Thin films of chlorosubstituted vanadyl phthalocyanine: charge transport properties and optical spectroscopy study of structure

Electrophysics and structure of thin films of chlorosubstituted vanadyl phthalocyanine (VOPcCl16) were studied using complementary experimental and theoretical techniques. To study charge transport properties of the latter films, organic field-effect transistors were fabricated by physical vapor deposition. The device exhibited good air stability without any extent of degradation after a storage in air for two months. The charge carrier mobility was measured to be (2.00.1)×10-3 cm2 V–1 s–1. This value was rationalized by poor ordering of the VOPcCl16 films revealed with the use of polarization dependent Raman and UV-vis spectroscopies as well as by X-ray diffraction. Apart from this, we performed a detailed assignment of all intense bands in the vibrational spectra of VOPcCl16. To this end, the experimental IR and Raman data were complemented by quantum chemical (DFT) calculations at the B3LYP/6-311++G(2df,p) level of theory

Pyrene containing liquid crystalline asymmetric phthalocyanines and their composite materials with single-walled carbon nanotubes

In the present work we have studied the dispersion of single-walled carbon nanotubes in liquid crystalline asymmetrically substituted phthalocyanines (MPc, where M = = Cu, Co, and 2H) bearing one pyrene and six polyoxy groups as side chains. The influence of single-walled carbon nanotubes on the phase behavior of MPcs was investigated using X-ray diffraction, polarized optical microscopy and differential scanning calorimetry. It was demonstrated that the incorporation of small amounts of single-walled carbon nanotubes (≤ ≤ 1 wt.%) does not alter the MPc mesophases. The structural features and the sensor response of composite thin films of MPc with single-walled carbon nanotubes to ammonia vapor (10–50 ppm) was studied and compared with those of the films of pure MPc derivatives

Metal Ir coatings on endocardial electrode tips, obtained by MOCVD

The present work demonstrates the application of the Metal-Organic Chemical Vapor Deposition technique to fabricate metal iridium coatings onto the pole tips of endocardial electrodes. Using iridium (III) acetylacetonate as volatile precursor, the target coatings were successfully applied to the working surface of cathodes and anodes of pacemaker electrodes in the flow type reactor in hydrogen atmosphere at deposition temperature of 550°C. The coating samples were characterized by means of XRD, SEM, Raman- and XPS-spectroscopies. The formation of non-textured coatings with fractal-like morphology and 7-24 nm crystallite size has been realized. The electrochemical properties of the coatings were investigated by cyclic voltammetry and electrochemical impedance spectroscopy. The charge storage capacity values of the electrochemically activated samples were 17.0-115 mC·cm–2 and 14.4-76.5 mC·cm–2 for measurements carried out in 0.1M sulfuric acid and in phosphate buffer saline solutions, respectively. A comparison of some characteristics of the samples obtained with commercially available cathode of pacemaker electrodes is also presented

Effect of covalent and non-covalent linking of zinc(II) phthalocyanine functionalised carbon nanomaterials on the sensor response to ammonia

In this work, a comparative study of the sensor response of single walled carbon nanotubes (SWCNTs) and reduced graphene oxide (rGO) covalently and non-covalently functionalised with1-[N-(2-ethoxyethyl)-4-pentynamide]-8(11),15(18),22(25)-tris-{2-[2-(2-ethoxyethoxy) ethoxy]-1-[2-((2-ethoxy ethoxy)-ethoxy)methyl]ethyloxy}zinc(II) phthalocyanine (ZnPc) to ammonia is carried out. It was shown that in the case of SWCNT-based materials both covalent and non-covalent functionalisation with zinc(II) phthalocyanine leads to the increase of the sensor response toward NH3, while functionalisation of reduced graphene oxide causes a decrease in the response. At the same time both covalent and non-covalent linking of zinc(II) phthalocyanine leads to twofold decrease of the sensor recovery times. The sensor response of the carbon nanomaterial (single walled carbon nanotubes or reduced graphene oxide) hybrids covalently functionalised with zinc(II) phthalocyanine is several times higher than in the case of non-covalent linking of zinc(II) phthalocyanine to these nanomaterials, which is in good correlation with the number of zinc(II) phthalocyanine molecules adsorbed onto the SWCNT and rGO walls. © 2017 Elsevier B.V

Preparation of single wall carbon nanotube-pyrene 3D hybrid nanomaterial and its sensor response to ammonia

