's energy and power density, owing to their notable specific capacitance. Implementing SN-GQDs material as an SCs electrode, exhibiting an outstanding specific capacitance of 1040 F/g at an applied current density of 0.5 A g−1. Furthermore, a composite of SN-GQDs/PANI is synthesized and the electrochemical performance is compared with the as-synthesized PANI. The symmetrical SCs are fabricated using SN-GQDs/PANI composite, and PANI. At a current density of 0.5 A g−1 SN-GQDs/PANI composite-based SC displays a superior energy density of 44.25 Wh/kg at a power density of 1.227 kW/kg. This is high in comparison to PANI-based SC which shows an energy density of 18.71 Wh/kg at 0.8 kW/kg power density at the same current density. The SC created using SN-GQDs/PANI composite exhibits superior properties and is a promising material for SC applications. © 2024 Elsevier B.V.
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    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.
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    Efficiency enhancement in dye-sensitized solar cells through neodymium-doped graphene quantum dot-modified TiO? photoanodes
    (Elsevier B.V., 2025) Senadeera, G.K.R.; Weerasekara, W.M.S.K.; Jaseetharan, T.; Sandunika, P.U.; Kumari, J.M.K.W.; Dissanayake, M.A.K.L.; Muhiuddin, M.; Rahman, M.R.; Bhat K, U.; Akhtar, M.W.; Udayakumar, U.; Siddique, A.B.; Ekanayake, P.
    This study explored the effects of Neodymium-doped graphene quantum dots (NdGQDs) on improving the performance efficiency of TiO2 based dye-sensitized solar cells (DSSCs). By employing in-situ physical assisted mixing, DSSCs with optimized NdGQDs in TiO2 photoanodes showed a power conversion efficiency of 8.76 %, a significant improvement compared to the 6.01 % efficiency of pristine TiO2-based DSSCs under 100 mW cm?2 illumination (AM 1.5). Notably, the short-circuit current density increased by 74 %. HRTEM analysis revealed that the NdGQDs have a size range of approximately 7–9 nm. UV–visible spectroscopy and Mott-Schottky analysis revealed a positive shift in the Fermi level, promoting better electron transfer and increased photocurrent density at the expenses of the open circuit voltage. Electrochemical impedance spectroscopy characterization of DSSCs incorporating NdGQD-modified photoanodes revealed a reduction in electron transfer resistance at the photoanode|dye|electrolyte interface, accompanied by an increase in recombination resistance within the device suppressing the electron recombination rate. © 2024 Elsevier B.V.