Burak Kadem

Hybrid materials of pyrene substituted phthalocyanines with single-walled carbon nanotubes: structure and sensing properties

Hybrid materials of single walled carbon nanotubes (SWCNT) were obtained by their non-covalent functionalization with asymmetrically polyoxyethylene substituted phthalocyanines (MPc-py (M = Cu, Co, 2H)) bearing one pyrene group as a substituent. The attachment of MPc-py molecules onto the SWCNT surface have been confirmed using Raman spectroscopy, SEM, TEM and thermogravimetric analysis. The pyrene substituents were introduced to the phthalocyanine macrocycle in order to improve π–π interaction between the MPc-py and SWCNT. The effect of the central metal on the formation and sensor properties of the MPc-py within the hybrids has been verified. It has been shown that the electrical response of the hybrid films to ammonia vapor in the concentration range of 10–50 ppm changes in the following order CuPc-py > CoPc-py > H2Pc-py, which was found to be in good correlation with the amount of phthalocyanine molecules adsorbed onto the SWCNT walls, as estimated by thermogravimetric analysis (TGA).

The effects of organic solvents and their co-solvents on the optical, structural, morphological of P3HT:PCBM organic solar cells

The effect of different solvents on the optical, structural, morphology and solar cell performance of P3HT:PCBM based devices were carried out using UV-visible absorption spectroscopy, XRD, AFM, SEM, electrical conductivity as well as current density-voltage (J-V) measurements in dark and under illumination. Chloroform (CF), chlorobenzene (CB), di-chlorobenzene (DCB), and their mixtures (DCB:CB, DCB:CF and CF:CB) in the ratio 1:1 were used as solvents to produce active layers of P3HT:PCBM heterojunctions. UV-visible absorption spectra have demonstrated different absorption intensities subject to the used solvents as well as a decrease in the optical bandgap from around 1.9eV to 1.8eV. AFM and SEM images gave an indication on the films’ morphological properties, which have exhibited different topographies due to the used solvent. The electrical conductivity as well as the dark J-V characteristics were analysed using Richardson-Schottky model as well as space charge limited conduction theory to evaluate the...

The effects of solvent treated PEDOT:PSS buffer layer in organic solar cells

Various treatments on the PEDOT:PSS films were carried out to investigate it’s influence on the conductivity, morphology, transmittance and the corresponding impact of the performance of the organic photovoltaic devices based on the PCPDTBT:PCBM and P3HT:PCBM blends. These processing including doping PEDOT:PSS with DMF and ME solvents and exposing these films to the vapor of DMF and ME solvents, separately. A considerable enhancement of the conductivity and transmittance of PEDOT:PSS was observed after doping solvent into the PEDOT;PSS solution followed by solvent treatment through exposing these films to solvents environment. The best organic PV doped devices based on either PCPDTBT:PCBM or based on P3HT:PCBM with power conversion efficiency were 2.93% compared to 1.87% for the pristine PV devices or 2.79% compared to 1.77% for the pristine devices, respectively. The conductivity improvement was highly influenced by solvent treatment.

Study of some mechanical properties of PVA/TiO 2 composite at different ultrasonic frequencies

The PVA/TiO2 composite polymer membranes were prepared by a solGel casting method, the weight of PVA is constant (1gm) while the TiO2 powder weights were (0.01, 0.02, 0.03, 0.04, 0.05) gm, the density of the samples were measured by the weight method. In order to evaluate the mechanical properties of PVA/TiO2 composite the ultrasonic measurements were performed at the composites these properties are ultrasonic velocity, compressibility, acoustic impedance and bulk modulus at different frequencies (25,30,35,40) kHz , another acoustic mechanical properties were measured and calculated at a same time such as the ultrasonic wave amplitude before and after absorption by composite were measured using oscilloscope, then we calculated absorption coefficient and transmittance, shear viscosity , relaxation time and relaxation amplitude. It was found that there is significant relationship between ultrasonic velocity and material properties also results show that adding TiO2 effect on the absorption of the ultrasonic waves inside the composites.