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

Przeglądaj

Wyniki wyszukiwania

Teraz wyświetlane 1 - 10 z 25

Volume conductivity of polycrystalline tetracene and p-quaterphenyl layers modified under influence of the surface adsorption
(Wydawnictwo Politechniki Łódzkiej, 2021) Kania, Sylwester; Kuliński, Janusz; Kościelniak-Mucha, Barbara; Słoma, Piotr; Wojciechowski, Krzysztof
Volume conductivity of thin organic layers in contact with the ambient atmosphere depends on the volume properties and on the adsorption processes on the free surface of the layer. In order to clarify the role of the surface, experiments were carried out at a temperature close to 293 K to determine the influence of the adsorption dynamics on the change of characteristic relationships observed for the transport of electric charge in vacuum, in the ambient atmosphere and in the controlled atmosphere of the ethyl alcohol vapors. The investigations were carried out for two linear tetracyclic molecular structures, i.e. p-tetraphenyl and tetracene. These molecular systems differ in organization of the rings. The results show an increase in conductivity measured for both compounds when there are the molecules capable of adsorbing to the surface and to transfer or receive charge carriers connected with the process of diffusion or drift transport in the volume of the layer. The nature of the observed increase in conductivity proves that the hopping mechanism is present in the case of conductivity of both tested materials.
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.
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.
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.
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.
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.
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
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.
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.
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.

Scientific Bulletin. Physics.

Przeglądaj

Filtry

Ustawienia

Sortuj według

Wyników na stronie

Wyniki wyszukiwania