تهمینه جلالی

Dye-sensitized solar cells (DSSCs) are a newer generation of solar cells that, although they have lower efficiency compared to silicon-based solar cells, have a high potential for improved efficiency. Due to their better cost-effectiveness, they can replace silicon-based solar cells in the market if their efficiency and stability increase. The design and development of DSSCs have involved not only experimental and laboratory work but also numerical modeling. The aim of this work is to design and numerically model dye-sensitized solar cells based on a nanostructured semiconductor layer with a wide bandgap (titanium dioxide) and zinc oxide as the electron transporter, N719 dye as the absorber layer, and PEDOT:PSS and P3HT as hole transport materials. In this research, the advanced software CAMSOL with extensive capabilities is used for the design of dye-sensitized solar cells, and the current-voltage characteristics and optical absorption of the cell are calculated, which are in agreement with experimental data.

In this research, the synthesis of plasmonic nanoparticles was carried out by chemical dissolution method in three steps. Then, Au@TiO2 and Au@SiO2 core-shell nanostructures have been investigated. These nanostructures were used as photoanode in dye-sensitized solar cells (DSSCs). Parameters such as short circuit current, open circuit voltage, fill factor and conversion efficiency of DSSCs were obtained. The cell in which Au@TiO2 synthesized with mercaptoacetic acid ligand is used, has the highest efficiency. The primary causes of this are the heightened near-field effect of gold nanoparticles (AuNP) and the creation of enhanced photocurrent due to plasmonics.

Crimean Congo Hemorrhagic Fever (CCHF) is a deadly viral infection (mortality rate between 3 and 30%) reported from more than 30 countries. The disease is common between humans and animals and can be transmitted through tick bites, contact with blood and secretions or carcasses of infected animals and humans. The aim of this study was to determine the prevalence of CCHF virus in ticks isolated from domestic livestock in rural areas of Birjand city in South Khorasan province. In this study, 390 livestock including 167 sheep, 205 goats, 9 cows and 9 camels were sampled in four villages (Nofarest, Hassanabad, Amirabad and Shaukatabad) of Birjand county. Eight species of hard ticks were identified, including Rhipicephalus sanguineus (21.9%), Hyalomma detritium (25%), Hyalomma marginatum (2.4%), Hyalomma anatolicum (0.8%), Hyalomma asiaticum (1.6%), Hyalomma dromedarii (43). %) And other Hyalomma (4.7%). The presence of virus was confirmed in 15.9% of the samples sent to the laboratory by reverse polymerase chain reaction (RT-PCR). the virus was observed in: Rhipicephalus sanguineus, Hyalomma detritium and Hyalomma asiaticum. The most infected hosts were sheep and goats, and the ticks caught were all from lowland areas. The villages of this region can be considered endemic for CCHF. Therefore, it is recommended to follow controlling and monitoring policies in the region more carefully.

By designing periodic structures of photonic crystals, electromagnetic waves can be reflected in a certain frequency range from their surface. Using the above feature, the emission of photons can be guided in the designed waveguide within the structure of photon crystal networks. One of the most important applications of photonic crystals is in the construction of logic gates. Therefore, in this paper, using the simulation method based on the numerical method of finite difference in time domain, the propagation of electromagnetic waves inside two-dimensional engineered photonic crystals is investigated and the structure of band gap and distribution of electric and magnetic fields in the structure of photonic crystal lattice is calculated. The results show that using the unique structure of the designed photonic crystal, which has defects in the lattice, the performance of the AND and NOT logic gates can be well observed.

Crimean-Congo Hemorrhagic Fever (CCHF) is a viral, acute, febrile, and hemorrhagic disease that causes significant death in humans. Crimean-Congo hemorrhagic fever virus has been isolated from different species of ticks, including 28 hard ticks and 2 soft ticks. The aim of this study was to determine the prevalence of CCHF virus in ticks isolated from domestic livestock in border villages of Sistan region in the north of Sistan and Baluchestan province. In this study, 54 livestock including 50 sheep, 3 goats and 1 cow in four villages (Choto, Nader Alamkhan, Millak and Sanjarani) from Sistan region were sampled. After identifying genus and species of ticks, the samples were examined for the presence of the virus genome by reverse polymerase chain reaction (RT-PCR).Acording to taxonomic ranks 2 genera and 3 species were identified, which include Rhipicephalus Sanguineous, Rhipicephalus (Boophilus) annulatus and Hyalomma anatolicum. The presence of the virus was not confirmed in any of the 50 tested samples. Our findings indicate that CCHFV may not circulating in the ticks of Sistan border villages. However, since Sistan and Baluchestan province is an endemic region for CCHF, more research is needed for a better understanding of CCHFV vectors in this region.

