Scientific Bulletin. Physics.

Stały URI zbioruhttp://hdl.handle.net/11652/2752

W czasopiśmie Scientific Bulletin. Physics publikowane są artykuły pracowników i studentów Instytutu Fizyki PŁ, pracowników Centrum Nauczania Matematyki i Fizyki PŁ oraz pracowników innych uczelni, dotyczące najnowszych badań we wszystkich dziedzinach fizyki. Ukazuje się jeden zeszyt rocznie. Czasopismo wydawane jest w języku angielskim. Wszystkie prace są recenzowane. Czasopismo jest indeksowane w bazie BazTech.

The Scientific Bulletin. Physics journal publishes articles of employees and students of the Institute of Physics, Technical University of Lodz, employees of the Center for Teaching Mathematics and Physics, and employees of other universities, regarding the latest research in all areas of physics. One issue is published every year. The journal is published in English. All works are reviewed. The journal is indexed in the BazTech database.

Strona wydawcy : https://wydawnictwo.p.lodz.pl

Strona czasopisma : https://eczasopisma.p.lodz.pl/PHYSICS

DOI : 10.34658/physics

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Ab initio investigation of ethanol-tetracene interactions during adsorption
(Wydawnictwo Politechniki Łódzkiej, 2018) Kania, Sylwester; Kościelniak-Mucha, Barbara; Słoma, Piotr; Wojciechowski, Krzysztof
Ab initio calculations presented in this work are performed to investigate the geometry, interaction energy and bonding properties of binary complexes formed between neutral ethanol and tetracene molecules. Two different geometries were applied for the study. The interaction energies between molecules in the complex posses minimum at the distance of about 3.6 A among oxygen atom in ethanol and the neighbouring carbon atom of tetracene skeleton.
Charge carrier mobility in non-equilibrated transport in molecular materials
(Lodz University of Technology Press, 2019) Kania, Sylwester; Kościelniak-Mucha, Barbara; Kuliński, Janusz; Słoma, Piotr; Wojciechowski, Krzysztof
Non-equilibrated transport of charge carriers in the molecular material depends on the structure and packing of the molecules. Explanation of the measurements of the photocurrent generated with use of UV flash light in organic layer needs to define the quantity of charge carriers mobility. Definition of this quantity in the scope of some defined transport model requires the detailed analysis of generation, recombination and charge transfer between neighbouring molecules. The problem is discuss on the basis of transport properties of two anthracene derivatives
Comparative study of the influence of the reorganization energy on the hole transport of two four-cyclic arenes
(Wydawnictwo Politechniki Łódzkiej, 2017) Kania, Sylwester; Kuliński, Janusz; Sikorski, Dominik
Application of the method of quantum-mechanical calculations allowed the determination of the reorganization energy of the molecules of tetracene and p-quaterphenyl and the estimation of the transfer rate integral between neighbouring molecules present in the solid state. Comparison of the transfer rates for holes with the values of the mobility, obtained experimentally for the polycrystalline tetracene layers and p-quaterphenyl layers vaporized in the vacuum in the similar conditions indicate that the molecule’s structure possess the dominate impact on the conductivity of the thin layers of these compounds.
Comparison of methods for simulation of the optical properties of VCSELs
(Wydawnictwo Politechniki Łódzkiej, 2017) Więckowska, Marta; Dems, Maciej; Czyszanowski, Tomasz
This paper presents the differences arising from the use of scalar (Effective Frequency Method) and vector (Fourier’s and Bessel’s Admittance Methods) calculation methods in optical analysis of arsenide Vertical-Cavity Surface-Emitting Lasers (VCSELs). Discussed results demonstrate that the vector methods are more accurate than the scalar one, but also they are more time consuming. By comparing two vector methods, it can be seen that the Bessel’s Admittance Method allows to obtain similar qualitatively and quantitatively results in a slightly shorter time. The calculations were performed for structures with varied aperture radius and its location in the resonant cavity. Moreover, this paper includes the comparison of calculation results for a structure in which there are layers with gradually changing refractive index, and the structure in which these layers are replaced by a layer with a constant average refractive index.
Comparison of some properties and molecular structure of MHPOBC and chlorinated MHPOBC
(Wydawnictwo Politechniki Łódzkiej, 2020) Bąk, Grzegorz W.
Comparison of molecular structure of MHPOBC and chlorinated MHPOBC has been made and presented in the paper. The main difference in molecular structure of MHPOBC and chlorinated MHPOBC molecules consists in different properties of two chemical bonds between the benzene ring with substituted chlorine atom and neighbouring parts of molecule. For chlorinated version of MHPOBC the component of molecular dipole moment perpendicular to the long axis of molecule is substantially smaller than for MHPOBC molecules. As a result of chlorination core of MHPOBC molecules becomes more flexible. These differences of molecular structure lead to easily noticeable differences in macroscopic properties of MHPOBC and its chlorinated version.
