Fatih Dumludağ

Synthesis, characterization and electrical properties of peripherally tetra-aldazine substituted novel metal free phthalocyanine and its zinc(II) and nickel(II) complexes

The novel phthalonitrile containing azine segment and its corresponding tetra aldazine substituted metal free- and metallo-phthalocyanines (Zn(II) and Ni(II)) were synthesized and characterized by IR, (1)H NMR, Mass, UV-Vis spectroscopy and elemental analysis and addition to these techniques for substituted phthalonitrile (13)C NMR have been used. In addition, dc and ac electrical properties of the films of these novel phthalocyanines were investigated as a function of temperature (295-523 K) and frequency (40-10(5)Hz). Activation energy values of the films of the phthalocyanines were calculated from straight portions of the Arrhenius plot (lnσ(dc)-1/T curves) as 0.70 eV, 0.93 eV and 0.91 eV for the films of metal free, nickel- and zinc-phthalocyanines, respectively. From impedance spectroscopy measurements, it is observed that bulk resistance decreases with increasing temperature indicating semiconductor property.

Characterization of Doped and Undoped CuO Nanoparticles

Undoped and doped with Ti, Cd and Zn CuO nanoparticles were obtained by precipitation method. The crystal structures of the CuO nanoparticles were characterized by X‐ray diffraction. Impedance spectroscopy (IS) and d.c conductivity (σd.c) measurements were performed on samples as a function of temperature and frequency (40–105 Hz.) to determine the electrical behavior of the nano powder. It was found that the Arrhenius graph of the samples consist of two linear regions and corresponding activation energies. The dependency of frequency exponent s on temperature and frequency suggests a conduction mechanism which is indication of hopping. The measured impedance spectra showed a furher semicircle at low frequencies for all temperatures. The low frequency semicirles in impedance spectra are attributted to the garin boundry effects.

Synthesis in water-free DMF, characterization, electrical, and gas sensing properties of bis(2-(2-aminoethylamino)ethanol)copper(II) dibromide

Abstract2-(2-Aminoethylamino)ethanol (L) reacts with cupric bromide in dimethylformamide to give a mononuclear complex of Cu(II) [L2Cu]Br2, with six-coordinate distorted octahedral geometry, in which two molecules of tridentate (N,N,O) ligand are involved. The structure was confirmed by spectroscopic methods, elemental and thermogravimetric analyses, and magnetic measurements. Optimization of possible configurations indicated the formation of the trans structure of the complex. Experimental results indicate that the investigated complex, bis[2-(2-aminoethylamino)ethanol] copper(II) bromide, behaves as a semiconductor in the studied temperature range of 298–388 K. Gas sensing properties of the film for the volatile organic compounds (VOCs): acetone, tetra-chloromethane, chloroform, ethanol, and methanol, were also investigated as a function of vapor concentration and temperature in dark. The film showed maximum sensitivity to tetrachloromethane and ethanol vapors at room temperature. Responses of the film to the tested gases are reversible.

Vic-dioxime complexes bearing carboxyester and picolyl amide functionality: synthesis, characterization, spectroscopy, electrochemistry, and electrical properties

We have synthesized a vic-dioxime, [(1Z,2Z)-bis(2-oxo-2-(pyridin-2-ylmethylamino)ethyl)-N’1,N’2-dihydroxyethanebis(imidothioate)] (LH4) via dimethyl 2,2′-(1,2-bis(hydroxyimino)ethane-1,2-diyl)bis(sulfanediyl)diacetate (LH2) and 2-(aminomethyl)pyridine by using the condensation technique. The formation of mononuclear (Ni(II), Cu(II)) and homodinuclear (LH)2(UO2)2(OH)2) complexes of LH2 and mononuclear Cu(II) and homotrinuclear ((LH)2M3, M=Cu(II) and Ni(II)) complexes of LH4 were also obtained simultaneously with metal:ligand ratios of 1:2, 2:2 and 1:2, 3:2, respectively. The structure of the dioxime and its complexes are proposed in accordance with the elemental analysis, NMR, UV-Vis, FT-IR, and MS-FAB spectral data. The voltammetric analyses of the complexes showed metal- and ligand-based signals. The redox chemistry of the complexes exhibited various oxidation states of the central metals of the complexes. DC and AC conductivity measurements were performed at room temperature under vacuum in the dark. I-V characteristics of the complexes showed ohmic behavior. AC conductivity of the homotrinuclear copper and nickel increased and impedance of the same complexes decreased with increasing frequency.Graphical Abstract

Bridged oxide nanowire device fabrication using single step metal catalyst free thermal evaporation

In this study, indium-tin-zinc-oxide (ITZO) and Zn doped In2O3 nanowires were directly grown as bridged nanowires between two heavily doped silicon (Si) electrodes on an SOI wafer using single step vapor–solid–solid (VSS) growth method. SEM analysis showed highly dense and self aligned nanowire formation between the Si electrodes. Electrical and UV response measurements were performed in ambient condition. Current–voltage characteristics of devices exhibited both linear and non-linear behavior. This was the first demonstration of bridged ITZO and Zn-doped In2O3 nanowires. Our results show that bridged nanowire growth technique can be a potential candidate for high performance electronic and optoelectronic devices.

