Browsing by Author "Borczyskowski, C. von"

Now showing items 1-20 of 24

    • Ab initio Study of Exciton Transfer Dynamics from a Core-Shell Semiconductor Quantum-Dot to a Porphyrin-Sensitizer 

      Kilin, D. S.; Tsemekhman, K.; Prezhdo, O. V.; Zenkevich, E. I.; Borczyskowski, C. von (2007)
      The observed resonance energy transfer in nanoassemblies of CdSe/ZnS quantum dots and pyridyl-substituted free-base porphyrin molecules [Zenkevich et al., J. Phys. Chem. B 109 (2005) 8679] is studied computationally by ab initio electronic structure and quantum dynamics approaches. The system harvests light in a broad energy range and can transfer the excitation from the dot ...
      2017-05-27

    • Assembly principles and relaxation processes in nanosized heterogeneous complexes: Multiporphyrin structures and CdSе/ZnS nanocrystals 

      Zenkevich, E. I.; Borczyskowski, C. von (2009)
      Based on the extra-ligand addition effect, the principles of targeted self-assembly of nanosized multiporphyrin complexes of various types with controllable geometry and composition (up to 8 tetrapyrroles) and heterogeneous composites based on trioctylphosphine oxide-stabilized CdSe/ZnS semiconductor nanocrystals and organic compounds were developed. The dynamics and mechanisms ...
      2017-05-27

    • Competition between electron transfer and energy migration in self-assembled porphyrin triads 

      Zenkevich, E. I.; Willert, A.; Bachilo, S. M.; Rempel, U.; Kilin, D. S.; Shulga, A. M.; Borczyskowski, C. von (2001)
      The photoinduced electron transfer (ET) and the energy migration (EM) processes have been studied in liquid solutions and polymeric (PMMA) films for the triads consisting of the Zn-octaethylporphyrin chemical dimer (the energy and electron donor, D) and dipyridyl substituted tetrapyrrole extra-ligands (porphyrins, chlorin, tetrahydroporphyrin) as the acceptors, A. On the basis ...
      2017-05-26

    • Complexation and interchromophoric interactions in self-organized porphyrin and chlorin triads 

      Chernook, A. V.; Shulga, A. M.; Zenkevich, E. I.; Rempel, U.; Borczyskowski, C. von (1996)
      Spectral properties and equilibrium constants of multimolecular complexes (triads) formed by 2-fold coordination of dipyridyl-substituted free bases of porphyrin, chlorin, or tetrahydroporphyrin with Zn-porphyrin and Zn-chlorin dimers bridged by either of two different spacers between the monomeric entities have been studied in methylcyclohexane at room temperature. The ability ...
      2017-05-18

    • Dynamics of photoinduced electron transfer in multiporphyrin nanoassemblies 

      Kilin, D.; Zenkevich, E.; Borczyskowski, C. von (World Scientific Publishing Co., 2015)
      In self-assembled nanoscale porphyrin triads based on Zn-octaethylporphyrin chemical dimer (donor, D) and dipyridyl substituted porphyrin free base (acceptor, A), fluorescence quenching of D (down to 1.7-10 ps) and A (by ~1.3-1.6 times) subunits is strongly dependent on the solvent polarity (toluene-acetone mixtures) and temperature (77-350 K). The obtained experimental findings ...
      2017-05-27

    • Electron transfer in porphyrin multimolecular self-organized nanostructures 

      Zenkevich, E. I.; Bachilo, S. M.; Shulga, A. M.; Rempel, U.; Willert, A.; Borczyskowski, C. von (1998)
      On the base of of covalent and non-covalent bonds nanoscale self-assembling multiporphyrin arrays with well-defined geometry, the controllable number of interacting components and their spectral and photophysical properties were formed. The deactivation of excited singlet and triplet states was studied using steady-state, time-resolved picosecond fluorescence (∆½≈30 ps) and ...
      2017-05-25

    • Formation and optical properties of self-organized pentameric porphyrin arrays 

      Chernook, A. V.; Rempel, U.; Borczyskowski, C. von; Zenkevich, E. I.; Shulga, A. (1996)
      Principles of formation, electronic absorption and fluorescence spectra are reported for self-organized pentameric arrays of tetrapyrrolic macrocycles. In these arrays two molecules of Zn-porphyrin dimers, Zn(II)l,4-bis[5-(10,15,20-tri-p-hexylphenylporphyrinyl)]-benzene ((ZnHTPP)₂) are bound via one molecule of a tetrapyridyl-substituted free base of porphyrin or tetrahydroporphyrin. ...
      2017-05-25