In this paper, the interaction of light with coupled metalic nanoparticles by different models are studied. To investigate nonlocal effects simple suggested model and hydrodynamical model are utilized. Metalic nanoparticles are simulated, by taking account nonlocal effects in simple model. Therefore metal is replaced by a thin composite layer on metal-dielectric interface. The simulation is done by finite element method. The extinction-cross section spectra of the desired structure comparison is calculated by local, nonlocal and simple model. Nonlocal models have blueshift regarding local model, for desired structure the blueshift of the first peak in the extinction cross section spectra is 0.19 eV. The extinction-cross section spectra of various separation distance of nanoparticles are shown. Furthermore, the influence of increasing nanoparticles radius on extinction-cross section is analyzed in details. The results reveal that by reducing nanoparticles radius or gap, surface plasmon peaks are increased, due to the stronger nonlocal response. In smaller radius, the blueshift is significantly larger by nonlocal model relative to local model.

Optical and magneto-optical responses of magnetophotonic crystals (MPCs) with a magnetic defect layer sandwiched between two dielectric Bragg mirrors have been investigated, which have potential application in integrated-optics devices. The Bragg mirrors are periodic multilayered films composed of SiO2 and Ta2O5 coatings. By introducing Ce:YIG magnetic defect layer, the enhancement of rotation angle and transmittance value, have been reported. By using of Finite Element Method (FEM), we have simulated the electric field profile in MPCs and investigated the effect of defect layer thickness on Faraday rotation angles. As a result of localization of light at magnetic defect layer and strong light-matter coupling in MPCs, the magneto-optical responses of these structures, are mostly increased near the PBG edges. The structure with a half wavelength optical thickness of defect layer is most suitable for practical applications.

We investigate the transmission behavior of photonic crystals power splitter by using improved 2D FDTD and MMP methods. The Comparison between experimental data and simulation results are discussed in TE polarization. In this study, the 60° photonic crystal power splitter is optimized, which is composed of InPGaAs/InP material and air holes. The photonic crystal waveguide bend transmission data was measured by End-Fire technique. This computational method can be applied to investigate photonic crystals with irregularly shape and different materials. Comparison between experimental data and two dimensional simulations is evident that the improved 2D FDTD simulation shows a very good agreement with the experimental data of the transmission properties.

In this paper، the Mutiple Multipoles method is employed to solve nonlinear eigenvalue problem and calculate band structure for a 2D photonic crystal. Band structure is calculated for both TE and TM polarizations. Simulation space is implemented for the first Brillouin zone by using physical properties such as rods radius، permittivity and susceptibility. To model fields inside and outside of object، Multipole centers were located around it and Bessel series inside the object is shown complex fields. We used Bloch theory to implement fictitious periodic boundary conditions for the first Brillouin zone. To validate the code، we simulated the band structure of a cubic lattice and compare the results with Plane Wave Expansion Method which illustrates the accuracy of the code. It is shown that this method can be applied to investigate photonic crystals with irregular shapes and different materials for different lattices such as cubic، trigonal and honeycomb. Furthermore it could be used for dielectric or dispersive material and experimental data. Numerical calculation shows that MMP method is accurate، fast and it can be used on Personal Computers.

The accuracy of improved two dimensional finite difference time domain method (2D FDTD) is verified by comparing with 3D FDTD method and experimental data. The optimized 60° photonic crystal waveguide bend، used in this study as a test case، is composed of InPGaAs/InP material and air holes and TE polarization is considered. The photonic crystal waveguide bend transmission data was measured by End-Fire technique. This computational method can be applied to investigate photonic crystals with irregularly shaped and different materials. Comparison of experimental data with two and three dimensional simulations، it is evident that the improved 2D FDTD simulation shows a very good agreement with 3D FDTD simulation and also with the experimental data of the transmission properties. The efficiency and simplicity of 2D FDTD makes this algorithm promising for simulation of photonic crystals on personal computers of reasonable speed. Since the improved 2D FDTD simulation has a high performance compared to its 3D counterpart and also could easily be run on PCs، the improved 2D FDTD simulation can be considered as a useful tool in studying، designing and improving photonic crystal devices.