Current dependence of resistances and capacitances in a vertical-cavity surface-emitting laser
(Wydawnictwo Politechniki Łódzkiej, 2017) Komar, Paulina; Śpiewak, Patrycja; Gębski, Marcin; Lott, James A.; Wasiak, Michał
Based on the model of impedance and modulation time constants for vertical-cavity surface-emitting lasers (VCSELs) we study the resistances and capacitances of an equivalent circuit as a function of the current flowing through the VCSEL. We observe reduction of some components of the resistance and the capacitance, as well as the modulation time constants for increasing current.
A DFT study of reorganization energy of some chosen carbazole derivatives
(Wydawnictwo Politechniki Łódzkiej, 2020) Kania, Sylwester; Kościelniak-Mucha, Barbara; Kuliński, Janusz; Słoma, Piotr; Wojciechowski, Krzysztof
Strong efforts toward finding an organic semiconductor with a molecule characterized by a low charge transfer energy applying quantum-chemical calculations are undertaken. Density Functional Theory (DFT) calculations made for carbazole (Cz) and three isomers of benzocarbazole, benzo (a) carbazole (BaCz), benzo (b) carbazole (BbCz) and benzo (c) carbazole (BcCz) proves the possibility of lacking the growth of reorganization energy despite the molecule dimentions enlargement. Benzo(b)carbazole molecules with high longitudinal dimension of the rigid skeleton d = 9,05 Å posses the low value of reorganization energy for both hole and electron transport of 0,18 eV and 0,11 eV, respectively. We suggest that the reduction of reorganization energy may be related to the diminishing of intramolecular hydrogen interactions.
The effect of the dipole moment on hole conductivity of polycrystalline films of two anthracene derivatives
(Wydawnictwo Politechniki Łódzkiej, 2017) Kania, Sylwester; Kościelniak-Mucha, Barbara; Kuliński, Janusz; Słoma, Piotr; Wojciechowski, Krzysztof
Hole mobility in the polycrystalline layers of anthrone and anthraquinone differs in one order of magnitude in spite of nearly the same crystalline structure. The origin of this difference was determined with use of the quantum-mechanical calculations carried out at the density functional theory level using the B3lYP functional in conjunction with the 6-311++G(d,p) basis set. Based on theses calculations, we suppose that these difference can result from the presence of the dipol moment in the anthrone molecules.
Electrical and thermal properties of anthraquinone layers
(Lodz University of Technology Press, 2019) Kania, Sylwester; Kuliński, Janusz; Sikorski, Dominik
Quantum-chemical calculations indicate that the bond lengths in the anthraquinone anthracene backbone are shorter than the corresponding bonds in unsubstituted anthracene. The shape of the frontier molecular orbitals (FMO) indicates the possibility of more efficient electron capture by the anthraquinone molecule than by the anthracene molecule while maintaining stability in the conditions prevailing in electrochemical cells. Differential scanning calorimetry (DSC) studies indicate the temperature stability of anthraquinone above the melting point up to 300C. The glass transition is determined at about 100°C.
Electrical and thermal properties of anthrone
(Wydawnictwo Politechniki Łódzkiej, 2020) Kania, Sylwester; Kuliński, Janusz; Sikorski, Dominik
Quantum-chemical density functional theorem (DFT) calculations indicate that the value of the reorganization energy indicates the possibility of efficient hole capture by the anthrone molecule during transport process of charge carriers. Differential scanning calorimetry (DSC) studies indicate the temperature stability of anthrone molecules above the melting point up to 164°C. The glass transition is determined at 153.7 °C and melting point at 157.05 °C.
Flexoelectric torque in uniformly lying helix structures of chiral nematic liquid crystal
(Wydawnictwo Politechniki Łódzkiej, 2018) Buczkowska, Mariola
Electric field induced deformations of chiral nematic liquid crystal layers were studied numerically. Uniformly lying helix structure of short pitch flexoelectric mixtures was considered. The electro-optic effect due to rotation of optical axis around the normal to the layer was simulated. The flexoelectric torque arising under the action of bias voltage and responsible for this rotation was calculated. It was found that the prevailing torque occurs in close vicinity of the boundary plates. Nonlinearity of superposition of splay and bend contributions to the total flexoelectric torque was found.
Flexoelectro-optic effect with large rotation angle of optic axis
(Wydawnictwo Politechniki Łódzkiej, 2020) Buczkowska, Mariola
The flexoelectro-optic effect in layers of chiral nematics was investigated numerically. The simulations concerned short pitch materials with the helix axis parallel to the layer plane. Configurations which allow to avoid accumulation of ions at the electrodes and are suitable for square-wave driving voltage were considered. They were related to large rotation angles of the optical axis of the layer about the normal to the layer. Influence of chosen parameters on efficiency of the electro-optic effect was studied.
