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    Adsorption of Phthalocyanines on Stoichiometric and Reduced Rutile TiO2(110)
    (Electrochemical Soc Inc, 2020) Kilinc, Necmettin; Ozturk, Zafer Ziya; Berber, Savas
    We report ab initio density functional theory calculations for the metal-free phthalocyanine (H2Pc) and zinc phthalocyanine (ZnPc) molecules adsorbed on rutile titania TiO2(110) stoichiometric and reduced surface. The hybrid nanostructures that combine titania surfaces with organic molecules help to improve the applications for both the titania surface and the organic molecule. We determine the atomic structures for all possible adsorption sites through total energy calculations and atomic structure optimizations. We find that the surface oxygen atoms play a crucial role in determining the best adsorption position and adsorption energies. Charge transfer occurs from the phthalocyanine to the surface. The electronic structure of the hybrid system indicates the appearance of surface states in the energy gap of the bare surface. We univocally determined that these new states involve N atoms and are originated only from the surface atoms with no bulk contribution.
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    Electrical and NO2Sensing Properties of a Series of Liquid Crystalline Porphyrins
    (Electrochemical Soc Inc, 2020) Kilinc, Necmettin; Ahsen, Ali Sems; Ozturk, Zafer Ziya
    The electrical and NO(2)sensing properties of a series of porphyrin derivatives (PPC12, PPC16, ZnPPC12) were studied within wide temperature range from 293 to 423 K under the N(2)gas flow and in the frequency range from 1 kHz to 1 MHz for ac electrical measurements. The dc conductivities and the activation energies were found to be in the range of 10(-13)-10(-12)S cm(-1)at the room temperature and 0.46-1.03 eV respectively. The increased C number in the alkyl chain and addition of metal ion to the porphyrin causes a decrease in the conductivity. The ac conductivity was well represented by the power law form A omega(s). The s parameter depending on temperature was varied 0.79-1.2. The conduction mechanism for all porphyrins could be related to small polaron tunneling (SPT) model. As an application, the NO(2)sensing properties of ZnPPC12 were investigated depending on temperature.