    • Formation Principles and Ligand Dynamics for Nanoassemblies of CdSe Quantum Dots and Functionalized Dye Molecules 

      Blaudeck, T.; Zenkevich, E.; Abdel-Mottaleb, M.; Szwaykowska, K.; Kowerko, D.; Cichos, F.; Borczyskowski, C. von (2012)
      Functional dye molecules, such as porphyrins, attached to CdSe quantum dots (QDs) through anchoring meso-pyridyl substituents, form quasi-stable nanoassemblies. This fact results in photoluminescence (PL) quenching of the QDs both due to Förster resonance energy transfer (FRET) and the formation of non-radiative surface states under conditions of quantum confinement (non-FRET). ...
      2017-05-27

    • Identification and assignment of porphyrin-CdSe Hetero-nanoassemblies 

      Zenkevich, E. I.; Blaudeck, T.; Shulga, A. M.; Cichos, F.; Borczyskowski, C. von (2007)
      Hetero-nanoassemblies in toluene solution are formed via anchoring pyridyl substituted free base porphyrin molecules on the colloidal core-shell semiconductor nanocrystals CdSe/ZnS. The formation can be identified via quenching of semiconductor photoluminescence and followed via spectral changes of porphyrin spectral properties such as fluorescence, fluorescence decay and absorption. ...
      2017-05-27

    • Influence of Single Dye Molecules on Temperature and Time Dependent Optical Properties of CdSe/ZnS Quantum Dots: Ensemble and Single Nanoassembly Detection 

      Zenkevich, E. I.; Stupak, A. P.; Kowerko, D.; Borczyskowski, C. von (2012)
      Optical spectroscopy on ensembles and single CdSe/ZnS semiconductor quantum dots (QDs) demonstrates a competition of trap and near band edge photoluminescence (PL). This competition can be markedly influenced by a few surface attached pyridyl functionalized dye molecules (porphyrins or perylene diimides) forming nanoassemblies with well defined geometries. Temperature variation ...
      2017-05-27

    • Interaction of multiporphyrin systems with molecular oxygen in liquid solutions: Extra-ligation and screening effects 

      Sagun, E. I.; Zenkevich, E. I.; Knyukshto, V. N.; Shulga, A. M.; Starukhin, D. A.; Borczyskowski, C. von (2002)
      Steady-state and time-resolved studies indicate that for a sequence of porphyrin or chlorin chemical dimers Zn-cyclodimer → (ZnOEP)₂Ph → (ZnOEP)₂ → (ZnHTPP)₂ → (ZnOEChl)₂ with relative lowering of excited S₁- and T₁-states, the extra-ligation by pyridine (PYR) does not influence essentially on fluorescence parameters but leads to an increase of T₁-states non-radiative decay (the ...
      2017-05-26

    • Laser confocal and spatially-resolved fluorescence spectroscopy of porphyrin distribution on plasma deposited polymer films 

      Zenkevich, E. I.; Martin, J.; Borczyskowski, C. von; Ageeva, T. A.; Titov, V. A.; Knyukshto, V. N. (2008)
      Laser confocal microscopy and spatially-resolved fluorescence spectroscopy have been used for the study of the interaction of di(p-aminophenyl)etioporphyrin (DAPEP) and tetra(p-aminophenyl)porphyrin (TAPP) molecules with the surface of thin (7-15 μm) polypropylene films treated by 0.5 M KCl solution and activated by air non-equilibrium plasma at the normal atmospheric pressure. ...
      2017-05-27

    • Ligand dynamics and temperature effects upon formation of nanocomposites based on semiconductor CdSе/ZnS quantum dots and porphyrins: ensemble and single object measurements 

      Zenkevich, E. I.; Blaudeck, T.; Kowerko, D.; Stupak, A. P.; Cichos, F.; Borczyskowski, C. von (2012)
      Dye molecules with pyridyl side substituents (porphyrins and heterocyclic perylene diimides) coordinatively attached to semiconductor CdSe/ZnS quantum dots (QDs) surface form quasi-stable “QD-Dye” nanocomposites of various geometry in the competition with capping molecules (tri-n-octyl phosphine oxide or long chain amines) exchange. This results in photoluminescence (PL) quenching ...
      2017-05-27

    • Multistep photoinduced electron transfer in self-organised nano-scale porphyrin triads 

