Ahmed Farouk Al-Hossainy

Synthesis, spectral, thermal, optical dispersion and dielectric properties of nanocrystalline dimer complex (PEPyr–diCd) thin films as novel organic semiconductor

Dimer complex PEPyr–diCd (5a) has been prepared by reacting CdCl2⋅2.5H2O with 1,1′-bis(diphenylphosphino)ethyl-6-methyl-3-(pyridin-2-yl)-1,4-dihydro-pyridazine tungsten tetracarbonyl PEPyr (4a) as bipyridine ligand. The structural properties of PEPyr–diCd complex were characterized on the basis of elemental analysis (EA), Fourier transform infrared spectra, fast atom bombardment-mass spectrometry, thermogravimetric/differential thermal analysis, and 1H nuclear magnetic resonance spectroscopy. The crystal is orthorhombic, space group Pbca. Cd(II) metal in PEPyr–diCd organic semiconductor complex coordinated with two N of the PEPyr and three Cl − (one terminal and two bridging). The micro-structural properties of the films were studied via X-ray diffraction, and scanning electron microscopy. The as-deposited films were annealed in air for 1 h at 150, 200, and 250 ∘C. An average transmittance ≥ 70% for PEPyr–diCd complex at higher wavelength ≥ 800 nm was observed. In UV spectrum, the transmittance increases followed by a sharp decrease at wavelength 700–750 nm within visible range. The results of the absorption coefficient were determined to find the binding energy (EB) of PEPyr–diCd organic semiconductor complex as 0.242 and 0.47 eV, respectively. Refractive index (n) and absorption index (K) of PEPyr–diCd complex were calculated. Moreover, the dispersion parameters such as dispersion energy, oscillator energy, dielectric constant, and dissipation factor were determined. The oxidation of the imino-phosphine derivatives were examined using cyclic voltammetry in methylene chloride solvent. The cyclic voltammogram of PEPyr–diCd (5a) organic semiconductor appears to have two quasi-reversible oxidations at 543 and 441 mV. The obtained results indicate that the PEPyr–diCd organic semiconductor thin film is a good candidate in optoelectronic devices based on its band gap and dispersion parameters.

Facile synthesis and fabrication of a poly(ortho-anthranilic acid) emeraldine salt thin film for solar cell applications

Poly(o-anthranilic acid) emeraldine salt (PANA-ES) as a conjugated semiconductor polymer has been synthesized in an acidic medium based oxidative polymerization route. The identification of the PANA-ES powder has been carried out using the following techniques: FT-IR and UV-Vis. SEM has been used to investigate the morphology of the resulting PANA-ES powder. The structural properties of the resulting nanostructured PANA-ES thin film have been investigated by X-ray diffraction (XRD). The analysis of the spectral behavior characteristics of the nanostructured PANA-ES thin film, in the absorption region, displayed a direct and indirect allowed transition, and the fundamental energy gaps were estimated as (1.89, 3.24 eV) and (2.35, 4.06 eV), respectively. A hybrid (polymer/inorganic) heterojunction device built on PANA-ES (deposited by the spin coating technique onto a p-Si single crystal wafer) was fabricated. The dark I–V characteristics were determined at different temperatures in the range from 298 to 386 K of the Au/PANA-ES/p-Si/Al heterojunction diode. The device showed rectification behavior and an ideality factor of 85 at ±2 V and 3.229 determined at room temperature. Under the following different light intensities: 10.1, 15.3 and 20.5 W m−2, the Au/PANA-ES/p-Si/Al showed photovoltaic performance data with a short circuit current (Isc) and open circuit voltage (Voc) of (0.09 mA 1,41 mV), (0.16 mA, 176 mV) and (0.26 mA and 211 mV), respectively. The filling factor (FF) and electrical conversion efficiency (η) of the Au/n-PANA-ES/p-Si/Al device were found to be 0.205 and 6.07%, respectively.