Yazar "Yakuphanoglu, F." seçeneğine göre listele

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    An experimental optimization study for concentration and laser power effects in the fullerene-C60 and azo dye doped guest-host liquid crystal systems
    (Elsevier Science Bv, 2009) Okutan, M.; Koysal, O.; San, S. E.; Yakuphanoglu, F.
    The current-voltage characteristics of a famous guest-host liquid crystal system have been investigated under dark and laser illumination conditions. Dependency of current modulation with respect to concentration and laser power gives some optimization possibilities and estimations on the reorientation mechanisms of the liquid crystals. The current-voltage character of pure E7 is almost unchanged with laser pumping, while the fullerene and dye doping are enhancing effects in their individual and collective usage. The negative resistance effect was observed for some certain concentrations of the dye and C-60, and this peculiarity is shown to be switched with laser illumination. The mobility of the doped LC samples was calculated by transient current measurements and its dependency on the dye concentration and the laser power was investigated. It is evaluated that the effect of methyl red is a critical parameter in photoconductivity applications of liquid crystals. (c) 2009 Elsevier B.V. All rights reserved
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    Silicon based photodetector with Ru(II) complexes organic interlayer
    (Elsevier Sci Ltd, 2019) Karabulut, Abdulkerim; Dere, A.; Dayan, Osman; Al-Sehemi, Abdullah G.; Serbetci, Z.; Al-Ghamdi, Ahmed A.; Yakuphanoglu, F.
    In present work, the electrical properties and illumination effects were investigated for the silicon based photodetector with organic Ru(II) complexes interfacial layer. The current-voltage (I-V) and capacitance/conductance-voltage (C/G-V) measurements were analyzed to determine electrical and photoelectrical properties under dark and different solar light intensity conditions. The reverse bias current values under light conditions were higher than dark conditions, and this situation demonstrates that the fabricated device displays a photo conducting behavior. Besides, some crucial electrical parameters such as series resistance, barrier height and ideality factor values of prepared device were calculated by using current-voltage measurements. The ideality factor and barrier height values of fabricated device were calculated as 9.42 and 0.59 for dark condition. Besides to these experiments, transient photocurrent and photo-capacitance/conductance were also investigated under different light conditions. It was determined from transient measurements that the fabricated device has a high sensitivity to light. The photoresponse of the diode was determined to be around 4479 +/- 1.9 under 100 mW/cm(2 )illumination. The examined C/G-V characteristics of the fabricated device strongly depend on voltage and frequency. The analyzed results suggest that the fabricated Al/Ru(II) complexes/p-Si/Al device can be used in rapidly developing optoelectronic applications, especially for the organic materials-based photodetector technology.
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    Öğe
    The photodetection properties of a ruthenium electro-optic device for organic material-based device industry
    (Elsevier, 2023) Imer, Arife Gencer; Dere, Aysegul; Kaya, Esra; Al-Sehemi, Abdullah G.; Dayan, Osman; Al-Ghamdi, Ahmed A.; Yakuphanoglu, F.
    The electrical properties and effect of illumination on the photodetection properties were investigated for the fabricated device with Ru(II)-pydim complex interface layer. The Ru(II)-pydim interface was deposited by spin coating technique on a p-silicon substrate. The electrical and optoelectrical parameters of photodiode were analyzed via the current-voltage (I-V), capacitance/conductance-voltage (C/G-V) measurements under dark and different illumination power. The fabricated device has good electrical parameters such as the rectification ratio of 2.726 x 104, the ideality factor of 1.328, and barrier height of 0.805 eV under the dark condition. The current values of the device with Ru(II)-pydim interface at reverse bias were strongly dependent on the illumination intensities, confirming its photoconduction behavior. The I-V measurements under different solar illuminations present that the electro-optic device with Ru(II)-pydim complex as an interface has good photodiode parameters with the responsivity of 131 mA/W, and the detectivity of 1.63 x 1011 Jones at 100 mW/cm2. The photo transient measurements demonstrate that the Ru(II)-pydim complex based photodiode presents the desired photo-switching property. Therefore, the prepared Ru(II)-pydim based device can be used for electro-optic and photonic applications, particularly in the rapidly developing organic material-based device industry.