Browsing by Author "Karacali, Tevhit"

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The Influence of Annealing Temperature and Time on the Efficiency of Pentacene: PtCDI Organic Solar Cells
(Elsevier Science Bv, 2017) Biber, Mehmet; Aydogan, Sakir; Caldiran, Zakir; Cakmak, Bulent; Karacali, Tevhit; Turut, Abdulmecit
In this study, fabrication of a polycyclic aromatic hydrocarbon/Perylene Tetracarboxylic Di-Imide (PTCDI), donor/acceptor solar cells are presented using physical vapour deposition technique in a 1000 class glove box. An ITO/PEDOT:PSS/Pentacene/PTCDI/Al (ITO = Indium Tin Oxide and PEDOT:PSS = poly(3,4-ethylene dioxythiophene) polystyrene sulfonate) solar cell has been obtained and the power conversion efficiency, PCE (eta) of about 0.33% has been obtained under simulated solar illumination of 300 W/m(2). Furthermore, the effects of annealing temperatures (at 100 and 150 degrees C) and of annealing (at 100 degrees C) times for 5 and 10 min. on the power conversion efficiency, eta of the solar cells have also been investigated. In general, it has been seen that the thermal annealing deteriorated the characteristics parameters of Pentacene/PTCDI solar cell such that both fill factor, FF and eta decreased after annealing and with increase of annealing time. Atomic force microscopy (AFM) images showed that the phase segregation and grain size increased and the surface roughness of Pentacene film decreased and these effects reduced the eta value. The eta values of the solar cell have been determined as 0.33%, 0.12% and 0.06% for pre-annealing, annealing at 100 and 150 degrees C, respectively. (C) 2017 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license
A Novel Proton-Exchange Porous Silicon Membrane Production Method for MDMFCS
(TÜBİTAK Scientific & Technological Research Council Turkey, 2020) Gor Bolen, Meltem; Karacali, Tevhit
This study introduces a new production method to use as a porous silicon-based proton exchange membrane for mu DMFCs. In this respect, EIS, fuel crossover test, and fuel cell performance test at the mu DMFCs sample cell are performed at room temperature on a porous silicon-based membrane that was produced for passive mode mu DMFCs as a proton exchange membrane. The reason for performing the fuel crossover test is to ensure the silicon opened pores along the silicon wafer and to examine the fuel permeability of the membrane. The fuel crossover test shows that the fuel cell provides energy for about 60 min with a 50 mL fuel. EIS reveals proton permeability of proton exchange membrane. The calculated value of the conductivity of the membrane is 0.0016 S/cm. OCV of the system is 0.4V, whereas values (with highest power density is 0.1 mW/cm(2) and with the highest current density is 0.39 mA/cm(2)) are low. However, porous silicon is not a natural proton conductor. Hence, these values can be increased by different ways such as porous silicon functionalized, or serial connection of fuel cells. On the other hand, the value of OCV is consistent with the previous studies. In sum, this study presents a simple, cost-effective, and short time-consuming method for the production of porous silicon as proton-conducting membrane behavior.