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Absorption enhanced currents in thin layers of low dimension organics
(Wydawnictwo Politechniki Łódzkiej, 2011) Kania, Sylwester; Kuliński, Janusz
Transport processes enhanced by absorption of the volatile ethanol on the tetracene and p-quaterphenyl films are considered. Obtained results may approve chemisorption's mechanism with hydrogen bonding.
Activation processes for two chosen aromatic hydrocarbon materials
(Wydawnictwo Politechniki Łódzkiej, 2009) Kania, Sylwester; Kuliński, Janusz
The activation process and the transport process for electrons in the tetracene layers and holes in the p-quaterphenyl layers is considered. Obtained results may suggests the hopping transport through the localized states near the Fermi level as a dominant kind of transport. Observed dependence of the conductivity on the vapor concentration of the activator molecules may suggest that tetracene is better for utilization as a vapour sensors.
Adsorption induced hole transport in thin layers of non-ordered tetracene.
(Wydawnictwo Politechniki Łódzkiej, 2015) Kania, Sylwester; Kuliński, Janusz
Additional disorder induced by adsorption processes by the molecule of ambient are responsible for deep modulation of conductivity. Observations confirmed the dominated role of the increase of the free carrier concentration due to the increse the shallow trap concentration, for modulation of the conductivity.
Adsorption of ethanol to thin layer of acenes as a process of interconnected networks
(Wydawnictwo Politechniki Łódzkiej, 2013) Kania, Sylwester; Kuliński, Janusz
The activation process and the transport process for electrons in the tetracene layers and holes in the p-quaterphenyl layers is considered. Observed dependence of the conductivity on the vapor concentration of the activator molecules may suggests influence of collisions as a source of injection of charge through the surface potential barrier of adsorption. Applied model of two-body interactions in the interface of adsorption is approved on the basis of theory of area law for entanglement from exponential decay of correlations. Quantum description of adsorption of small hydrocarbon to the solid acenes involve only diagonal elements of the interaction matrix.
Bipolar transport of charge carriers in thin films of 9,10-dimethylanthracene and 1-acenaphthenol.
(Wydawnictwo Politechniki Łódzkiej, 2014) Kania, Sylwester; Kuliński, Janusz; Marciniak, Bernard; Różycka-Sokołowska, Ewa
The current-voltage (I-U) characteristics we have been measured for thin films of 1-acenaphthenol and 9,10-dimethylanthracene prepared from their commercially available materials as products with purity ≥ 10-3mass %. Using the method of differential processing of the characteristics, charge transport mechanism in these films was assessed.
Bipolar transport of charge carriers in thin films of 9,10-dimethylanthracene and 1-acenaphthenol.
(Lodz University of Technology Press, 2014) Kania, Sylwester; Kuliński, Janusz; Marciniak, Bernard; Różycka-Sokołowska, Ewa
The current-voltage (I-U) characteristics we have been measured for thin films of 1-acenaphthenol and 9,10-dimethylanthracene prepared from their commercially available materials as products with purity >_ 10-3 mass %. Using the method of differential processing of the characteristics, charge transport mechanism in these films was assessed.
Charge carrier conductivity mechanism for activated tetracene layers
(Wydawnictwo Politechniki Łódzkiej, 2008) Kania, Sylwester; Kuliński, Janusz
The activation process and the transport process for electrons in the tetracene layers is considered. Obtained results may suggests the hopping transport through the localized states near the Fermi level as a dominant kind of transport. Observed dependence of the conductivity on the vapor concentration of the activator molecules may suggest some ability to utilize.
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.
Conductivity due to active collisions channel of adsorption of ethanol to thin layer of acenes
(Wydawnictwo Politechniki Łódzkiej, 2012) Kania, Sylwester; Kuliński, Janusz
The activation process and the transport process for electrons in the tetracene layers and holes in the p-quaterphenyl layers is considered. Observed dependence of the conductivity on the vapor concentration of the activator molecules may suggests influence of collisions as a source of injection of the charge through surface potential barrier of adsorption.
Correlated networks in the adsorption enhanced currents.
(Wydawnictwo Politechniki Łódzkiej, 2014) Kania, Sylwester; Kuliński, Janusz
Injection of carriers into thin layers of acenes due to adsorption of ethanol activator molecules is considered as a electron transfer reaction between two phases. Complexity of the processes may be diminished with applying electron transfer theory in the meaning of Marcus.
Correlated networks in the adsorptionenhanced currents
(Lodz University of Technology Press, 2014) Kania, Sylwester; Kuliński, Janusz
Injection of carriers into thin layers of acenes due to adsorption of ethanol activator molecules is considered as a electron transfer reaction between two phases. Complexity of the processes may be diminished with applying electron transfer theory in the meaning of Marcus.
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 symmetry of a molecule electronic density on the dipole moment of unit cell and hole conductivity of thin polycrystalline films of anthrone and anthraquinone.
(Wydawnictwo Politechniki Łódzkiej, 2016) Kania, Sylwester; Kościelniak-Mucha, Barbara; Kuliński, Janusz; Słoma, Piotr; Wojciechowski, Krzysztof
The electronic structure of anthrone and anthraquinone molecules in the gas state and in the simulated crystal unit cell were calculated with time dependent-density functional theory (TD-DFT) method. The values of dipole moment of single molecule and of single crystal unit cell were also determined with TD-DFT method. The results of TD-DFT were compared with known crystal structures of both compounds [1,2]. For both molecules it was observed improvement of matching the length of corresponding bonds when calculated for the unit cell. Unexpectedly high value of dipole moment was calculated for the single unit cell of anthrone. This fact can be responsible for the nano-dimension properties of anthrone as the carriers mobility or high boiling point.
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.
Elimination of the impact of rc constant on transient photocurrents measured in organic layers.
(Wydawnictwo Politechniki Łódzkiej, 2016) Kania, Sylwester; Kuliński, Janusz
We present a calculation method for elimination of the effect of the RC constant of the measuring circuit in the time-of-flight (TOF) measurements where a pulse generation of the photocurrent in a thin layer of low-molecular organic material is exploited. Presented method allows to eliminate the influence of the component of displacement current related to dielectric losses and obtaining the actual conduction current time dependence. The method was tested on the thin layers of 1,5-dihydroxynaphthalene.
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.