Department of Physics
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Item Investigation of Doped (III-V) Group Elements Emissive Layer for Visible LED Applications(2019) Aqsa Hashmi; CIIT/FA17-RPH-043/LHR; Dr. Farah Alvi; LHR TP 5728This study Sb2S3 was prepared by applying hydrothermal technique with different concentration of Ag as a doping impurity to improve its optical and electrical properties to be used in optoelectronics for LED applications. FTIR spectra was used to analyze the vibrations of chemical bonds present in the different groups in the sample. The intensity of the peaks is reduced with the increase in doping concentration, this is because the strength of chemical bonds decreases because of intermolecular transition of groups present in the sample. Optical properties were studied by UV-Vis and PL spectroscopy. UV-vis spectra was used to calculate bandgap that comes out between 2.5-1.9 eV. The bandgap was reduced with the increase in doping concentration of Ag which indicate its good compatibility for LED applications. IV measurements were used to analyze IV characteristics of the samples and to find out the turn on voltage of the device. SEM results were helpful in analyzing the surface morphology of the samples and measuring the particle size. The device was characterized by electroluminescence spectra which confirmed the red emission from LEDs having emissive layers of undoped and doped Sb2S3. So the materials have bright future for visibe LED applications.Item Development of Efficient Electrolyte for Semiconductor Ionic Membrane Fuel Cell(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2024) Muhammad Danish; CIIT/SP23-RPH-006/LHR; Prof. Dr. M Ashfaq Ahmad; LHR TP 9627In this study, electrolyte was fabricated for semiconductor ionic membrane fuel cells. Barium and Bismuth doping with ceria electrolyte for semiconductor ionic membrane fuel cell was prepared successfully. All of these samples were prepared by co- precipitation method. These synthesized electrolyte materials give better results and beneficial for more oxygen ions vacancies which oxidation reduction reaction enhanced. The synthesized material characterized by using FTIR Spectroscopy, Raman Spectroscopy, UV-Vis spectroscopy, X-ray diffraction and Electrochemical Impedance Spectroscopy. Raman spectra show vibration modes and the structure of materials particles. Raman analysis of samples was done from 700- 900 °C. These results showed the strong peak of cerium oxide in range of 450 to 470nm and the weak intense peak representing oxygen ion vacancies. It indicates the kind of shifting that is taking place in the prepared material. Blue shifting and a decreasing wavelength are seen in all produced materials, indicating a decrease in particle size. In UV-Vis spectroscopy result demonstrated the band gap values which ranges from 3.28 eV for BaCeO2, 3.39 eV for BiCeO2, and 3.3 eV for co doped BaBiCeO2. With the help of XRD compositions and structure was confirmed, which is found to be cubic. EIS tells about the ionic and electronic behavior of materials. The maximum OCV of 888V for BaCeO, 550V for BiCeO and 732V for BaBiCeO at 550°C. The maximum current density of 309mA/cm2 for BaCeO, 202mA/cm2 for BiCeO and 123mA/cm2 for BaBiCeO at 550°C. The maximum power density of 93.3mW/cm2 for BaCeO, 33.27mW/cm2 for BiCeO and 31.6mW/cm2 for BaBiCeO at 550°C.Item Efficient Strategies to Enhance the Conductivity in Perovskite Materials for Intermediate Temperature Solid Oxide Fuel Cell (IT-SOFC)(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2021) MUBEEN YOUSAF; CIIT/FA19-RPH-055/LHR; Dr. Muhammad Ajmal Khan; LHR TP 7676Renewable energy sources are growing increasingly essential in this day. In order to avert climate change, they will play and expect a more important role in the near future. Fuel cells have gotten a lot of interest in this context because of their high conversion efficiency when compared to traditional energy conversion systems. Solid oxide fuel cells (SOFC) are one of the finest energy conversion technologies available, with minimal hazardous emissions, pollution, fuel adaptability, and expense materials properties. However, there are still some issues to be resolved; for example, the activity of SOFCs at low temperatures is reduced due to interfacial polarization blockages and also the oxygen reduction process (ORR). Lanthanum Iron Copper Oxide Cathode materials are created to increase activity and ORR. The cathode materials La1Fe1-xCuxO3–δ where x= 0.1, 0.3, 0.5 and 0.7 are synthesis by sol gel method. Their characteristics are investigated by various characterizations such as Raman Spectroscopy, Fourier Transformation Infrared Spectroscopy (FTIR), X-Rays Diffraction (XRD), and Electrochemical Impedance Spectroscopy (EIS). Prominent bands at peak positions 158, 290, 305, 960 cm −1 wavelengths are observed through Raman spectra of La1Fe1-xCuxO3–δ at x = 0.1, 0.3, 0.5 and 0.7 cathodes, analogous to lanthanum site vibration, typical stretching, symmetric stretching vibrations for Cu-O band, phonon mode, octahedral tilt vibrations, D band and associated with Ag and Bg double energy band. The prominent peaks at 675, 855, 1056, 1458, 1645 and 2830 cm -1 wavelengths observed through FTIR Analysis, these peaks attributed to stretching vibration of La-O bond, Cu-O stretching vibration, bending vibration of C-H in gaseous, asymmetric and symmetric O-C-O stretching vibrations, bending mode of H-O-H bond vibrations. XRD also provide crystal structure of materials. Two cards from La1Fe0.9Cu0.1O3–δ (JCPDS card number 96-100-8543) and (JCPDS card number 96-901-4244) have an orthorhombic structure. Two cards from La1Fe0.7Cu0.3O3–δ (ICSD card No 96-900-2333) and (ICSD card No 96-100-8573) shows an orthorhombic structure. Two