Spectral studies of phthalocyanines (original) (raw)
Related papers
2000
The surface plasmon resonance spectroscopy is an optical technique that is capable of monitoring chemical and physical processes. It is sensitive to detect small changes of dielectric properties in a metal-phthalocyanine boundary. For this reason plasmon resonance phenomena have been used to characterize a number of different types of films. This work analyses the possibility of using the surface plasmon resonance phenomena in the detection of gas. Thin films of copper, lead and nickel phthalocyanines have been examined in the plasmon system from the point of view of their application to NO 2 sensors.
Optical investigations concerning layered metalphthalocyanine nanostructures affected by NO2
2000
The paper deals with investigations concerning the coefficient of optical transmission of selected metalphthalocyanine layers, viz. CuPc, NiPc, PbPc, FePc and CoPc by means of optical spectroscopy. The coefficient of transmission was investigated for phthalocyanine layers in the presence of atmospheric air and after the exposition of these layers to 100 ppm nitrogen dioxide. These investigations concerned wavelengths in the
Study on the UV-Visble of Ni-Phthalocyanine thin film Optical Properties
Thin films of Nickel Phthalocyanine (NiPc) are prepared of a base pressure of 10 -5 m bar using Edwards 306 system of thermal evaporation technique .The films are deposited on to glass substrate at various thickness (50, 265 , 350) nm. The optical properties and spectral behavior of NiPc films as a function of thickness were studied at room temperature using UV -Visible -NIR absorption spectra. Increase in thickness, leads to increase absorbance of films and shifts peak position of all bands towards low energy side of spectra. Direct allowed transitions near the sort absorption edges were observed. Present studies reveal that the optical energy gap of NiPc thin film is around (3.3-3.25) eV for direct energy band gap respect to B bands, and around (1.68-1.63) eV for direct energy band gap respect to Q bands. The UV-Visible bands of Ni-Phthalocyanine are broadened and overlap in the solution in dioxane compare with thin film. The energy gap is slightly dependent on the thin film thickness. The optical constant of absorption coefficient α, refractive index, n, and extinction coefficient, k, were calculated and it was found that they are slightly dependent of film thickness.
Dispersion studies and electronic transitions in nickel phthalocyanine thin films
Optics and Laser Technology, 2005
Thin films of the organic semiconductor nickel phthalocyanine (NiPc) are structurally investigated using X-ray diffraction and infrared light absorption. The optical absorption and dispersion studies of nickel phthalocyanine were investigated using spectrophotometric measurements of transmittance and reflectance at normal incidence in the wavelength range 190-2100 nm. The absorption spectra recorded in the UV-VIS region show two well-defined absorption bands of the phthacyanine molecules, namely, the Soret and the Q-band. The Davydove splitting of the main absorption peak in the metal phthalocyanines correlates with the relative tendencies of the metal to out-of-plane bonding. The refractive index n as well as the absorption index k were calculated and showed an independent of the film thickness in the film thicknesses range 400-770 nm. The refractive index n showed an anomalous dispersion in the absorption region as well as normal dispersion in the transparent region. Some of the important optical absorption such as the molar extinction coefficient, the oscillator strength, the electric dipole strength have been evaluated. The analysis of the spectral behavior of the absorption coefficient a in the absorption region revealed two indirect allowed transitions with corresponding energies 2.7770.03 and 1.6670.02 eV. An energy band diagram has been proposed to account for the optical transitions of NiPc thin film. All previous parameters were as well obtained for films annealed at 523 K for 2 h. Discussion of the obtained results and their comparison with the previously published data are also given. r
Optical properties of metal phthalocyanines
Journal of Materials Science, 2010
In this study, optical properties of phthalocyanines of five metals, i.e., cobalt, nickel, iron, copper, and manganese, have been discussed in the energy (E) range of 1.5-4.1 eV. Utilizing the available data of refractive index (n) and extinction coefficient (k) of these materials in the literature, the related optical properties such as the real (e 1), imaginary (e 2) parts of the complex dielectric constant (e), and reflectivity (R) are calculated. Interpretations for the energies corresponding to the peaks in e 2 are explained in terms of the Penn gap (E P). High-frequency dielectric constant (e ?) values corresponding to four models, i.e., the conventional Lorentz model, modified Lorentz model, relaxed Lorentz model, and the dual Lorentz model are used to determine E P. It is found that the E P values corresponding to the conventional and dual Lorentz models are in good agreement with the average of energy peaks in the RE and the e 2-E spectra. The oscillator energy (E 0) and the dispersion energy (E d) of these materials have been determined utilizing the Wemple-DiDomenico model. The calculated values of (a) E 0 are generally in good agreement with the Penn gap E P , the average of the energy peaks in the RE and the e 2-E spectra and (b) E d are comparable to those in the literature for CoPc and NiPc.
Materials Science and Engineering: C, 2002
Chemical sensors based on surface plasmon resonance (SPR) measurements have been proposed in various applications ranging from biomedical and environmental monitoring to industrial process control. It is widely gaining recognition as a valuable tool to investigate gas sensing interactions. In this work, surface plasmon resonance studies in angular modulation have been used to characterise response in the presence of NO 2 toxic gas of thin TiO 2 porous films containing different types of metal-phthalocyanines. The hybrid thin films were prepared using sol -gel technique. Low temperature annealing of the films (80 jC) ensured the formation of microporous TiO 2 backbone and the preservation of phthalocyanine. Optical parameters of the active layers in dry air were calculated by using the SPR measurements and information about their variation in the presence of different concentrations of toxic gas was obtained. D
(2006) Ultraviolet and visible spectroscopic studies of phthalocyanine and its complexes thin films
Thin films of phthalocyanine and its complexes [magnesium, manganese, iron, cobalt, zinc and lead phthalocyanine] have been prepared by vacuum evaporation technique. The morphology of the deposited films has been studied using scanning electron microscope (SEM). The absorption, transmission and reflection spectra of these films have been studied in the wavelength range from 300 to 1000 nm. The optical band gap has been calculated from the absorption coefficient. It depending on the number of electron in the outer shell of the central metal. The extinction coefficient has been calculated directly from the spectra data. Also, the refractive indexes have been measured and discussed in the same range of wavelength from the absorption coefficient and extinction coefficient.
Phthalocyanines and phthalocyanine analogues: The quest for applicable optical properties
Monatshefte für Chemie …, 2001
The central subject of this article is the description of the current work of the authors in the context of the Cost Action 518, project DE-1, and the Phthalocyanines Research Training Network, both ®nanced by the European Community. The aim of the above projects is the design, synthesis, and structural and physical characterization of molecular and polymeric materials based on phthalocyanine derivatives with particular optical properties, as well as the study of their technological applications in the sensors ®eld.