الفهرس 
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Abstract
This thesis consists of two parts. Part I is a study of the structural and physical properties of an organic semiconductor namely 6 - (3, 4 Di methoxy phenyl)-1-methyl-3-oxo-2-phenyl-2, 3dihydro1Hpyrazolo[4,3-b]-5-carbonitrile and its application on devices fabrication (Si- based and perovskite solar cells). Part II deals with engineering of organic perovskite solar cells via studying variation of ambient processing parameters to control intermediate phases in mixed halide organic-inorganic perovskite (CH3NH3PbI3-xClx) film for efficient planar solar cells and the use of low band gap polymer as a hole-transporting material for efficient perovskite-based solar cells. 6-(3,4Dimethoxyphenyl)-1-methyl-3-oxo-2-phenyl-2, 3dihydro1Hpyrazolo[4,3-b]-5-carbonitrile, DMOPC, is a newly synthesized organic compound by a team in our institution. DMOPC in powder form showed polycrystalline structure with monoclinic crystal system. The deposited films showed nano crystallites dispersed in amorphous matrix. Optical constants of DMOPC films were estimated by using spectrophotometeric measurements of transmittance and reflectance at nearly normal incidence of light in the spectral range 190-2500 nm. The dependence of absorption coefficient on the photon energy, annealing temperatures and UV irradiation times was determined and the analysis of the results showed that the type of the optical transition in DMOPC films is indirect allowed one. The optical dielectric constants and dispersion parameters of DMOPC thin film are calculated and showed remarkable dependence on photon energy, UV exposure time and annealing temperatures. The electrical transport properties of Au/DMOPC /P-Silicon/Al heterojunction solar cell are studied. Also, the values of Rs and Rsh at room temperature are 4.48 k and 33.24 k, respectively. The values of barrier potential, , increase linearly with increasing temperature and the values of the ideality factor, n, decrease linearly with increasing temperature. The photovoltaic characteristics of Au/DMOPC/P-Si/Al heterojunction solar cell are studied under different illumination conditions using halogen lamp and we found that VOC and the maximum output power increase with increasing the illumination intensity. has maximum value at specific input power in the investigated input power range. FF decreases with increasing the input power to the device. Several methods of mixed-halide perovskite (CH3NH3PbI3-xClx) film crystallization in ambient air are studied with the aim of obtaining high crystallinity and complete conversion to perovskite phase in ambient air assisted with and without thermal annealing. We optimized the crystallization process of perovskite film by exposing the film to ambient air or partially exposure to air followed by thermal annealing or exposing it to air-flow at room temperature. Perovskite films were spin coated inside the N2 filled glove box and immediately were taken outside in air with 40% relative humidity (RH). Crystallized mixed-halide perovskite films obtained from different approaches were then used to fabricate planar perovskite solar cells with device structure as ITO/PEDOT: PSS/CH3NH3PbI3-xClx/PC60BM/Rhodamine/Ag. It was concluded that humidity plays an important role in crystallization of perovskite films in ambient air, but additional treatment could lead to improved perovskite crystallinity. Solution processed benzo dithiophene based polymer PBDTT-FTTE is used as a hole transport layer substituent to Spiro-OMeTAD. PBDT-FTTE doped with 3% DIO achieved photo conversion efficiency (PCE) of 11.6% same as Spiro-OMeTAD 11.6% but when using PBDTT-FTTE without doping it achieved PCE of 10.6.