Department of Physics

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    Investigation of Nickel Substituted Magnesium Ferrites (NixMg1-xFe2O4, x = 0.0, 0.33, 0.67, 1.0) Prepared by Hydrothermal Technique
    (Library Information Services, COMSATS University Islamabad, Lahore Campus, 2022) Zeenat Jabeen; CIIT/FA20-RPH-002/LHR; Dr. Mukhtar Ahmad; LHR TP 8348
    Nickel substituted magnesium ferrites (NixMg1-xFe2O4) were prepared by hydrothermal technique to examine the effect of nickel substitution on the structural, magnetic and electrochemical properties of these materials. The samples were characterized using X ray diffraction, Fourier Transmission Infrared spectroscopy (FTIR), Raman, Cyclic Voltammetry (CV), Scanning Electron Microscopy (SEM) and VSM techniques. XRD diffraction indicated a single-phase spinal structure, and the lattice parameter was lowered from 8.40 Å to 8.33 Å. It was found that the Raman mode for pure magnesium ferrite was 140cm-1, and this mode decreased in frequency as the Ni concentration increased because the ionic radius of Ni is smaller than that of magnesium. Using FTIR, observed that the absorption band at the octahedral site of pure magnesium ferrite is 601cm-1, and that this band changed toward smaller frequencies when Ni concentration increased due to the increasing bond length. Analyzing the electrochemical kinetics of the synthesized sample was made possible according to cyclic voltammetry. With an increase in scan rate, the specific capacitance decreases and the loop size grows, according to results from CV. Scanning Electron Microscopy (SEM) was used to measure the grain size and exterior surface morphology of the produced ferrites. The saturation magnetization and magnetic moment of magnesium ferrites increase as the Ni concentration increases according to M-H loop.
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    The Alkali (Li, Na) Based Solid State Ion Conductors Electrolytes for Solid State Batteries
    (Library Information Services, COMSATS University Islamabad, Lahore Campus, 2022) ALEEMA MASOOD; CIIT/FA20-RPH-022/LHR; Dr. Rizwan Raza; LHR TP 7983
    Initially, the energy storage devices based on liquid electrolytes are widely used to provide the continuous channel for energy transportation. Some drawbacks are (environmentally harmful and thermally unstable) that limits their commercial applications. While considering environmental aspects, the researchers move to find the environmental friendly, and thermally stable solid state electrolyte based energy storage devices. In this era, the solid state batteries become a center piece of research as the foremost candidate with great safety concern, high energy densities, cost effective and environmental friendly. In solid state batteries, the alkali based garnet type solid state electrolyte materials are thermally stable, eco-friendly, and have high energy density. In modern world, the consumption of lithium ion batteries surge day by day. There are limited raw resources for lithium, therefore researcher move to stir up to find alternative of lithium. Sodium can be considered as the best alternative of lithium. However, sodium is one of the most abundant element in the earth crust. In this research, alkali based garnet type solid state electrolyte as Li7La3Zr2O12 and Na2La3Zr2O12. The main objective of this work is to examine the ionic behavior, homogeneity, porosity, effect for the slid sate batteries. The x-rays diffraction is used to study the crystal structure of the material. The phase of the synthesized material is examined by high score expert. The prepared material is garnet type material with space group Fd-3m. The scanning electron microscopy is used to analyze the morphology of the synthesized electrolyte materials. The cyclic voltammetry and AC impedance spectroscopy are used to determine the charging and discharging rate, and ionic behavior of the materials. The ionic conductivity of both materials has comparable value for Li7La3Zr2O12 observed at room temperature 2.39×10 -6 Scm -1 . The optical band gap of both synthesized materials is analyzed by ultra violet visible spectroscopy. The Raman spectroscopy technique is used to determine the vibrational energy modes of both synthesized materials.
