الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Recently, a growing need for energy resources is notable, especially that the current traditional sources such as oil, gas and coal will all be depleted in the near future, and this is why efforts went to search for a new sources of energy, specifically those that are environmentally friendly and sustainable. Solar energy is considered one of the most important sources where studies have been focused on how to convert such energy into various other forms, specifically electric energy. Many studies have been done for the developments of the solar cells. It started in its traditional, based on a silicon single crystal, passing through polycrystalline cells of other semiconductors, ending with dye solar cells. The goal of dye solar cells development was to obtain a low-cost, simple-to-manufacture, and high-efficiency solar cell conversion for a long period of time. Therefore, this study is aimed to study the structural phases and electronic properties of the components of a dye solar cell based on Zinc oxide nanoparticles. Both ZnO pure and doped with different concentration of aluminum oxide as well as the natural turmeric dye- are the materials to be studied. Samples of zinc oxide nanoparticles were prepared with different concentrations of aluminum oxide (0.0, 0.5, 1.0, 3.0, 5.0 wt%) using a sole-gel method at different heat treatment (30, 400, 500, 600Co) for one hour. Phase change and electronic transfer processes for both ZnO and Al2O3/ ZnO matrices have been studied using nuclear magnetic resonance spectroscopy (NMR), X-ray diffraction (XRD), energy dispersed X-ray spectroscopy (EDS), differential scanning calorimeter (DSC), transmission electron microscopes (TEM) with electronic diffraction (EDP) as well as ultraviolet spectroscopy (UV-VIS) and photoluminescence spectroscopy (PL). The effect of doping and its concentrations, as well as the effect of thermal heat treatment (THT) at different temperatures, was recorded on the nature and properties of the ZnO and Al2O3 / ZnO nanoparticles. It was concluded that zinc oxide is characterized by having a confirmed crystalline characteristic. It is confirmed that the quantity and type of crystalline ZnO phases are affected by changing material structure and heat treatment temperature. The crystalline structure in the ZnO matrix is fully transformed into an amorphous one by introducing Al2O3 to ZnO. This finding was due to the development of the material structure through formation of non-bridging bonds (NBB). The NBB formation can reduce the unified and symmetrical structure of ZnO leading to the formation of the less orderlyAl2O3/ZnO network. On the other hand, the amorphous phases are converted into the crystalline (ZnAl2O4) one, especially in heat-treated ZnO-Al2O3 compositions. This was interpreted on the bases that the THT mechanism will allow the process of phase separation that leads to crystallization to take place. The structure and size of various crystals could be identified by both TEM and EDP microscopy. The 27Al NMR analysis showed a considerable change in chemical shift upon increasing Al2O3. Sample containing 1 w% Al2O3 contains defective AlO4 units. While sample containing 5 w% Al2O3 has a more shielded structure due to formation of strengthened Al4-O-Zn4 bonds. A spectral signature of 27Al NMR showed that the NBBs have also been evidenced in AlO4 groups. In addition, AlO5 can be recorded in the aluminum rich matrix. The electronic properties and the charge transitions have been studied by analyzing the absorption spectrum of ultraviolet spectra (UV) as well as the emission spectrum of the photoluminescence spectra (PL) for all pure and doped ZnO nanoparticle samples. The study of the ultraviolet spectra has shown the existence of similar broadband behavior extending in the range from 200 nm to 400 nm, in addition to the appearance of sharp peak which attributed to the electronic transition from deep energy levels within the valence band (V.B) to deep energy levels within the conduction band (C.B), associated with some modifications to the matrix. Analyzing the photoluminescence spectrum (PL) of turmeric solution dye with different concentrations, showed a characteristic absorption band at 425 nm, this increases in its intensity with increasing dye concentration. Photoluminescence measurements and its spectrum have been analyzed and characterized with two primary regions. The first blue range (200 nm - 485 nm) and the other is red region (485 nm-550 nm), which reflect the responsibility of vacancy oxygen (Vo) and interstitial zinc atoms (Zni). It was also observed from PL spectra the appearance of the green range. The latter occurs as a result of a decrease in the degrees of crystallization of samples of zinc oxide nanoparticles and the emergence of point defects resulting from vacancy zinc (Vzn). Based on this study, dye sensitized solar cell ZnO/0.5% Al2O3 could be manufactured at heat treated temperature of 500Co with different concentrations of natural turmeric (curcomin) dye (1.0, 2.5, 5.0, and 10.0mol %). It has an increase in the efficiency of the prepared dye sensitized solar energy to reaches its largest value at 2.5% of the chromium dye. More addition leads to efficiency decreases again by increasing the concentration of the dye, which may be due to blocking more electron transportation.