In this work, the structural features and sensor response toward ammonia of a three dimensional (3D) SWCNTs material covalently functionalised with 1,6-diethynylpyrene were studied. The target SWCNTs hybrid material was prepared by the reaction of azido substituted SWCNTs with the 1,6-diethynylpyrene containing double terminal alkyne groups via the azide-alkyne Huisgen cycloaddition (Click) reaction. The structure of the 1,6-diethynylpyrene compound was determined by different spectroscopic methods such as FT-IR, 1H-NMR, MALDI-TOF mass, fluorescence and UV–Visible, while its SWCNT-Pyrene 3D hybrid material was characterized by FT-IR, Raman, UV-Visible spectroscopies and thermogravimetric analysis. The morphology of the hybrid films was investigated by scanning electron microscope (SEM). The sensing performance of the SWCNT-Pyrene 3D hybrid material was studied against low-concentrations of NH3 in the range of 0.1-40 ppm by measuring changes in the films' conductivity at different levels of relative humidity. The reversible electrical sensor response toward ammonia was observed both in the case of SWCNT and SWCNT-Pyrene 3D hybrid films however the response values of SWCNT-Pyrene 3D hybrid film were higher than those of SWCNT

Thin films of fluorinated 3d-metal phthalocyanines as chemical sensors of ammonia: an optical spectroscopy study

A comparative study of the sensor response toward gaseous ammonia of hexadecafluorinated 3d-metal phthalocyanine (MPcF16, MCu(II), Co(II), Zn(II), Ni(II)) thin films was performed using complementary experimental (viz., surface plasmon resonance, SPR, and IR absorption spectroscopy) along with theoretical (density functional theory calculations, DFT) techniques. SPR measurements revealed changes of both thickness and optical parameters (refraction indices and extinction coefficients) of the MPcF16 films caused by adsorption of NH3. The MPcF16 species studied exhibited the following order of sensor response: ZnPcF16>CoPcF16≥CuPcF16>NiPcF16. A good correlation was found between the DFT calculated (B3LYP/6-311++G(2df,p)) binding energies, experimentally measured shift of the selected IR bands, and the optical sensor response. Apart from this, we performed a detailed assignment of all intense..

Study of the sensor response of spun metal phthalocyanine films to volatile organic vapors using surface plasmon resonance

tIn this work, thin films of chloroaluminium phthalocyanine (ClAlPc), fluoroaluminium phthalocyanine(FAlPc) and fluorochromium phthalocyanine (FCrPc), which are insoluble in conventional solvents, weredeposited by spin coating of their solutions in trifluoroacetic acid. The sensing response of these filmsversus acetic acid, three alcohols (methanol, ethanol, butanol) and three amines (methylamine, dimethy-lamine, trimethylamine) have been investigated using surface plasmon resonance as the sensing method.It has been shown that the sensor response of the investigated films decreases in the following order:acetic acid > alcohols > amines. The optical changes as monitored by SPR method have been used in con-junction with Fick’s second law of diffusion to determine the diffusion coefficients of analyte vapor duringthe films’ swelling process. The obtained results showed that the diffusion coefficients and the swellingcharacteristics of the films are dependent on the functional group of the phthalocyanine molecule andthe molecular size of the analyte

Tetrasubstituted copper phthalocyanines : correlation between liquid crystalline properties, films alignment and sensing propertie

Copper phthalocyanines (CuPc) containing alkylthio (-S(CH2)nCH3, n=7 and 15), alkyloxy- (-O(CH2)nCH3, n=7 and 15) and polyoxo (-O(CH2CH2O)3CH3 and -S(CH2CH2O)3CH3) substituents were synthesized and investigated to reveal the effects of substituents type (alkylthio, alkyloxy and polyoxo) and the type of the connecting heteroatom (oxygen or sulphur) on the mesogenic properties, films alignment and sensing behaviour. The liquid crystalline properties of these phthalocyanines were investigated by differential scanning calorimetry, polarizing optical microscopy and X-ray diffraction techniques. The structure and morphology of spun thin films of copper phthalocyanine derivatives were studied by the UV-Vis and Raman spectroscopies as well atomic force microscopy. The sensing properties of CuPc films were studied by the measurement of conductivity change upon interaction with ammonia in the range 10-50 ppm. All investigated films of CuPc derivatives display thermotropic columnar mesomorphism. It was shown that the films with polyoxo- (-O(CH2CH2O)3CH3 and -S(CH2CH2O)3CH3) substituents as well as with alkylthio -S(CH2)nCH3 (n=7) substituents, which are liquid crystalline at room temperature, form ordered films with a random planar alignment of columns. Their films exhibit the better sensor performance with the maximal sensor response for the films of CuPc containing (-S(CH2CH2O)3CH3) substituents

Thin films of unsubstituted and fluorinated palladium phthalocyanines: structure and sensor response toward ammonia and hydrogen

In the present work, we study and compare the structure and sensing properties of thin films of unsubstituted palladium phthalocyanine (PdPc) and hexadecafluorosubstituted palladium phthalocyanine (PdPcF16). Thin films of PdPc and PdPcF16 were obtained by the method of organic molecular beam deposition and their structure was studied using UV-visible spectroscopy, X-ray diffraction and atomic force microscopy techniques. The electrical sensor response of PdPc films toward ammonia and hydrogen was investigated and compared with that of PdPcF16 films. The nature of interaction between the phthalocyanines films and some gaseous analyte molecules has been clarified using Quantum chemical (DFT) calculations