Aslan Çakır, M.; Yetim, T.; Bozkurt, Y.B.; Kovacı, H.; Çelik, A.

In this study, commercial titanium (Cp-Ti) was coated with a UV-curable film to improve the wearing and tribocorrosion performance of Cp-Ti. Wear tests were carried out under dry and simulated body fluid (SBF) test environments, and tribocorrosion tests were also performed in SBF. In tribocorrosion tests, a reciprocating test device coupled with open circuit potential and potentiodynamic polarization test monitoring system was used. SEM investigations showed that a polymeric film with a layer thickness of about 3–4 µm was deposited on Cp-Ti. It was also found that the Si element in the film considerably increased the hardness and improved the wear performance. According to tribocorrosion test results, the corrosion mechanism has significantly increased the wear rates. The wear resistance of the Cp-Ti surface was markedly enhanced by UV-curable treatment.

Boda, Muzaffar Ahmad; Bozkurt Çırak, Burcu; Demir, Zeynep; Çırak, Çağrı

Herein, equimolar hexamethylenetetramine (HMT) were used to couple chemical bath deposition (CBD) and electrode deposition (ED) techniques to decorate electrodeposited one-dimensional (1-D) ZnO nano-rods with wurtzite nano-spindles in the attempt of increasing surface area to fabricate efficient and cost-effective dye sensitized solar cell (DSSC) photo-anode. The resulting hybrid photo-anode offers an enhancement of 43% in photocurrent density than bare ZnO nano-rods. The corresponding augmentation in photocurrent response is attributed to comparative increase in crystallinity and considerable decrease in charge transfer resistance across the interface as being analyzed by X-ray diffraction and electrochemical impedance spectroscopy (EIS), respectively.

Çorlu, T.; Karaduman, I.; Galioglu, S.; Akata, B.; Yıldırım, M.A.; Ateş, A.; Acar, S.

We report the successful synthesis and characterization of Zn1−xCuxO (x = 0.05, 0.10, 0.15, 0.20) thin films prepared by a simple and facile Successive Ionic Layer Adsorption and Reaction (SILAR) method. The nitrogen monoxide (NO) gas sensing properties of the Zn1−xCuxO sensors were studied systematically. The sensors were proved to have acceptable responses towards 20 ppb NO gas. Zn0.90Cu0.10O exhibited improved sensing performance at operating temperature of 55 °C compared to other samples. To improve sensor selectivity, a molecular zeolite filter was coated on the Zn0.90Cu0.10O sensor. The gas sensing results showed that the selectivity of intergrown zeolite filter coated Zn0.90Cu0.10O sensor enhanced significantly compared to uncoated sensors.

Astam, Aykut; Akaltun, Yunus; Yildirim, Muhammet

Thin films of copper selenide were deposited onto glass substrates using SILAR method at room temperature and annealed at 573 K for an hour in nitrogen atmosphere. As-deposited and annealed films were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, Raman spectroscopy, and optical absorption measurements. X-ray diffraction studies revealed that annealing the films in nitrogen atmosphere led to conversion of the tetragonal Cu3Se2 phase to cubic Cu2-xSe phase. Scanning electron microscopy images showed a considerable change in the morphology of the films and energy dispersive X-ray analysis demonstrated a reduction in selenium content with annealing. Typical Raman spectra of copper selenide thin films were obtained from the as-deposited and annealed films. Using optical absorption measurements, direct band gap energies of Cu3Se2 and Cu2-xSe phases were found to be 2.72 eV and 2.15 eV, respectively.

Kilic, Bayram; Turkdogan, Sunay; Ozer, Oguz Can; Asgin, Mansur; Bayrakli, Ozge; Surucu, Gokhan; Astam, Aykut; Ekinci, Duygu

Dye-sensitized solar cells (DSSCs) provide a low cost alternative to the conventional solar cells due to their easy and inexpensive device fabrication steps. Generally, F:SnO2 (FTO) conductive glass with a thin layer coating of platinum (Pt) is used as a counter electrode (CE) in DSSCs. Since Pt is rare and therefore expensive metal, we were looking for a way to produce a new counter electrode based on graphene/iron pyrite (FeS2) thin films as an alternative to the Pt:FTO. In combination with a TiO2 mesoporous photoanode and an I3−/I- redox electrolyte, graphene/FeS2 CE based DSSC shows η=7.43% energy conversion efficiency under 1 sun illumination (100 mW/cm2, AM 1.5G) which is approximately 16.1% higher than conventional Pt CE (η=6.40%). External Quantum Efficiency (EQE) is found to be shifted upward when graphene/FeS2 is used as CE in the place of Pt CE. The excellent performance of the graphene/FeS2 CE makes it a very promising alternative to costly Pt in DSSCs.