• MakaleYayıncıda açık erişim2024Scopus SJRQ2
    Controlling of electro-optical properties of cobalt phthalocyanine formed single chain polymer: Sudan III and nanographene based its composites

    Demirelli, Kadir; Barım, Esra; Tuncer, Hülya; Dere, Ayşegül; Canbay, Canan Aksu; Karaduman, Oktay; Al-Sehemi, Abdullah G.; Al-Ghamdif, Ahmed A.; Yakuphanoğlu, Fahretttin

    The synthesis of poly[4-(4-vinylbenzyl)oxy)phthalonitrile-co-styrene] [P(VBOPN5 %-co-St)] was carried out by free radical polymerisation at 60 °C. The successful formation of a green coloured single-chain polymer molecule with the formation of cobalt phthalocyanine (SCP-CoPc) was performed at 140–150 °C in the presence of dilute cyclohexanol. The characterization of SCP-CoPc was confirmed by FT-IR and UV/vis spectroscopic techniques. The absorption filtration process of the SCP-CoPc polymer/Sudan III composite was investigated. The introduction of Sudan III into the SCP-CoPc polymer matric strongly affected the optical transmission spectrum of the composite films. The optical transmission measurements of the SCP-CoPc/Sudan III thin film show a high absorption in the visible region (400–800 nm). In the SCP-CoPc/Sudan III composites, the optical band gaps (Eg1 and Eg2) of each of its components has changed significantly. The Eg1 and Eg2 were found to be between 1.90 and 2.83 eV, respectively. Depending on the sudan III content, a wide range from 600 nm to 730 nm indicates complete absorption filtration. The dc electrical conductivity and dielectric behavior of the SCP-CoPc/Nanografene (NG) 6 wt% nanocomposite increased with increasing temperature. From the dc conductivity plot, the Ea values of I. and II. regions were found to be 0.75 eV and 0.27 eV, respectively and it was found that the calculated activation energy obeyed the Arrhenius relationship. The refractive index and the optical permittivity of SCP-CoPc/NG 6 wt% have been estimated.

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  • MakaleYayıncıda açık erişim2024Scopus SJRQ1
    Photonic device application of a self-driven MXene based nanocomposite

    Demirelli, Kadir; Dere, Ayşegül; Barım, Esra; Tuncer, Hülya; Yakuphanoğlu, Fahrettin

    MXene based ternary composite photonic device was fabricated and characterized for the detection of different illuminations. The single chain polymer-cobalt phthallocyanine (SCP-CoPc) carrying metallised pthalocyanine macro ring was used as a polymer for the preparation of ternary composite. The Fourier Transform Infrared Spectroscopy (FT-IR), Transmission Electron Microscopy (TEM), Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX) were used to differentiate MXene/ZnO/SCP-CoPc composite prepared. The presence of Ti, C, O, Zn and Co elements in the structure of the composite was confirmed by EDX. The electrical properties of planar interdigital coated MXene/ZnO/SCP-CoPc (1:1:1 by wt) were investigated for photovoltaic application. The photo-generated carriers contribute to the current flow, and the linear photoconductivity behaviour in current measurements with different illuminations such as 20, 40, 60, 80 and 100 mW/cm2 indicates the possible photo device use of MXene/ZnO/SCP-CoPc nanocomposite. The photocurrent increased from 20 mA/cm2 to 100 mA/cm2 with the light intensity at 0.5 V was tuned from 28 to 280 μA. The forbidden energy gap (Eg) value of the MXene/ZnO/SCP-CoPc ternary composite from optical measurements was found to be 2.36 eV. Experimental results showed that the presence of SCP-CoPc and ZnO (zinc oxide) in the ternary nanocomposite increased the ε' and ε" values of MXene. The ε′ and ε″ of the ternary composite is 13.0, 26217 at 1 kHz and room temperature, respectively. The current-time results suggest that MXene based ternary composite photonic device is a self driven photodevice as the device can detect light without any external voltage bias.

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  • MakaleAçık Erişim2024Scopus SJRQ1
    Preparation of carbon dot/polyaniline composites as voltage based dielectric material for capacitor applications

    Coğalmış, Fatma Tuba; Demirelli, Kadir; Barım, Esra; Ük, Nida; Ünlü, Caner; Şenkal, Bahire Filiz; Dere, Ayşegül; Tuncer, Hülya; Yakuphanoğlu, Fahrettin

    Polyaniline-carbon dot (CD/PANI) composites were prepared via in-situ oxidative polymerization of aniline in the presence of carbon dots, with specific concentrations carefully controlled during synthesis. The composite was characterized using spectroscopic (FT-IR), morphological (TEM, SEM) and electrical methods. Impedance analysis was employed to investigate the transport behavior of charge carriers in the frequency range of 500 Hz to 10 MHz at 25 °C. This study provides a comprehensive analysis of the dielectric properties of the CD/PANI composite, including dielectric constant, dielectric loss, loss factor, AC conductivity, admittance, impedance, and Cole–Cole plots. The dielectric constant of the CD/PANI composite was 6.97 for 1 kHz at 0.5 V and 12.87 for 1 kHz at 5 V. The values indicate that the increase in the dielectric constant of nanocomposite with increasing voltage. This suggests that CD/PANI composite is a dielectric material whose dielectric constants are controlled by applied voltage. Notably, the dielectric constant increased with rising applied voltage and decreased with increasing frequency. Current-voltage (I-V) measurements revealed that the composite's dielectric parameters could be tuned by varying the applied DC voltage, suggesting its potential as a voltage-dependent dielectric (VDD) material for capacitor applications. Furthermore, the enhanced electrical conductivity indicates that the CD/PANI composite is a promising candidate for next-generation dielectric devices.

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  • MakaleAçık Erişim2018Scopus SJRQ3
    Ti doped amorphous carbon (Al/Ti-a:C/p-Si/Al) photodiodes for optoelectronic applications

    Aslan, Naim; Koç, Mümin Mehmet; Dere, Ayşegül; Arif, Bilal; Erkovan, Mustafa; Al-Sehemi, Abdullah G.; Al-Ghamdi, Ahmed A.; Yakuphanoglu, Fahrettin

    Electrochemical deposition technique was used to fabricate titanium doped amorphous carbon (Ti doped a:C) Al/Ti-a:C/p-Si/Al photodiode. The effects of illumination on the current–voltage (I–V) characteristics of the Al/a:C/p-Si/Al doped Ti diode for optoelectronic applications were investigated. The reverse current of the diode increased with the increasing illumination intensities when the bias voltage was applied. By using the forward bias I–V characteristics, the ideality factor (n) and barrier height (Φb) of Al/Ti-a:C/p-Si photodiode structure was found as 1,84 and 0,50 eV, respectively. In addition, the capacitance–voltage (C–V) and conductance–voltage (G–V) measurements of the diode were studied in the frequency range of 100 kHz–600 kHz. The measured values of the capacitance decreased with the increasing frequency. The photoelectrical properties of Al/Ti-a:C/p-Si/Al device indicates that the photodiode investigated in this paper has great potential to be used in optoelectronic device applications and in industry.

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