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    Fabrication of Breast Cancer Phantom for the Estimation of Radiation Dose in Breast Cancer Radiotherapy
    (Library Information Services, COMSATS University Islamabad, Lahore Campus, 2022) Sahar Khalid; CIIT/FA20-RPH-008/LHR; Dr. Naima Amin; LHR TP 7975
    A Gel-based breast tumor phantom was fabricated to estimate radiation dose in breast cancer radiotherapy. The materials used have similar properties to real tumor tissues. Vegetable oil was used as a source of fats and lipids in the Phantom, while Gelatinwas used as a source of protein to make equivalent breast tumor tissues. NaCl was added to increase the Phantom's conductivity. Different characterization techniques were used to analyze the equivalency of tumor phantom with real breast tumor tissues. The bonding characteristic in FTIR spectra shows different organic compositions in the Phantom. X- ray diffraction was used for structural properties to find crystalline structure in the Phantom. It shows the highest crystalline structure peak at [200] planes due to the presence of NaCl. The swelling test helped to swell the tumor phantom with the right water content equivalent to real tumor tissues. The swelling ratiowas increased until 35 minutes later, and the sample started to degrade. Degradation was used to check the life span of a phantom. 40 Gy of Radiation dose was given to the tumor phantom, which led to the breakage of ester bonds in the Phantom, similar to the breakage of phospholipids in the cell membrane of breast tumor cells after the radiation was given.
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    Extraction of Activated Carbon from Biomass for Energy Storage Applications
    (Library Information Services, COMSATS University Islamabad, Lahore Campus, 2022) Farzana Bashir; CIIT/FA20-RPH-045/LHR; Dr. Ishrat Sultana; LHR TP 8001
    The current energy crisis is at its peak, and traditional energy sources are inadequate to supply modern energy demand. Consequently, the energy storage technology that can sustain current requirements is in high demand. Batteries and supercapacitor are examples of electrochemical energy storage devices (EESDs) that have been developed for a long time as crucial force sources in our daily lives. Orange peel, banana peel, wheat straw, olive stone, pistachio shells, walnut shells, beech wood, and hard coal, among other waste biomass sources, are used to produce activated carbon (AC). Activated carbon is used in energy storage applications due to high electrolyte wettability, high reactivity, and high thermal stability. Non- porous carbons are generated by the environmentally friendly, cheap, and low-temperature method of hydrothermal carbonization. For un-activated carbon we take 20 g of corn hair fiber and make gel in 100 ml DI water material was placed in autoclave at 250 ºC for 16 h. Activated carbon and KOH was taken by the ratio of 1:4 respectively, then grinding it in mortar and pestle, heated at 700-800 ºC at the 3 ºC min-1 ramp in a horizontal furnace under a nitrogen flow environment and held at this temperature for 1h. Hydrothermal process and temperature pyrolysis results in increased content of carbon and its aromatic nature in activated carbon. The percent yield of Activated carbon obtained through this method is much higher than other methods. Raman spectroscopy and Fourier transform infrared spectroscopy were used to evaluate the sample and approximate its composition. Cyclic voltammetry and electrochemical impedance spectroscopy were used to explore the sample's electrochemical properties. CV and Specific capacitance show the enhancement of conductivity. The material has the highest specific capacitance 235 Fg-1.
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    Investigations on Silicon Dioxide Nanostructures for the Applications of TOPCON Solar Cells
    (2022) Sidra Abdullah; CIIT/FA20-RPH-012/LHR; Dr. Shahzada Qamar Hussain; LHR TP 7974
    Silicon has been considered the best material for the fabrication of solar cells due to its non- toxicity, abundance, high and stable cell efficiencies, and industrial technological approaches. In this project, silicon dioxide (SiO2) based nanostructures were synthesized using a solution- based sol-gel technique. Spin coater was used to deposit the thin films of SiO2 on a glass substrate. The surface morphology of SiO2 nanostructures was measured by using a scanning electron microscope (SEM). The structural analysis of SiO2 nanostructures was studied via X- ray diffraction (XRD) analysis. UV-Vis spectrophotometers were used to measure the optical properties of SiO2 thin films. The simulation was used to study the influence of SiO2 and other layers on the TOPCON solar cells
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    Electronic Structure and Photo-catalysis Properties of Hetero Bilayered Materials
    (Library Information Services, COMSATS University Islamabad, Lahore Campus, 2022) Humaira Rafique; CIIT/FA20-RPH-013/LHR; Dr. Farah Alvi; LHR TP 7976
    This thesis is dedicated to the synthesis of LiZnO and MgZnO based semiconductor materials for photocatalysis. As solar cell is an efficient device for clean energy production. To enhance the efficiency of such type of clean energy devices an efficient photocatalytic material is required for proper working. The efficiency of photocatalysis water-splitting reaction has been limited. However, to solve this issue we will develop a simple and novel reaction mechanism as well as an important need for stable and highly efficient catalytic materials. Therefore, in this research work LiZnO and MgZnO semiconductor materials was made by sol-gel method. To analyze the structural properties of the synthesized samples XRD has been carried out and find out one phases in LiZnO and MgZnO materials. By using RAMAN and UV spectroscopy, to detect vibrational, rotational, and other states in a molecular system and optical properties have been studied of materials respectively. From the graphs of electrochemical characterizations, we conclude that the best performance among two prepared samples is given by the sample MgZnO. The reason is that MgZnO behaves like a good photocatalyst as compared to that of LiZnO. Further DFT calculations was performed to study electronic structure, current density and optical properties of the material.
