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  • Küçük Resim
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    Halogen-substituted zinc(II) phthalocyanines: Spectral properties and structure of thin films
    (Elsevier, 2022) Klyamer, Darya; Bonegardt, Dmitrya; Krasnov, Pavel; Sukhikh, Aleksandr; Popovetskiy, Pavel; Khezami, Khaoula; Durmuş, Mahmut; Basova, Tamara
    In this work, the effect of the type of halogen substituents on the structure, morphology, and conductivity of thin films of zinc(II) phthalocyanines ZnPcHal4 (Hal = F, Cl, Br, I), deposited both by evaporations in vacuum and by a spin coating technique was studied. The influence of these different halogen substituents on the spectral properties of ZnPcHal4 derivatives was also investigated. For this purpose, the density-functional theory calculations of the vibrational spectra of ZnPcHal4 were carried out. It was shown that ZnPcHal4 (Hal = F, Cl) films obtained by physical vapor deposition (PVD) were polycrystalline and consisted of well-distinguishable rounded grains, whereas the introduction of the bulk bromine and iodine substituents led to the formation of amorphous films both in the PVD process and during spin coating deposition. The lateral d.c. conductivity of the films was shown to decrease in the order ZnPcCl4 > ZnPcF4 > ZnPcBr4 > ZnPcI4. The conductivity of PVD films, which were characterized by higher crystallinity and order, was higher than that of spun films. © 2022 Elsevier B.V.
  • Küçük Resim
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    Hybrid materials based on pyrene-substituted metallo phthalocyanines as sensing layers for ammonia detection: effect of the number of pyrene substituents
    (Elsevier B.V., 2023) Ivanova, Victoria; Klyamer, Darya; Krasnov, Pavel; Kaya, Esra Nur; Kulu, İrem; Tuncel Kostakoğlu, Sinem; Durmuş, Mahmut; Basova, Tamara
    In this work, the effect of the number of pyrene substituents in zinc(II) phthalocyanine molecules on the sensor properties of their hybrid materials with single-walled carbon nanotubes (SWCNT) is studied. For this purpose, hybrid materials of SWCNTs modified with five different trioxyethylenethio substituted zinc(II) phthalocyanines containing 0, 1, 2, and 4 methoxypyrene substituents in the phthalocyanine ring were prepared and characterized by Raman spectroscopy, scanning electron microscopy and inductively coupled plasma atomic emission spectrometry. The chemiresistive sensor response of the prepared hybrids toward low concentrations of ammonia (1–100 ppm) was studied to reveal the effect of the number of pyrene substituents in the phthalocyanine ring on the sensor performance of the hybrid materials. It was demonstrated that the hybrids with zinc(II) phthalocyanine bearing four methoxypyrene substituents exhibited the maximal sensor response to ammonia with the limit of detection of 0.4 ppm. The sensitivity of the hybrid materials to ammonia was shown to be much higher than to CO2, H2, H2S, CH4, ethanol, acetone, and dichloromethane vapors, however, an oxidizing gas such as NO2 was an interfering compound in the determination of ammonia. 1 ppm NO2 show the same absolute value of the response than 10 ppm NH3. The quantum-chemical calculations were performed to explain this effect as well as the dependence of the binding energy of substituted zinc(II) phthalocyanines with carbon nanotubes on the number of pyrene substituents.