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1
Content available remote

Optical Properties of Semiladder Polymer Foils

100%
Jarząbek B., Orlik T., Cisowski J., Schab-Balcerzak E., Sęk D.
Acta Physica Polonica A
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2000
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vol. 98
|
issue 5
655-659
EN
Optical transmission of amorphous polyimidazopyrrolone foils (pyrrons) were investigated in the spectral range 200-3300nm. The investigated materials exhibit a high transmission level (up to 85%) in a wide range from about 500 to 2750nm. The short wavelength edge of transmission depends on the pyrron chemical structure being different for ether-, amide- and ester bridges. When analysing the experimental data, we applied the approach used for amorphous materials in order to determine the electronic structure parameters which may be related to the influence of polyimidazopyrrolone bridge structure and structural disorder on the optical properties and probable electronic transitions.
2
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Electrical and Interfacial Properties of p-Si/P3HT Organic-on-Inorganic Junction Barrier

100%
Yakuphanoglu F., Shah M., Aslam Farooq W.
Acta Physica Polonica A
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2011
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vol. 120
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issue 3
558-562
EN
The electrical characterization of the Al/p-Si/P3HT/Ag organic-on-inorganic diode was done by current-voltage, capacitance-voltage and conductance-voltage methods. The values of ideality factor and barrier height of the diode were determined from the current-voltage characteristics and found as 2.32 and 0.77 eV, respectively. These values were also determined from Cheung's functions and Norde's method due to the non-ideal behavior of the diode. The electronic parameters obtained from the various methods indicate a good consistency with each other. The density of interface states for Al/p-Si/P3HT/Ag organic-on-inorganic diode was found to be 7.64 × 10^{10} cm^{-2} eV^{-1}. The obtained electrical parameters of the Al/p-Si/P3HT/Ag organic-on-inorganic diode are higher than that of the conventional Ag/p-Si Schottky diodes. This indicates that the electrical properties of the silicon Schottky diodes can be controlled using organic interfacial layer.
3
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Dielectric Permeability of Nanocylinder

100%
Jaćimovski S., Sajfert V., Raković D., Tošić B.
Acta Physica Polonica A
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2010
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vol. 117
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issue 5
738-744
EN
In the nanocylinder, a cut-off from the molecular crystal, dielectric permeability tensor is investigated. Excitons in the nanocylinder arise due to the exciting of the electron subsystem of the molecule. In evaluation of dielectric permeability Dzhyaloshinskii-Pitaevskii approach is used, connected with retarded and advanced exciton Green's functions and correct use of Paulion Green's function. It turned out that refraction and absorption indices depend on configuration coordinates, having maximal values at boundary cross-sections and minimal value at central cross-section of the nanocylinder broken symmetry structure. Although it was expected that boundary conditions make higher refractive and absorptive characteristics of the nanocylinder, this appeared not to be possible because Paulion Green's function is not proportional to the exciton concentration.
4
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Intermolecular Interactions in Organic Dye Monolayers Formed by Langmuir-Blodgett Technique

80%
Bauman D.
Acta Physica Polonica A
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2010
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vol. 117
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issue 4
525-531
EN
Langmuir and Langmuir-Blodgett films of some organic dyes (perylene-like dyes, derivatives of 4-amino-naphthali-mide, derivatives of naphthoylene-benzi-mida-zole, azo dyes) and their mixtures with thermotropic liquid crystal or arachidic acid have been investigated. Surface pressure as a function of the mean molecular area for the Langmuir films were measured and information about organization of molecules at the air-water interface has been obtained. Absorption spectra in situ for the Langmuir films and both absorption and fluorescence spectra for Langmuir-Blodgett films were recorded. The results obtained from spectroscopic studies have led to conclusions about formation of self-aggregates of dye molecules, both in ground and excited states, at the phases interfaces.
5
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Conduction Mechanism of 4-Aminoantipyrine as a New Organic Semiconductor

80%
Yahia I.
Acta Physica Polonica A
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2014
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vol. 125
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issue 5
1167-1171
EN
X-ray diffraction pattern of 4-aminoantipyrine was studied and it is a single phase with a polycrystalline structure. 4-aminoantipyrine has hexagonal structure with space group P6/mcc. The electrical properties of 4-aminoantipyrine were studied in the temperature range (303-373 K) below the melting point of the studied compound and in the frequency range (100 Hz-100 kHz). The obtained results of dc conductivity showed a positive temperature coefficient at the lower temperatures and a negative temperature coefficient at the higher temperatures. The ac conductivity obeys the power law. Ac conductivity can be reasonably interpreted in terms of overlapping-large polaron tunneling model and the correlated barrier hopping model. 4-aminoantipyrine is a good candidate for electronic device due to its electrical conductivity and capacitance.
6
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Studies of Optical Properties of Protonated Polyazomethine Thin Films

