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

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

Effect of fluorosubstitution on the structure of single crystals, Effect of fluorosubstitution on the structure of single crystals,thin films and spectral properties of palladium phthalocyanines

In this work, the crystalline structure of single crystals grown by vacuum sublimation of unsubstituted palladium phthalocyanines (PdPc), its tetrafluorinated (PdPcF4) and hexadecafluorinated (PdPcF16) derivatives have been investigated using X-ray diffraction measurements. Two crystalline phases have been identified for PdPc; the molecules in both phases crystallize in stacks with herringbone arrangement in the monoclinic space groups (C2/c for -PdPc; P21/n for -PdPc). Both PdPcF4 and PdPcF16 crystallize in the triclinic P-1 space group, forming stacks of molecules in columnar arrangement with molecules in adjacent columns are aligned parallel to one another. X-ray diffraction measurements have also been used to elucidate the structural features and molecular orientation of thin films of PdPc, PdPcF4 and PdPcF16, grown by organic molecular beam deposition at different substrate temperatures. The effect of fluorosubstitution on UV-visible optical absorption and vibrational spectra of palladium phthalocyanine derivatives is also discussed

Heterostructures Based on Cobalt Phthalocyanine Films Decorated with Gold Nanoparticles for the Detection of Low Concentrations of Ammonia and Nitric Oxide

This work is aimed at the development of new heterostructures based on cobalt phthalocyanines (CoPc) and gold nanoparticles (AuNPs), and the evaluation of the prospects of their use to determine low concentrations of ammonia and nitric oxide. For this purpose, CoPc films were decorated with AuNPs by gas-phase methods (MOCVD and PVD) and drop-casting (DC), and their chemiresistive sensor response to low concentrations of NO (10–50 ppb) and NH3 (1–10 ppm) was investigated. A comparative analysis of the characteristics of heterostructures depending on the preparation methods was carried out. The composition, structure, and morphology of the resulting hybrid films were studied by X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma atomic emission (ICP-AES) spectroscopy, as well as electron microscopy methods to discuss the effect of these parameters on the sensor response of hybrid films to ammonia and nitric oxide. It was shown that regardless of the fabrication method, the response of Au/CoPc heterostructures to NH3 and NO gases increased with an increase in the concentration of gold. The sensor response of Au/CoPc heterostructures to NH3 increased 2–3.3 times compared to CoPc film, whereas in the case of NO it increased up to 16 times. The detection limits of the Au/CoPc heterostructure with a gold content of ca. 2.1 µg/cm2 for NH3 and NO were 0.1 ppm and 4 ppb, respectively. It was shown that Au/CoPc heterostructures can be used for the detection of NH3 in a gas mixture simulating exhaled air (N2—74%, O2—16%, H2O—6%, CO2—4%)