Faculty Publications
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Item 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.Item The cohesion strength of electrodeposited Zn/GO nanocomposite coating on stainless steel(Elsevier Ltd, 2025) Bharathi, K.D.; Udaya Bhat, K.; Bhat Panemangalore, P.; Arun Kumar, D.S.; Rahman, M.R.Graphene based nanocomposite coatings have incredible scope in enhancing the physical properties of composite materials. In this study, pure Zn and Zn/GO nanocomposite coatings were successfully prepared by electrodeposition technique on the SS304 stainless steel. The Zn/GO nanocomposite coatings were prepared by varying concentration of GO, coating time and CTAB ratio. The nanocomposite coatings were characterized by using the Field emission scanning electron microscopy (FESEM), X-ray diffractometry (XRD), Energy-dispersive X-ray spectroscopy (EDS), and Raman spectroscopy. Cohesion strength (LC) using scratch test at RT noticed that the LC values increased with the concentration of GO. The scratch tests revealed that Zn/GO composite produced using 40 mgL?1 GO had 70 % increase in cohesion strength (LC1) in comparison to pure Zn coating deposited with 30 min of coating time at a ratio of 1:2 GO:CTAB. The magnitude of the residual stress in the nanocomposite coating decreases from ?32 MPa (0 mgL?1 of GO) to ?11 MPa (40 mgL?1 of GO) as the GO concentration increases in coatings due to the effect of the kinetic movement of particles while deposition. © 2024Item 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.