80%
Bednarski H., Weszka J., Domański M., Cozan V.
Acta Physica Polonica A
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2011
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vol. 120
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issue 5
939-941
EN
We report results of experimental studies supplemented with the first principles calculations aimed to explain influence of doping on electronic and optoelectronic properties of thin PPI films. It has been predicted theoretically and confirmed experimentally that chemical doping with the HCl acid vapor is thermally reversible process due to relatively low energy barrier for protonation.
7
Content available remote

Photo-Induced Structural Changes at a Surface οf Organic Single Crystals Observed by Vibrational Sum Frequency Generation Spectroscopy

80%
Fukumoto K., Fukazawa N., Ishikawa T., Koshihara S., Yamamoto H., Kato R., Onda K.
Acta Physica Polonica A
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2012
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vol. 121
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issue 2
313-315
EN
Phase transitions from insulator to metal induced by thermal excitation and by photo-irradiation at the surface of β'-(BEDT-TTF)(TCNQ) are investigated using vibrational sum frequency generation spectroscopy. The results are compared with linear reflectivity measurements which detect the information mainly from bulk. IR absorption spectra of a_{g} vibrational modes of TCNQ induced by the dimerization are observed using vibrational sum frequency generation spectroscopy, and its intensity is found to become smaller by thermal excitation indicating the transition to the metal phase. Time-dependent degree of dimerization is also observed by pump-probe experiments with almost the same statistics as the static measurements. On the other hand, in the reflectivity experiments, the reduction of dimerization is also observed by elevating the temperature, however, the spectral shapes are deformed for the time-resolved measurements. These results imply that the different dynamics occur at the surface and in the bulk.
8
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Modification of Optical and Electrical Properties of PET Foils by He⁺, Ne⁺ and Ar⁺ Implantation

80%
Droździel A., Turek M., Pyszniak K., Prucnal S., Luchowski R., Grudziński W., Klimek-Turek A., Partyka J.
Acta Physica Polonica A
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2017
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vol. 132
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issue 2
264-269
EN
Thin (3 μm) polyethylene terephthalate (PET) foils were irradiated with 135 keV He⁺, Ne⁺ and Ar⁺ ions with the fluences up to 5×10¹⁵ cm¯². Changes of chemical structure of the polymer were studied with the Fourier transform infrared and Raman spectroscopy - breaking of numerous chemical bonds, polymer chain cross-linking as well as formation of sp² hybridised carbon clusters and cluster networks were demonstrated. The increase of the implanted sample absorbance with the implantation fluence in the UV-VIS spectra as well as the decrease of optical band-gap energy (2.75 and 2.0 eV for He and Ne, respectively, at 5×10¹⁵ cm¯²) are observed. Decrease of bulk resistance of heavily treated samples by ≈5 orders of magnitude is determined. Measurements of the sheet resistance confirm that the sample becomes conducting also on the reverse (unimplanted) side of the foil. Both of these effects depend on the impinging ion mass - they are the strongest for Ar. The increase of both ac conductance and dielectric constant is observed in the frequency range up to 2 MHz and these changes rise with the impinging ion mass.
9
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Slow Dynamics of the Photoinduced Phase Transition in Pd(dmit)_2 Salts (dmit = 1,3-dithiol-2-thione-4,5-dithiolate)

70%
Ishikawa T., Tanaka T., Fukazawa N., Matsubara Y., Okimoto Y., Onda K., Koshihara S., Tamura M., Kato R.
Acta Physica Polonica A
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2012
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vol. 121
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issue 2B
316-318
EN
Slow dynamics of the initially photoinduced state has been observed by the pump-probe type time-resolved reflection spectroscopy in the charge separated phase of the half-filled strong dimer system, Et_2Me_2Sb[Pd(dmit)_2]_2 (dmit = 1,3-dithiol-2-thione-4,5-dithiolate). We have succeeded to reproduce the probe photon energy dependence of the time profile qualitatively in the time delay range from 10 ps to 1 ns assuming the dynamical expansion of the domain of the photo-induced dimer-Mott insulating phase in the host charge-separated one.
10
Content available remote

NIR photoresponse in the mixed phthalocyanine films

51%
Pakhomov G., Kuzin E., Murel A.
Open Physics
|
2006
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vol. 4
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issue 4
494-502
EN
The structure, optical and conducting properties of thin vacuum deposited films of erbium bisphthalocyanine (Pc2Er) and its mixtures with metal-free phthalocyanine (H2Pc) have been studied with particular reference to the near infrared (NIR). It has been found that, in spite of intense optical absorbance over the UV/Vis/NIR domain, pure Pc2Er films are weakly photoconductive. However, in the mixed Pc2Er/H2Pc films the photocurrent signal was detected in the NIR range of 1200–1500 nm, which is associated with optical activity of Pc2Er molecules.
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