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    Synthesis of CeO2/NiFe2O4 Nanocomposites and their Photocatalytic Activity of Methyl Orange Dye under UV-Visible Irradiations
    (Library Information Services, COMSATS University Islamabad, Lahore Campus, 2022) ALI BASHEER; CIIT/ FA20-RPH-048/LHR; Dr. Muhammad Hammad Aziz; LHR TP 8003
    Using the hydrothermal technique CeO2/NiFe2O4 for exceptional photocatalytic activity, nanoparticles are fabricated. Methyl Orange dye according to its toxicity, color, and environmental hazards was used as aqueous pollutant source for photocatalytic experiment results. The synthesized nanoparticles were characterized by various techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), UV-visible spectroscopy, scanning electron microscopy (SEM). The photocatalytic activity of synthesized nanoparticles was studied by conducting the degradation of methyl orange under the visible light. PL spectra were verified for the recombination and separation time for the synthesized nanoparticles in different light regions. 88.57% of Methyl Orange was degraded in 120 min. The result attests to low cost, reusable and high efficiency photo catalyst for environmental remediation. The synthesize sample is easily separable using any external magnetic source. In addition, sample results show the shifting of absorption spectrum towards the visible region of light. FTIR and XRD results show the functional and cubic spinel shape photo catalysis formation. SEM images show the morphology of the sample. Reusability and stability experiment exhibit the miner reduction in catalyst efficiency percentage after five cycles. According to extraordinary applications the synthesize sample are used on large scale for Industrial Waste Water treatment process in future.
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    Experimental and Computational Studies of Perovskite Oxygen Carrier Materials for CO2 Separation
    (Library Information Services, COMSATS University Islamabad, Lahore Campus, 2022) USWA FIRDOUS; CIIT/FA20-RPH-009/LHR; Prof Dr. Rizwan Raza; LHR TP 7973
    This dissertation is dedicated to Experimental and Computational Studies of Perovskite Oxygen Carrier Materials for CO2 Separation.Energy is basic need of this hour. The combustion of natural sources like fossil fuels produce hazardous gases like CO2. The concentration of CO2 in air is the main cause of depletion of ozone layer and climate effects. To overcome this problem, Chemical looping combustion CLC is a very promising technique. In this project, we synthesize perovskite oxygen carrier materials for the separation of CO2.The proposed materials are Iron-based strontium manganese oxide (FeSrMnO3), where (x = 0.1, 0.3, 0.5 , 0.7 , 0.9 ) are prepared by using solid state reaction method. Different characteristics of perovskite oxygen carrier materials FexSr1-xMnO3 are studied in this project like X-ray’s diffraction (XRD), Raman spectroscopy, Fourier Transformation Infrared Spectroscopy (FTIR), Thermogravimetric analysis (TGA), Scanning electron microscopy (SEM) and some theoretical studies like Density Functional Theory (DFT). The XRD pattern of (FeSrMnO3), where (x = 0.1, 0.3, 0.5, 0.7, 0.9 ) represents the same pattern which is tetragonal with reference code JCPD NO: 00-051-1860. The average crystalline size is 946, 765, 780 ,550 and 642 respectively. Raman spectra of all samples FexSr1-xMnO3 show prominent bands at 132, 190, 432, 527, 648, 796, 895 and 980 cm-1 related to Fe-O vibration, symmetric stretching vibration of metal oxygen chain of Mn-O-Mn O, symmetric and asymmetric stretching vibration of Sr-O band, T2g mode, transverse, longitudinal and two phonons optical (2LO) modes. FTIR spectra of all samples of FexSr1-xMnO3 show the peaks at 608, 770 – 900, 968, 1078, 1173, 1365 , 1491 , 3500-4000 cm-1 vibrational modes of Sr- O, Mn-O stretching vibrations , Fe-O nanoparticles , vibrations among O-O bonding and OH-functional group or the presence of adsorbed water molecules. Surface morphology of prepared composite materials is studied by Scanning Electron Microscopy (SEM) (homogenous and porous structure). The DFT calculations of FexSr1-xMnO3 tells about the structure which shows both cubic and hexagonal, DOS (Electronic Density of states) tells about the properties of metals and we can find band gap of the material. The material shows metallic nature because no band gap is observed in prepared oxygen carrier material.
