Faculty Publications
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Item Assessment of triboelectricity in colossal-surface-area-lanthanum oxide nanocrystals synthesized via low-temperature hydrothermal process(Springer, 2021) Meti, S.; Hosangadi Prutvi, H.P.; Rahman, M.R.; Bhat, K.U.Triboelectric nanogenerators (TENGs) have marked their applications in various fields, most importantly, in medical devices. The electrical output of the TENGs mainly concentrated on parameters such as electrode separation distance, applied mechanical pressure, surface charge density, and overlapping surface area. The surface area of the active layer in TENGs plays a crucial role. Given this, the present contribution is the first report on the utilization of lanthanum oxide (La2O3) as an active material with a large surface area (~ 72.33 m2/g) in TENGs. The nanocrystals of La2O3 have been successfully embedded into TENGs architecture through a high-quality screen-printed film with a Teflon-counter surface. The in-house test-rig of TENGs resulted in an output open-circuit voltage of 120 V and a short-circuit current of 23.7 ?A. Further, the maximum power density is 7.125 W/m2 at an external load resistance of 30 M?. These results suggest that La2O3 is a suitable contender in various self-powered devices. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.Item 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.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 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.