Frequency dependence of the Kerr constant in nynas nytro 3000 oil determined by the polarimetric method
(Wydawnictwo Politechniki Łódzkiej, 2018) Poborska, Julita; Dąbrówka, Dominika; Chwirot, Maksymilian; Ledzion, Rafał; Izdebski, Marek; Kucharczyk, Włodzimierz
Frequency dependence of the Kerr constant in nynas nytro 3000 oil determined by the polarimetric method A frequency dependence of the Kerr constant K in transformer oil Nynas Nytro 3000 within a frequency range 117-5017 Hz is determined. An averaged value (2.30 ± 0.03)·10ˉ¹⁵ m/V² for K is obtained. The constant is found to be weakly frequency dependent and approaches its maximum 2.37·10ˉ¹⁵ m/V² at about 3000 Hz. The Kerr constant is of comparable value to that observed in other mineral oils employed previously in measurements of the quadratic electro-optic effect and the electrostriction in crystals.
Influence of chirality on two-dimensional deformations of twisted flexoelectric nematic layers
(Lodz University of Technology Press, 2019) Buczkowska, Mariola
Two-dimensional deformations induced by electric field in twisted nematic cells filled with liquid crystal possessing flexoelectric properties were simulated numerically. The influence of chiral dopants on the occurrence and structure of the spatially periodic patterns was investigated. It was found that the chirality influences mainly the direction of the periodic patterns whereas the threshold voltage for deformation and the width of the stripes are weakly affected.
Influence of tilted surface alignment on flexoelectric domains in twisted nematic layers
(Wydawnictwo Politechniki Łódzkiej, 2017) Buczkowska, Mariola; Derfel, Grzegorz
The small deformations induced by electric field in twisted flexoelectric nematic layers were simulated numerically. The onedimensional (i.e. homogeneous over the whole area of the layer) and two-dimensional (i.e. spatially periodic flexoelectric domains) deformations were considered. It was shown that the periodic deformations do not arise if sufficiently high pretilt angle is imposed by the boundary conditions. The value of pretilt angle necessary for elimination of domains increases with the flexoelectric coefficient e33. This result is of practical meaning because the flexoelectric domains are undesirable from an applicative point of view since they destroy the homogeneous appearance of the area of an excited pixel of a display.
Intermolecular interactions for two chosen anthracene derivatives
(Wydawnictwo Politechniki Łódzkiej, 2021) Kania, Sylwester; Kuliński, Janusz; Kościelniak-Mucha, Barbara; Słoma, Piotr; Wojciechowski, Krzysztof
The nature of intermolecular interactions for anthrone and anthraquinone differs due to the symmetry of substitution of the central benzene ring, i.e. anthrone substituted with only one keto group and anthraquinone substituted with two keto groups. In order to interpret the interactions among the molecules, the interaction energies between molecules in crystals were calculated using DFT B3LYP calculations. The results reveal the consistency between calculated “lattice energies” and theirs terms and thermodynamical properties as density, boiling point and melting point of examined compounds.
The origin of the interaction responsible for the difference of hole mobility of thwo derivatives of anthracene
(Wydawnictwo Politechniki Łódzkiej, 2018) Kania, Sylwester; Kuliński, Janusz; Sikorski, Dominik
Hole mobility of the layers built from two anthracene derivatives differing in the substitution of the central benzene ring, i.e. anthrone substituted with only one keto group and anthraquinone substituted with two keto groups differs by one order of magnitude despite the fact that both have almost identical crystal structure. We ascribe this difference to existence of an additional intermolecular interaction arising in the layer of anthrone.
Polarization of organic aromatic molecule in anionic and cationic state
(Lodz University of Technology Press, 2019) Kania, Sylwester; Kościelniak-Mucha, Barbara; Kuliński, Janusz; Słoma, Piotr; Wojciechowski, Krzysztof
The modification of electron states and the change in the geometry of the structure of molecule during hopping transport of charge carriers depends on the symmetry of the molecule. During electric transport the molecule reversibly transforms from neutral state to cation when hole conductivity occurs or to anion when electron conductivity occurs. The energies of orbitals HOMO and HOMO1 of anthrone and anthrachinone are always negative, what allows for holes transport. Positive energies of LUMO and LUMO+1 orbitals of anion of anthrone and anthraquinone in structure of anion or neutral molecule make electron transport difficult.
Scientific Bulletin. Physics No. 1219, vol. 38 (2017)
(Lodz University of Technology Press, 2017) Lodz University of Technology; Politechnika Łódzka
Scientific Bulletin. Physics No. 1224, vol. 39 (2018)
(Lodz University of Technology Press, 2018) Lodz University of Technology; Politechnika Łódzka