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    Mixed Former Effect on the Photo Physical Properties of Phospho Tellurite Based Glasses
    (Library Information Services, COMSATS University Islamabad, Lahore Campus, 2022) Tayyaba Yousaf; CIIT/FA20-RPH-005/LHR; Dr. Junaid Amjad; LHR TP 7970
    Phospho-Tellurite glass was prepared earth to study the network former mixing effect in the prepared glass. The glass was prepared by melt quench technique in an electrical furnace at a temperature of 1100 °C. Glass were made in palettes of 2mm in size. The prepared glass was then characterized by using Raman, FTIR and UV- VIS (Reflectance) Spectroscopy. Raman Spectra revealed that phospho-tellurite are suitable for Raman broadband Amplifiers. FTIR revealed the functional groups of glass and verified the presence of non-bridging oxygen atoms. Whereas UV-VIS (Reflectance) Spectra was used to calculate the band gap of prepared glass sample. When UV-Vis spectrum will be examined via various wavelength it will show the absorbance of one or more sample component. The crystalline phase available in material will be recognized by XRD technique and it also discloses the chemical structure. Absorption data will assist the calculation of band gap. To compute the spectroscopic and electronic properties we also aspire to achieve the computational simulation that will yield further awareness.
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    Study of Structural, Thermoelectric and Electrochemical Analysis of LaSrCoFeO Cathode Materials Prepared by Different Methods
    (Library Information Services, COMSATS University Islamabad, Lahore Campus, 2022) Khadija Imdad; CIIT/FA20-RPH-044/LHR; Dr. Muhammad Ashfaq Ahmad; LHR TP 8000
    World is moving towards renewable energy sources to avoid carbon dioxide emission causing global warming and climate change. Solid oxide fuel cells SOFCs are one of the best alternatives for energy production due to its maximum energy conversion and zero/low emission. To use biogas as a clean and high energy conversion, SOFC is the good option. However, there are still some complications that need to be addressed; one of the significant challenges, activity of SOFC at low temperature is decreased because of interfacial polarization obstructions and also oxygen reduction reaction (ORR). Thus, to improve the activity and ORR, Lanthanum based perovskite structured cathode materials were synthesized. The proposed materials were Lanthanum Strontium Cobalt Ferric oxide (La1−xSrxCo1−yFeyO3–δ (LSCF)), where x=0.3 and y=0.7. Samples were prepared by different methods such as: sol-gel method, co-precipitation method, solid state reaction method and ball milling method. The structural properties were analyzed through Raman, FTIR and XRD.UV visible analysis were also implemented to check the direct and indirect band gap of La0.7Sr0.3Co0.3Fe0.7O3-δ prepared by different methods. Electrical Impendence Spectroscopy was uses to check the conductivities of the prepared samples at different temperatures. Results revealed the Rhombohedral Structure of LSCF belongs to the R3c space group. FTIR Spectra shows the absorption peaks at 650cm-1, 656cm-1, 657cm-1, is due to the stretching vibration of Co-O/Fe-O in LSCF perovskite structure. The maximum conductivity was obtained 0.08 S/cm at intermediate temperature of LSCF which was prepared by Co Precipitation Method. This suggests that resistance lowers as temperature rises, leading to an increase in conductivity and ORR as well. La0.7Sr0.3Co0.3Fe0.7O3- δ, which was made using the co-precipitation method, has a direct band gap of 2.51 eV. This sample has the lowest band gap of all the samples made using various methods. AC conductivity is measured by four-point probe spectroscopy for the LSCF cathodes. The data obtained from four-point probe spectroscopy electrical conductivity for all prepared cathode sample is calculated At Intermediate temperature (500°C) material with different methods such as sol-gel, co- precipitation, solid state reaction and ball milling give maximum conductivity such as 0.049,0.0889,0.0250 and 0.0159 respectively. The La0.7Sr0.3Co0.7Fe0.7O3–δ has maximum conductivity of 0.0889 Scm -1 at 500 °C prepared by co-precipitation method. The maximum value of OCV and current for the prepared pallets are 0.53V and 0.011A respectively. Whereas the maximum value of current density and power density is 17.18mA/cm2 and 2.88mW/cm2 respectively at 600℃.