Combined experimental and theoretical DFT study of molecular nanowires negative differential resistance and interaction with gold clusters

Záliš, Stanislav; Kratochvílová, Irena; Zambova, Adriana; Mbindyo, Jeremiah K. N.; Mallouk, Thomas E.; Mayer, Theresa S.

doi:10.1140/epje/i2005-10043-5

Cited by 22 publications

(13 citation statements)

References 28 publications

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“…[21][22][23] All quantum chemical calculations were done by means of the Gaussian 09 program 24 with standard settings. This method usually provides reliable ground-state conformations and other basic properties of π-conjugated molecules including their ions.…”

Section: Calculationsmentioning

confidence: 99%

Diketopyrrolopyrroles disubstituted with alkylated thiophenes: effect of the donor unit size and solubilizing substituents on their redox, photo- and electroluminescence properties

et al. 2015

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Systematic studies of redox, spectroscopic and electroluminescent properties of donor-acceptordonor (DAD) electroactive compounds consisting of diketopyrrolopyrrole central accepting unit symmetrically disubstituted with mono-, bi-or terthiophene (T1, T2 and T3 series) are presented. The potential of the diketopyrrolopyrrole unit reduction is influenced neither by the type of alkyl substituents at pyrrole nitrogen atoms, nor the position of alkyl substituents in thiophene rings of the D segment. Being in the range of -1.66 --1.67 V vs Fc/Fc + in the compounds of T1 series it is, however, raised by 100 -120 mV for the T3 series compounds.The oxidation potential of the studied compounds is even more strongly affected by D segment decreasing from 0.51 -0.52 V in T1 compounds to 0.25 -0.26 V vs Fc/Fc + in T3 ones. It is also dependent on the position of the alkyl solubilizing substituent in the thiophene ring being raised by ca. 40 mV by changing the alkyl substituent position from 5 to 3. The electrochemical data are in perfect agreement with the spectroscopic ones as judged from close similarity of the optically-and electrochemically-determined band gaps. The trends observed experimentally are reproduced in DFT calculations. The calculated values of ionization potentials and electron affinities are very close to the experimental ones. The highest photoluminescence quantum yield, approaching 80%, was measured for T1 compounds, whereas for T3 ones its value dropped below 20%. Time resolved photoluminescence studies consistently showed in turn shorter emission lifetimes and larger non-radiative rate constants for compounds of lower photoluminescence quantum yields. Guest/host-type single layer light emitting diodes were fabricated from the most luminescent compounds (T1 series), molecularly dispersed (1 wt%) in a matrix consisting of 70 wt% of poly(N-vinylcarbazole) and 30 wt% of 2-tert-butylphenyl-5biphenyl-1,3,4-oxadiazole. Appropriate alignment of the matrix components energy levels and those of the T1 compounds resulted in effective electroluminescence of the guest molecules. The fabricated diodes showed luminance exceeding 2600 cd/m 2 with the luminous efficiency of 0.7 cd/A. a calculated according to the formula IP = e((E ox2 +E red2 )/2 + 4.8) [eV] b calculated according to the formula EA = -e((E red1 +E ox1 )/2+ 4.8) [eV] c calculated for dichloromethane solutions

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Section: Calculationsmentioning

confidence: 99%

Diketopyrrolopyrroles disubstituted with alkylated thiophenes: effect of the donor unit size and solubilizing substituents on their redox, photo- and electroluminescence properties

et al. 2015

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“…The current technological applications of DNA span from the use of nucleic acid templates to activate enzyme cascades, and self‐assembly of nanoscale nucleic acid building blocks into mesoscale structures, to self‐organization of supramolecular DNA nanostructures acting as molecular nanomachines . DNA has been proposed as biological template for the assembly of nanoelectronic devices and nanocircuits . Moreover, DNA has been extensively investigated for the development of field‐effect transistors, chemical and biological sensors, and nanodiodes .…”

Section: Introductionmentioning

confidence: 99%

Triggering Mechanism for DNA Electrical Conductivity: Reversible Electron Transfer between DNA and Iron Oxide Nanoparticles

Magro

Baratella

Jakubec

et al. 2015

Adv Funct Materials

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A new category of iron oxide nanoparticles (SAMNs, γ-Fe2O3) allows the intimate chemical and electrical contact with DNA by direct covalent binding. On these basis, different DNA-nanoparticle architectures were developed and used as platform for studying electrical properties of DNA. The macroscopic three-dimensional nano-bio-conjugate, constituted of 5% SAMNs, 70% water and 25% DNA, showed high stability, electrochemical reversibility and, moreover, electrical conductivity (70-80 Ω cm-1). Reversible electron transfer at the interface between nanoparticles and DNA was unequivocally demonstrated by Mössbauer spectroscopy, which showed the appearance of Fe(II) atoms on nanoparticles following nano-bio-conjugate formation. This represent the first example of permanent electron exchange by DNA, as well as, of DNA conductivity at a macroscopic scale. Finally, the most probable configuration of the binding was tentatively modelled by density functional theory (DFT/UBP86/6-31+G*), showing the occurrence of electron transfer from the organic orbitals of DNA to surface exposed Fe(III) on nanoparticles, as well as the generation of defects (holes) on the DNA bases. The unequivocal demonstration of DNA conduction provides a new perspective in the five decades long debate about electrical properties of this biopolymer, further suggesting novel approaches for DNA exploitation in nano-electronics

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“…The DNA molecule, containing the genetic code of all living species, has recently become a center of great attention on the part of chemists and physicists, one of the reasons being DNA's potential use in nanoelectronic devices [1][2][3][4], both as a template for assembling nanocircuits and as an active element of such circuits. Charge migration along DNA molecules has attracted scientific interest for more than fifty years.…”

Section: Introductionmentioning

confidence: 99%

Conductivity of natural and modified DNA measured by scanning tunneling microscopy. The effect of sequence, charge and stacking

Kratochvílová¹,

Král²,

Bunček³

et al. 2008

Biophysical Chemistry

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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT AbstractThe conductivity of DNA covalently bonded to a gold surface was studied by means of the STM technique. Various single-and double-stranded 32-nucleotide-long DNA sequences were measured under ambient conditions so as to provide a better understanding of the complex process of chargecarrier transport in natural as well as chemically modified DNA molecules. The investigations focused on the role of several features of DNA structure, namely the role of the negative charge at the backbone phosphate group and the related complex effects of counterions, and of the stacking interactions between the bases in Watson-Crick and other types of base pairs. The measurements have indicated that the best conductor is DNA in its biologically most relevant double-stranded form with Watson-Crick base pairs and charged phosphates equilibrated with counterions and water. All the studied modifications, including DNA with non-Watson-Crick base pairs, the abasic form, and especially the form with phosphate charges eliminated by chemical modifications, lower the conductivity of natural DNA.

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Combined experimental and theoretical DFT study of molecular nanowires negative differential resistance and interaction with gold clusters

Cited by 22 publications

References 28 publications

Diketopyrrolopyrroles disubstituted with alkylated thiophenes: effect of the donor unit size and solubilizing substituents on their redox, photo- and electroluminescence properties

Diketopyrrolopyrroles disubstituted with alkylated thiophenes: effect of the donor unit size and solubilizing substituents on their redox, photo- and electroluminescence properties

Triggering Mechanism for DNA Electrical Conductivity: Reversible Electron Transfer between DNA and Iron Oxide Nanoparticles

Conductivity of natural and modified DNA measured by scanning tunneling microscopy. The effect of sequence, charge and stacking

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