الفهرس 
Chapter 1 IntroductionOnly 14 pages are availabe for public view
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Abstract
One of the biggest challenges facing the planet and life is energy and the environment. As a result of the negative impact of fuel combustion on our environment, the search for clean and renewable energy solutions has received wide attention. Solar energy is one of the cleanest and most abundant renewable energy sources on our planet. Its energy flow is approximately 104 times the total global energy consumption. Therefore, solar energy harvesting has become the modern trend in research worldwide. One of the contemporary ways to convert solar radiation directly into electrical energy is via photovoltaic cells. At present, silicon solar cells constitute about 90% of the PV market due to their non-toxicity, an abundance of silicon in the Earth’s crust, and long-term stability. Despite this, obtaining full absorption of the entire solar spectrum requires large amounts of silicon which ultimately increases the cost of the product. Silicon and organic thin-film solar cells with a thickness of a few micrometers are a useful alternative way to reduce the amount of material and the manufacturing budget. Unfortunately, the low uptake of micro-solar cells makes them less efficient. In this regard, light trapping techniques through the active material of the solar cell are a promising technique for improving the performance of thin-film solar cells. This can be achieved by increasing the length of the optical path within the absorber layer. Several technologies such as plasmonic structures, photonic crystals, periodic grids, and nanowires have been used to develop the efficiency of solar cells.
In this research work, a comparison between organic and silicon solar cells and an attempt is made to increase the efficiency with the trapezoid as a light diffraction . In addition, a crystalline silicon thin-film solar cell (c-Si TFSC) with a trapezoidal grating is newly introduced and analyzed. The three-dimensional (3D) finite-difference time-domain (FDTD) method is employed to optimize the geometrical parameters of the trapezoidal grating and hence maximize the light absorption. The proposed trapezoidal grating TFSC offers an optical ultimate efficiency (η) of 32.3%, with an enhancement of 81% relative to the conventional TFSC. The light absorption enhancement within wavelength range (300–1100 nm) is based on the diffraction grating, which supports Bloch modes through the suggested solar cell. The electrical characteristics of the proposed design are also studied using the finite-element method. The cell doping concentration, junction thickness, and recombination process are also investigated to further enhance the power conversion efficiency (PCE). The reported design offers a short circuit current density J_sc of 24.8 mA/cm2 and PCE of 12.5% with an improvement of 83% over the conventional TFSC.