cards from La1Fe0.5Cu5.5O3–δ (ICSD card No 96-901-5232) and (ICSD card No 96-200-2184) show an orthorhombic structure. Two cards from La1Fe0.3Cu0.7O3–δO3–δ (ICSD card No 96-100-8930) and xi (ICSD 96-200-1419) describe hexagonal and orthorhombic Structure. Electrochemical Impedance Spectroscopy is use to analyze the electronic and ionic behavior of the material. Material La1Fe0.3Cu0.7O3–δ has good electronic behavior and enhanced the maximum ORR of material.Item Direct Internal Reforming of Methane Fueled Solid Oxide Fuel Cell by Effective Catalyst(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2017) MUHAMMAD UMAIR; CIIT/SP16-RPH-001/LHR; Dr. Rizwan Raza; LHR TP 6994Fuel cell is a device that produces power through chemical reaction without combustion. It is more effective among other source of energy. It is an environment friendly low or zero emission, high productivity, multi-fuel capacity, versatility. In this project, the work is done on the catalytic study of Solid Oxide Fuel Cell (SOFC). In SOFC, the most commonly materials are used ceramic based materials e.g. for electrolyte Yttria-Stabilized Zirconia(YSZ) but it require high working temperatures (700– 1000 °C) and can be keeping running on different fuels including natural gas. In this project, the electrode (LiNiCuZnFeO) is prepared by Solid State Reaction (SSR) method. The compatible electrolyte (LNK-SDC) is prepared by co-precipitation method. Three catalyst of different molar ratio of Barium Nickel Cobalt [Sample no.1 (Ba0.2Ni0.4CO0.4O3), Sample no.2 (Ba0.2Ni0.6CO0.2O3), Sample no.3 (Ba0.2Ni0.2CO0.8O3)] are prepared for direct internal reforming of SOFC using sol-gel method. Natural gas is used as a fuel for SOFC. The best performance of the cell is achieved at 650℃ with Sample no.2 (Ba0.2Ni0.6CO0.2O3) with maximum open circuit voltage (OCV) of 0.7V, current density of 250 mAcm-2 and power density of 64mWcm-2 with highest conductivity of 0.42 S/cm.Item Synthesis of Catalyst for Direct Ethanol Fuel Cell and its Electrochemical Characterizations(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2018) NAZIM ALI EJAZ; CIIT/SP16-RPH-004/LHR; Dr. Rizwan Raza; LHR TP 6910Fuel cell is a device which uses to generate electric current by chemical reaction without any kind of combustion and noise. It is environmental friendly and more efficient among all the other energy devices. Now the increasing interest of direct alcohol fuel cell (DAFC) is emphasized as an alternate source of clean, cheap, reliable and minimal environmental impact energy. Mostly methanol is used as a fuel but due to its toxicity, alternatively ethanol is used as a fuel due to its some advantages like nontoxic and its availability from biomass resources. In this research, a suitable catalyst for direct ethanol fuel cell (DEFC) is synthesized, which increase the rate of oxidation of ethanol into CO2. The purpose of this work is to reduce the poisoning effect which will increase the activity of electrode. The operating temperature of direct ethanol solid oxide fuel cell (DESOFC) is within the range 600-1000°C. Three samples with different molar ratio are prepared Li0.1Ni0.5Cu0.1Ce0.3 oxides, Li0.1Ni0.5Cu0.2Ce0.2 oxides and Li0.1Ni0.5Cu0.3Ce0.1 oxides by sol-gel method. The best results are shown by Li0.1Ni0.5Cu0.1Ce0.3 oxides the highest conductivity is 0.27 S/cm at 750°C and power density 20 mWcm-2 at 700°C observed.Item Electrochemical study of Graphene/ Graphene Oxide/ Reduced Graphene Oxide in Fuel Cell(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2018) MUHAMMAD EHSAN; CIIT/FA15-RPH-034/LHR; Dr. Ghazanfar Abbas; LHR TP 6413Graphene is of major importance in a very wide range of applications. Different works are under progress to make the products better in durability, performance and in other properties using graphene. In this work, the major objective was focused to use the graphene/graphene oxide/reduced graphene oxide into Solid Oxide Fuel Cell (SOFC) to reduce its operating/working temperatures with better performance. As SOFC operates at high temperature that is one of the major problems, so by using graphene/graphene oxide/reduced graphene oxide the performance and durability of SOFC will be under consideration at a temperature of < 600 °C. It could provide good performance in asymmetrical solid oxide fuel cell because it can be a good potential to be an alternative cathode material for LT-SOFCs. For the confirmation of results different characterization tests are performed including XRD, SEM, DC conductivity and Fuel cell performance. In this work the newly developed SOFC materials are analysed to check the performance/efficiency and find the applications in new energy devices. In this project, I prepared 12 nanocomposite anode materials for LT-SOFC. All samples were successfully synthesized by simple and cost effective methods (Sol-gel method and Solid State). The XRD results show that the synthesized materials are in nano scale. The structure of the all samples was Perovskite. The average crystalline size of all prepared sample lies in the range of 22-300 nm. The sample LNCZ + 30% GO shows the maximum electrochemical performance as compared to other compositions of graphene Oxide and graphene. The electrochemical performance of LNCZ + 30% GO was measured with OCV of 0.155V, current density 450 mAcm-2, power density 105 mW/cm-2 at 4000C with the hydrogen fuel. It shows better results as compared to graphene because it has dual phase composite structure and since its oxide material so GO treat batter with LNCZ-Oxide rather the graphene. The nanocomposite structures help to enhance the conductivity and performance of the cell at low temperature. So this nanocomposite material which have perovskite structure can be considered as better anode materials for LTSOFCs.