Physical Sciences and Mathematics Commons^™

Fabrication And Characterization Of Perovskite Structures For Solar Cell Applications, Asma Obaid Said Al Ghaithi

Physics Theses

Solution-processing organic–inorganic hybrid perovskites have emerged as new generation and promising light-harvesting materials for photovoltaic technology and photonic applications such as solar cells, light emitting diodes and laser. The aim of this thesis is to boost the power conversion efficiency of planer perovskite solar cell by either using perovskite structure layer, or by doping perovskite thin film with metal ion to enhance the morphological, structure and optical properties of the perovskite thin film.

The first proposed perovskite layer is based on CH₃NH₃PbBr₃ and was fabricated using one step self-assembly method. The method is appropriate to produce CH₃NH₃PbBr₃ microstructures in form …

Simulation Of T2 Mri Relaxation Enhancement By Magnetic Nanoparticles, Yahia Adeeb Tawfiq Hamdan

Physics Theses

The effect of high concentration of magnetic nanoparticles (MNP) on Magnetic Resonance Imaging (MRI) transverse relaxation rates (R₂=1/T₂ and R₂*=1/T₂*) were studied using Monte Carlo (MC) simulations. Theoretical models assume that particle occupies a small volume fraction of the sample space. This work aims to test if available models based on Motional Averaged (MAR) and Static Dephasing Regimes (SDR) can still represent relaxation rates at large volume fractions. Furthermore, echo-time effects were tested on both gradient-echo and spin-echo sequences in order to examine if diffusion is involved. Findings will clarify if models need …

Power Series Solutions Of Nonlinear Partial Differential Equations: Applications In Nonlinear Physics, Laila Yahya Mohammed Al Sakkaf

Physics Theses

Obtaining analytical solutions for nonlinear partial differential equations (PDEs) is becoming a crucial role for many scientific researchers due to their importance in various physical systems. Many analytical and numerical techniques have been developed to solve PDEs, yet, there is no general applicable method for such equations.

In this study, we present an efficient iterative power series method for nonlinear boundary value problems that treats the typical divergence problem and increases arbitrarily the radius of convergence. This method is based on expanding the solution around an iterative initial point. Three nonlinear systems are considered here, the nonlinear Schrödinger equation (NLSE) …

Boron-Lined Nai Detector As An Efficient Alternative To He-3 Neutrons Detectors, Amira Mostafa Gaber Emam

Physics Theses

Helium-3 detectors are considered as the main component of most neutron detection systems in various nuclear fields because of their high thermal-neutron cross-section. But due to the worldwide shortage of He-3 gas after 2009 that led to a huge price increase, many researchers directed their efforts in order to find an efficient replacement. One of the proposed cost-effective alternatives is using an existing NaI detector covered with a thin layer of ¹⁰B to detect the gamma rays emitted from excited ⁷Li resulting from ¹⁰B(n,α)⁷Li reaction. İn this an MCNP model is developed to simulate He-3, …

The Effect Of Pressure And Interstitial Substitution On The Electronic Properties Of Molybdenum Disulfide Mos2, Wadha Khalifa Salem Rashed Alfalasi

Physics Theses

Molybdenum disulfide has some of graphene’s properties but has an edge over graphene as this new 2D nanomaterial has a band gap in its electronic structure, which is absent in graphene. The purpose of this thesis is to study the electronic properties of the promising Molybdenum Disulfide (MoS2) material in its bulk and monolayer forms by undertaking a systematic theoretical approach. We will mainly study the band gap, the density of states and the electronic charge distribution, which is considered as the most important electronic characteristics of semiconductors.

In this study, the density functional theory (DFT) – implemented in WIEN2k …