M.Phil / MS
Permanent URI for this collectionhttps://repository.cuilahore.edu.pk/handle/123456789/60
This collection archives the complete set of theses produced by students of the COMSATS University Islamabad, Lahore Campus.
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Item Effect of Silver Species on Luminescence of Lanthanide Ions incorporated with an Amorphous host material(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2020) Muhammad Yasir Ilyas; CIIT/FA18-RPH-038/LHR; Dr. Junaid Amjad; LHR TP 6344We studied the photonic characteristics of rare earth (RE) lanthanide samarium ions Sm3+ mixed with boro-phosphate glass. We prepared samples having composition69.9% [P2O5]—5% [B2O3]—25% [Na2O3]—0.1% [Sm2O3] by varying amount of AgCl. These Sm3+ mixed phosphate glasses was prepared by highly recommended melt-quenching method. Their physical, conductive,structural,chemical and photonic characteristics are recorded. The effect of Sm3+ doping on emission spectra (up-conversion or down-conversion) and lifetimes (over all behavior) was investigated .Samples were polished, passed through finishing process and crushed into powder for characterization i.e. UV visible, XRD, Raman spectroscopy photoluminescence spectrum PL & FTIR spectroscopy. The optical band gap energy (Eopt) direct and indirect allowed transitions. Density was measured by Archimedes method, which directly correlated SPR and LSPR. The irregular shapes of atoms of the glass samples were recorded from the X-ray diffraction pattern. The emission spectrum and other optical properties were recorded using photoluminescence characterization. The fluorescence spectra of Sm3+ ions exhibit emission transition of 4G5/2→6H13/2, &4G5/2→6H5/2 under514 nm excitation wavelengths by giving emission of green and red lights. When material is excited with 514nm light source it gives rise to down conversion from green light (514nm) to yellowish green (~530nm)&red light (~650nm).Down conversion of Green visible into both yellowish green &Red visible radiation could use in no of sundry applications in such as solid state lasers, LED/LCD displays, optical fibers, and fast optoelectronic devices The electronic/conducting properties of material were studied and calculated band gap using UV visible technique.Item Plasmonic interactions of silver nanoparticles with quantum dots embedded in borophosphate amorphous matrix: A photoluminescence study(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2020) Muhammad Zeshan Haider; CIIT/FA18-RPH-013/LHR; Dr. Junaid Amjad; LHR TP 6358We studied the photonic characteristics of Cadmium sulfide (CdS) with boro-phosphate glass. We prepared samples having composition 5% [P2O5]—70% [B2O3]—25% [Na2O2] 1% [CdS] by varying amount of AgCl. We mixed CdS with phosphate to prepare glasses by highly recommended melt-quenching method. Their physical, conductive, structural, chemical and photonic characteristics are recorded. The effect of CdS doping on emission spectra (up-conversion or down-conversion) and lifetimes (over all behavior) was investigated. Samples were polished, passed through finishing process and crushed into powder for characterization i.e., UV visible, XRD, Raman spectroscopy photoluminescence spectrum PL& FTIR spectroscopy. The optical band gap energy direct and indirect allowed transitions. Density was measured by Archimedes method, which directly correlated SPR and LSPR. The irregular shapes of atoms of the glass samples were recorded from the X-ray diffraction pattern. The emission spectrum and other optical properties were recorded using photoluminescence characterization. The fluorescence spectra of CdS exhibit emission transition of excitation wavelengths by giving emission of green and red lights. When material is excited with 514nm light source it gives rise to down conversion from green light (514nm) to yellowish green (~530nm) &red light (~650nm). Down conversion of Green visible into both yellowish green &Red visible radiation could use in no of sundry applications in such as solid-state lasers, LED/LCD displays, optical fibers, and fastItem Effect of TiO2 on the Structural, Mechanical and Optical Properties of Bioactive Glasses(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2020) Muhammad Zahid; CIIT/FA18-RPH-002/LHR; Dr. Junaid Amjad; LHR TP 6076The aim of the study presented in this thesis is to prepare bioactive sodium base borophosphate system with varying titanium content and fixed ratio of calcium oxide.This study aims to provide the structural, mechanical and optical analysis of such glasses to have a proper insight in the glass structure for better understanding of structure property correlation. Amorphous materials have open structure, so they can facilitate in the conduction. Samples were characterized by UV-Visible near Infrared (UV-Vis-NIR) spectroscopy. Understanding the novel application of bioactives borophosphate glass system in bone tissue engineering to be used as bone graft material. It is worth important to fabricate material with enhanced chemical durability, mechanical strength, sufficient thermal expension coefficient and bioactivity to further develop these biomedical devices. Present study provides the effect of structural, mechanical and optical properties of borophosphate glasses. Five Boro-phosphate samples with composition 70 B2O3 – 25 Na2O3 – 5 P2O5 – 1 CaO – x TiO2 where x=0 %, 0.1%, 0.3%, 0.5% and 1, weight % were prepared using melt quenching method. From the results of X-ray Diffraction (XRD), it was confirmed that the structure of the samples was amorphous and Na2O2 played an important role in assisting the glass formation. Amorphous materials have open structure, so they can facilitate in the conduction. Samples were characterized by UV-Visible near Infrared (UV-Vis-NIR) spectroscopy. From the results, direct and indirect energy band gaps were calculated. Direct energy band gaps were in the range 3.59 eV - 4.18 eV. Indirect band gaps were in the range 2.92 eV - 3.95 eV. Refractive index was also calculated which was in the range 2.19 - 2.42.Item Effect of TiO2 on the Structural, Mechanical and Optical Properties of Bioactive Glasses(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2020) Muhammad Zahid; CIIT/FA18-RPH-002/LHR; Dr. Junaid Amjad; LHR TP 7696The aim of the study presented in this thesis is to prepare bioactive sodium base borophosphate system with varying titanium content and fixed ratio of calcium oxide.This study aims to provide the structural, mechanical and optical analysis of such glasses to have a proper insight in the glass structure for better understanding of structure property correlation. Amorphous materials have open structure, so they can facilitate in the conduction. Samples were characterized by UV-Visible near Infrared (UV-Vis-NIR) spectroscopy. Understanding the novel application of bioactives borophosphate glass system in bone tissue engineering to be used as bone graft material. It is worth important to fabricate material with enhanced chemical durability, mechanical strength, sufficient thermal expension coefficient and bioactivity to further develop these biomedical devices. Present study provides the effect of structural, mechanical and optical properties of borophosphate glasses. Five Boro-phosphate samples with composition 70 B2O3 – 25 Na2O3 – 5 P2O5 – 1 CaO – x TiO2 where x=0 %, 0.1%, 0.3%, 0.5% and 1, weight % were prepared using melt quenching method. From the results of X-ray Diffraction (XRD), it was confirmed that the structure of the samples was amorphous and Na2O2 played an important role in assisting the glass formation. Amorphous materials have open structure, so they can facilitate in the conduction. Samples were characterized by UV-Visible near Infrared (UV-Vis-NIR) spectroscopy. From the results, direct and indirect energy band gaps were calculated. Direct energy band gaps were in the range 3.59 eV - 4.18 eV. Indirect band gaps were in the range 2.92 eV - 3.95 eV. Refractive index was also calculated which was in the range 2.19 - 2.42.