      Zenkevich, E. I.; Shulga, A. M.; Borczyskowski, C. von (2002)
      Well-defined structurally organised porphyrin triads of a controlled geometry andnanoscale size have been formed in liquid solutions using the combination of a covalent approach and non-covalent self-assembly. The triads contain zinc-octaethylporphyrin chemical dimer, (ZnOEP)₂Ph, with covalently linked electron acceptors (p-benzoquinone, Q or pyromellitimide, Pim), and additional ...
      2017-05-26

    • Photoinduced charge transfer via "Superexchange" mechanism in porphyrin triads with electron acceptors 

      Zenkevich, E. I.; Willert, A.; Borczyskowski, C. von (РИВШ, 2017)
      Zenkevich, E. I. Photoinduced charge transfer via "Superexchange" mechanism in porphyrin triads with electron acceptors / E. I. Zenkevich, A. Willert, C. von Borczyskowski // Квантовая электроника : материалы XI Международной научно-технической конференции, Минск, 13—17 ноября 2017 года / [редкол.: М. М. Кугейко (ответственный редактор) и др.]. – Минск : РИВШ, 2017. – С. 35-36.
      2021-06-28

    • Photoinduced electron transfer dynamics for self-assembled porphyrin arrays in solutions and films 

      Zenkevich, E. I.; Kilin, D. S.; Willert, A.; Bachilo, S. M.; Shulga, A. M.; Rempel, U.; Borczyskowski, C. von (2001)
      Electronic excitation energy deactivation in self-assembled porphyrin triads has been studied by the time correlated single photon counting technique as a function of the solvent polarity (toluene-acetone mixtures), temperature (77-350 K), and mutual spatial arrangement of the donor and acceptor subunits. The donor (Zn-octaethylporphyrin chemical dimer) fluorescence quenching ...
      2017-05-26

    • Photoinduced relaxation processes in self-assembled nanostructures: multiporphyrin complexes and composites "CdSе/ZnS quantum dot-porphyrin" 

      Zenkevich, E. I.; Borczyskowski, C. von (2009)
      Here, we discuss self-assembled multicomponent organic/inorganic nanostructures. Self-assembled multiporphyrin triads were formed via non-covalent interactions of meso-phenyl bridged ZnOEP chemical dimer, (ZnOEP)₂Ph, with dipyridyl substituted tetrapyrrole extra-ligand. In tetrads, the dimer (ZnOEP)₂Ph is covalently linked via 5-mesoposition to additional electron acceptors ...
      2017-05-27

    • Photonics and relaxation pathways for self-assembled nanostructures: multiporphyrin complexes and nanocomposites «semiconductor CdSe/ZnS quantum dot - organic dye» 

      Zenkevich, E.; Borczyskowski, C. von (BNTU, 2013)
      Zenkevich, E. Photonics and relaxation pathways for self-assembled nanostructures: multiporphyrin complexes and nanocomposites «semiconductor CdSe/ZnS quantum dot - organic dye» / E. Zenkevich, C. von Borczyskowski // Фотоника: наука в производство = Photonics: science into production : сборник материалов белорусско-китайского форума, 12-13 декабря 2013 г. – Minsk : BNTU, 2013. ...
      2018-05-28

    • Self-assembled nanoscale photomimetic models: structure and related dynamics 

      Zenkevich, E. I.; Borczyskowski, C. von; Shulga, A. M.; Bachilo, S. M.; Rempel, U.; Willert, A. (2002)
      Using static and time-resolved measurements, dynamics of non-radiative relaxation processes have been studied in self-assembled porphyrin triads of various geometry, containing the main biomimetic components, Zn–porphyrin dimers, free-base extra-ligands (porphyrin, chlorin or tetrahydroporphyrin), and electron acceptors A (quinone or pyromellitimide). The strong quenching of the ...
      2017-05-26

    • Self-organization principles in the formation of multiporphyrin complexes and “semiconductor quantum dot-porphyrin” nanoassemblies 

      Zenkevich, E. I.; Borczyskowski, C. von (2014)
      In this paper, we review several aspects of molecular recognition (based on non-covalent binding interactions) occurring between meso-pyridyl substituted tetrapyrrole extra-ligands and chemical dimers of tetrapyrrolic macrocycles containing central Zn ions and spacers of various nature and flexibility. Experimental results obtained by us earlier are analyzed using a novel approach ...
      2017-05-27