الفهرس 
Theoretical BackgroundOnly 14 pages are availabe for public view
Abstract
Summery
This thesis represents a theoretical and experimental study for physical properties of some organic compounds. This thesis consists of four chapters, conclusion and list of references.
The thesis begins with a short theoretical background about the field of computational physics, starting from the basic many-body problems to the Hartree-Fock (HF) and density functional theory (DFT). The Gaussian 09W and Gauss view 5.0 program package, basis sets, origin of molecular vibrations and IR spectroscopy. We also represent the theory of light absorption, UV/Vis spectroscopy, theory of charge transport process in organic semiconductors and finally the theory of organic photovoltaic solar cell.
Then it represented a brief overview of the experimental techniques used in this thesis. It describes the basic of the conventional thermal evaporation (vacuum deposition) techniques, the configuration of the sample preparation, the film thickness measurement methods, the techniques that used to determine the molecular structure, i.e. X-ray diffraction pattern (XRD) and Fourier transform infrared spectroscopy (FT-IR) techniques, the techniques that used to determine the optical properties usually the spectrophotometric measurement of transmittance (T) and reflectance (R) at normal incidence of light, the cyclovoltammetry technique, the technique used to determine the value of energy gap, and also the techniques that used to determine the electrical properties.
The results of a computational study for the molecular structure of 4-cyanopyranoquinolinedione (CPQ) and its structural properties are also represented. The equilibrium geometries, harmonic vibrational frequencies, thermo-chemical parameters, total dipole moment, HOMO-LUMO energies, ionization energy, electron affinity, global hardness, electronic chemical potential, global electrophilicity index, softness and also first order hyperpolarizability are calculated by DFT/B3LYP utilizing 6-31lG(d,p) basis set. Comparison of the vibrational frequencies calculated at B3LYP utilizing 6-311G(d,p) basis set with experimental values reveals that B3LYP/6-311G(d,p) gives reasonable deviations from the experimental values. The results showed that 4-cyanopyranoquinolinedione possesses a dipole moment of 11 Debye and HOMO-LUMO gap of 3.4 eV. X-ray diffraction results indicate that powder of the investigated compound has a polycrystalline nature with a triclinic structure.
We also represent the optical properties of 4-cyanopyranoquinolinedione: transmittance (T), reflectance (R), optical constants (n,k), absorption coefficient (α), molar extinction coefficient (ε_molar), oscillator strength (f), electric dipole strength (q^2), HOMO-LUMO gap, single oscillator energy (E_0), dispersion energy (E_d) and dielectric constant (ε_L). The values of the HOMO-LUMO gap is calculated using an optical method and cyclovoltammetry technique. The type of the optical transition responsible for the optical absorption is direct allowed transition. The refractive index showed an anomalous dispersion in the absorption region as well as a normal one in the transparent region. Some dispersion parameters, the real and imaginary parts of dielectric constant (ε_1 and ε_2), volume and surface energy loss functions (VELF and SELF) and real and imaginary parts of optical conductivity ( σ_1 and σ_2). of 4-cyanopyranoquinolinedione films are determined.
Finally the thesis represents the electrical properties of 4-cyanopyranoquinolinedione thin film by studying the dark and illumination (I-V) characterization of Au/CPQ/p-Si/Al heterojunction. The transport mechanism of the electronic charges are determined for the heterojunction in the forward direction in Au/CPQ/p-Si/Al heterojunction. Results showed that the RR was about 14.5 for room temperature. The determined values of Rs and Rsh are found to be 27 kΩ and 710 kΩ, respectively. At low forward voltages the transport mechanism is thermionic emission mechanism and at high voltage is space-charge-limited conduction (SCLC) mechanism. The junction shows a photovoltaic behavior with a maximum open-circuit voltage, V_oc, of 0.16 V, a short-circuit current density, I_sc, of 3.2 mA and a power conversion efficiency, η, of 1.42%.