Journal of Advances in Engineering and Technology [JAET]
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The Journal of Advances in Engineering and Technology (JAET) is an international, open access, double blind peer-reviewed journal. It is published by the Faculty of Engineering of Sri Lanka Institute of Information Technology (SLIIT). The JAET aims at fostering research and development work in Engineering and Technology and bringing researchers on to a common platform. Furthermore, JAET will also accept review articles on appropriate subject areas including concept papers of academic opinions, book reviews, etc. for publication therein.
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Item Open Access Synergistic Charge Dynamics and Light Harvesting in TiO₂/MgO Composites for Efficiency Enhancement in CdS Quantum Dot-Sensitized Solar Cells(Faculty of Engineering, 2026-01) Ajward, N.F.; Fernando,J.V.P.; Perera, V.P.S.Quantum dot-sensitized solar cells (QDSSCs) represent a promising advancement in renewable energy technologies, with recent improvements achieving power conversion efficiencies close to 6%. Structurally similar to dye-sensitized solar cells (DSSCs), QDSSCs employ quantum dots (QDs) as sensitizers that absorb photons and inject excited electrons into the conduction band of a wide-bandgap semiconductor electrode, while the redox electrolyte removes the generated holes and completes the circuit through regeneration at the counter electrode. Quantum dots composed of materials such as CdS, CdSe, PbS, and InP are increasingly studied for use in QDSSCs, offering the advantage of tunable optical band gaps through particle size manipulation. This adaptability enhances QDSSCs’ design potential, enabling the integration of third-generation solar cell configurations, including multiple exciton generation (MEG), to further improve energy conversion efficiency. Despite these advancements, QDSSC performance is currently limited by issues such as reduced photovoltage and recombination losses at the TiO₂-QD-electrolyte interface. This study investigates the effect of MgO incorporation into TiO₂ photoanodes on the photovoltaic performance of CdS QDSSCs, with particular attention to the fill factor (FF) and overall cell efficiency. MgO is expected to act as an interfacial passivation layer suppressing combination and improving charge-selective transport. In addition, MgO may enhance light scattering within the photoanode, thereby improving light harvesting and short-circuit current density. In this study, MgO powder was incorporated in specific mass ratios with TiO₂, followed by the application of CdS quantum dots (QDs) on the TiO₂/MgO composite layer using the SILAR method. Results indicated a significant improvement in the fill factor (FF) at an optimal MgO-to-TiO₂ ratio, attributed to synergistic effects of MgO on interface stabilization, reduced recombination, and enhanced charge transport. The optimized MgO-modified TiO₂ films achieved a current density of 1.95 mA cm-2, voltage of 437 mV, and power of 0.121 mW (active area = 0.49 cm²), reaching an efficiency of 0.311 % (18.7% higher than TiO₂/CdS QDSCs), with improved interfacial impedance, Incident Photon to Current Efficiency (IPCE), and FF of 0.374.Publication Open Access Use of Ascorbic Acid Linker in Enhancing the Photovoltaic Performance of CdS/TiO2 Quantum Dot Sensitized Solar Cells(SLIIT, Faculty of Engineering, 2025-01) Ajward, N.F.; Davisan, S.; Perera, V.P.S.This study explores the use of ascorbic acid to enhance the photovoltaic performance of CdS/TiO2 Quantum Dot Sensitized Solar Cells (QDSSCs). Ascorbic acid acts as a mild reducing agent, donating electrons to Ti atoms on the TiO2 film, effectively filling oxygen vacancies known to act as recombination centers for photogenerated charge carriers. By passivating these detrimental sites, ascorbic acid facilitates improved carrier transport and reduces recombination, ultimately boosting photocurrent and overall efficiency. QDSSCs fabricated via the Successive Ionic Layer Adsorption and Reaction (SILAR) method were characterized using I-V measurements, Incident Photon to Current Conversion Efficiency (IPCE), Impedance Spectroscopy (IS), and overall power conversion efficiency. The optimized cell incorporated with ascorbic acid demonstrated a remarkable improvement compared to the control, achieving a short circuit current density (Jsc) of 4.863 mA/cm², open circuit voltage (Voc) of 446.1mV, efficiency of 1.368%, fill factor of 24.6%, and maximum power of 0.342mW. Optimization of ascorbic acid absorption time and precursor concentrations resulted an impressive 68.26% enhancement in efficiency (from 0.813% to 1.368%) and increase in maximum power from 0.163 mW to 0.342 mW for 0.64 cm². cell. This study highlights the potential of ascorbic acid as a simple and effective strategy for enhancing the performance of CdS/TiO2 QDSSCs, paving the way for further developments in low-cost and efficient solar cell technologies.Publication Open Access Fabrication, Characterization, and Gas Sensing Properties of Different Semiconductor Metal Oxide Nanostructures for LPG Detection: A Comparative Study(SLIIT, Faculty of Engineering, 2025-01) Bandara, A.H.M.N.N.; Senadeera, G.K.R.; Bandara, K.N.D.; Perera, V.P.S.The research explores how the structural, morphological, and electrical properties of nanostructured semiconductor metal oxides (SMOs), including Cu2O, ZnO, TiO2, and reduced graphene oxide (rGO), synthesized via electrochemical deposition and doctor blading techniques, influence their effectiveness in sensing liquid petroleum gas (LPG). Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis were used to assess the chemical composition and structure. Cu2O, ZnO, and TiO2 were found to exhibit significant polycrystalline structures, with increasing average crystallite sizes of approximately 42.8 nm, 70.1 nm, and 87.78 nm, respectively. The dominant (111) Cu2O phase displayed a homogeneous cuboid morphology. rGO exhibited a singleplane (002) microstructure with a crumpled paper texture and an average crystallite size of ~85.3 nm, indicating a successful hydrothermal reduction of graphene oxide (GO). UV-vis absorption spectra in the range of 200 – 800 nm revealed the presence of different energy bands in ZnO, TiO2, and rGO, alongside their major band energies of 3.2 eV, 3.3 eV, and 1.9 eV. Cu2O thin films, with the lowest band energy gap of 2.5 eV, exhibited high photocatalytic activity, potentially enhancing chemical reaction rates during gas sensing under light exposure. Additionally, alternating current (AC) impedance spectra of SMO indicated increased film conductivities with positive bias voltages. ZnO films showed the most significant gas response (~27%) for LPG sensing at 70 ℃, with response and recovery times of less than 20 seconds. A stable and considerably high LPG sensitivity of ~11% was discovered with Cu2O. This finding underscores the significance of its relatively small grain size in influencing its sensitivity to LPG.