Electrical and gas sensing properties of novel cobalt(II), copper(II), manganese(III) phthalocyanines carrying ethyl 7-oxy-4,8-dimethylcoumarin-3-propanoate moieties

The synthesis of metallophthalocyanines (M = Co, Cu, Mn) bearing four ethyl 7-oxy-4,8-dimethylcoumarin-3-propanoate moieties was performed. These novel compounds were characterized by elemental analysis, 1H-NMR spectroscopy, FT-IR, UV-vis and mass spectral data. DC and AC electrical properties of the films of metallophthalocyanines were investigated in the temperature range of 295–523 K. AC measurements were performed in the frequency range of 40–105 Hz. Activation energy values of the films took place between 0.55 eV–0.93 eV. Impedance spectroscopy measurements revealed that bulk resistance decreases with increasing temperature, indicating semiconductor properties. DC conductivity results also supported this result. Their gas sensing properties were also investigated for the vapors of Volatile Organic Compounds (VOCs), n-butyl acetate (200–3200 ppm) and ammonia (7000–56000 ppm) between temperatures 25–100 °C. Sensitivity and response times of the films for the tested vapors were reported. The results wer...

Response to Vapors of Volatile Organic Compounds of SnO2 Thin Film

This work presents effect of the vapors of Volatile Organic Compounds (VOCs) on sol‐gel derived undoped SnO2 thin film. SnCl4.5H2O was dissolved in ethanol. After the solution is stirred for two hours 3 ml glacial acetic acid were added into the solution. After the clear solution is obtained thin film of SnO2 was deposited by dipping method on glass substrate patterned with Interdigital Transducer (IDT). Final curing temperature was 573 K. Crystal structure of the film was investigated using X‐ray diffraction. Gas sensing properties of the film were determined by means of change in conductivity as a function of temperature and gas concentration. The film was tested for the vapors of ammonia, toluene, ethanol and water. The film was also tested for the CO. Gas concentrations were controlled by MKS mass flow controller. The film was tested between the gas concentrations of 0.25% and 18%. All measurements were performed between the temperatures of 293 K–573 K. The film showed good sensitivity to VOCs vapors ...

Alcohol Sensing Properties of Sol‐gel Derived TiO2 Thin Film

In this work, alcohol sensing properties of pure TiO2 thin film were investigated. TiO2 were deposited on glass substrate patterned with interdigitated transducer (IDT) by a sol‐gel dipping method. Precursor solution is prepared by dissolving of titanium(IV) n‐butoxide in methanol. Then glacial acetic acid was added into the solution. Final heating was performed at 773 K in air. Crystal structure of the film was investigated using X‐ray diffraction. Target gases were vapors of ammonia, methanol, ethanol, and isopropyl alcohol. The measurements were performed in the temperature range of 293 K and 523 K. Gas concentrations were kept in the range of 0.4%–18%. Response characteristics of the film were determined by means of change in dc conductivity as a function of gas concentration and temperature. During the measurements 1 volt was applied to the IDT. Gas concentrations were controlled by mass flow controller. The film showed good sensitivity to the target gases in the measurement range. The results showed...

Gas Sensing Properties of bis‐Phthalocyanine Thin Film

In this study, response of the cofacial bis‐ phthalocyanine film to vapor of Volatile Organic Compounds (VOCs) was investigated. Test gases were vapors of acetone, toluene, ethanol and ammonia. Measurements were carried out between the temperatures of 293 K–423 K. Bis‐phthalocyanine was dissolved in chloroform. Thin film of bis‐phthalocyanine was deposited by spraying method on glass substrate patterned with Interdigital Transducer (IDT). During the measurements 0.5 volts were applied to the IDT. Response characteristics of the film were determined by means of change in dc conductivity as a function of gas concentration and temperature. Gas concentrations were controlled by mass flow controller. Dry nitrogen was used as carrier gas. Vapor pressure of the VOCs was calculated using Antoine equation. Response characteristics of the film were determined in a wide range of gas concentration (0.25%–18%). The film showed good sensitivity to the VOCs vapors in the measurement range. The responses of the film were...

Effects of the Metal Electrode on Dielectric Constant of MgO Nanoparticles

In this study, effects of the metal electrode on dielectric properties of MgO nanoparticles were investigated. MgCl2.6H2O were dissolved in ethanol and aged for a long time under stirring. The particles were obtained by precipitation method. Crystal structure of particles was investigated using X‐ray diffraction. In order to determine the electrical properties of the MgO nanoparticles, metal electrodes were deposited onto both sides of the MgO pellets using thermal evaporation method in high vacuum (<10−6 mbar). Dc and ac electrical properties of two MgO pellets with different metal electrodes (Au and Ag) were determined under vacuum ambient as a function of temperature (293–523 K). ac electrical measurements were carried out between the frequencies 40 Hz–105 Hz. Activation energy values of the MgO pellets with different metal electrodes were calculated using the relation σdc = σoe−Ea/kT and from slope of the dc conductivity (σdc)—inverse of temperature (1/T) curve. Dielectric constant was calculated as a...