Charge Hopping in Molecular Wires as a Sequence of Electron-Transfer Reactions

Berlin, Yu. A.; Hutchison, Geoffrey; Rempała, Paweł; Ratner, Mark A.; Michl, Josef

doi:10.1021/jp034225i

Cited by 213 publications

(213 citation statements)

References 61 publications

Supporting

Mentioning

206

Contrasting

Unclassified

Order By: Relevance

“…At high temperature, when the motion of the carriers can be modeled by sequences of uncorrelated hops, the mobility can be given by Equation (1): [23][24][25] m ¼ ea…”

Section: Methodsmentioning

confidence: 99%

Vibronic Coupling in Organic Semiconductors: The Case of Fused Polycyclic Benzene–Thiophene Structures

Coropceanu

Kwon

Wex

et al. 2006

Chemistry A European J

View full text Add to dashboard Cite

The nature of vibronic coupling in fused polycyclic benzene-thiophene structures has been studied using an approach that combines high-resolution gas-phase photoelectron spectroscopy measurements with first-principles quantum-mechanical calculations. The results indicate that in general the electron-vibrational coupling is stronger than the hole-vibrational coupling. In acenedithiophenes, the main contributions to the hole-vibrational coupling arise from medium- and high-frequency vibrations. In thienobisbenzothiophenes, however, the interaction of holes with low-frequency vibrations becomes significant and is larger than the corresponding electron-vibrational interaction. This finding is in striking contrast with the characteristic pattern in oligoacenes and acenedithiophenes in which the low-frequency vibrations contribute substantially only to the electron-vibrational coupling. The impact of isomerism has been studied as well.

show abstract

“…At high temperature, when the motion of the carriers can be modeled by sequences of uncorrelated hops, the mobility can be given by Equation (1): [23][24][25] m ¼ ea…”

Section: Methodsmentioning

confidence: 99%

Vibronic Coupling in Organic Semiconductors: The Case of Fused Polycyclic Benzene–Thiophene Structures

Coropceanu

Kwon

Wex

et al. 2006

Chemistry A European J

View full text Add to dashboard Cite

show abstract

“…It is worth noting that such a conclusion cannot be drawn based on the present study but it requires a detailed systematic study, which is underway in our laboratory. In the case of DNA, long-range charge transfer has been explained by a hopping mechanism; [20][21][22][23][24][25] i.e., thermal oxidation of the guanine (G) or adenine (A) bases competes with the tunneling when the bridge between the donor and acceptor is long. 25 Thymine is more difficult to oxidize so that the tunneling pathway remains dominant for longer oligomers than what one would expect if G or A bases were present.…”

Section: Dicussion and Conclusionmentioning

confidence: 99%

Charge Transfer through Single-Stranded Peptide Nucleic Acid Composed of Thymine Nucleotides

et al. 2008

View full text Add to dashboard Cite

Self-assembled monolayers (SAMs) of single-stranded peptide nucleic acids (PNAs) containing 3 to 7 thymine (T) nucleotides, a C-terminus cysteine, and an N-terminus ferrocene group were formed on gold electrodes. The existence of two redox environments for the ferrocene was detected by cyclic voltammetry and was attributed to the presence of "lying-down" and "standing-up" PNA molecules. By exploiting the chemical instability of the ferrocenium ion, electrochemical cycling was used to destroy the ferrocene of "lying-down" molecules while keeping the ferrocene in the "standing-up" molecules intact. Electrochemical measurements were used to determine the electron-transfer rate through the "standing-up" PNA molecules. The tunneling decay constant for these SAMs was determined to be about 0.9 Å -1 . IntroductionThe interest in self-assembled monolayers (SAMs) 1,2 of nucleic acids has increased recently, largely because of their potential applications in molecular electronics, 3 materials science, 4 molecular recognition, 5 biotechnology, and biosensor development. [6][7][8] An understanding of the charge transport (CT) through such SAMs is needed to realize their potential in molecular electronics and biosensing. The past decade has seen progress in understanding charge transfer through deoxyribonucleic acid (DNA), which is believed to occur through either a superexchange mechanism, 9-19 which dominates at short distances, or a hopping mechanism, 20-25 which dominates at large distances.The weak distance dependence of the charge hopping mechanism and its prevalence in duplex DNA systems have motivated the exploration of charge transfer through DNA and its promise for molecular electronics by a large number of different research groups. Nevertheless, only a few research groups have studied CT in DNA monolayers, probably because of the difficulties in creating well-defined DNA assemblies on a metal surface. [26][27][28] For example, Hartwich et al. 29 used cyclic voltammetry to characterize charge transfer in mixed monolayers of DNA having a pyrroloquinoline-quinone redox probe attached to DNA through a spacer and linked to an Au(111) surface through an ethane-thiol linker. These studies determined that the CT rate constant for a 12-base-pair (bp) DNA duplex was 1.5 s -1 , while for the same duplex containing two mismatches it was 0.6 s -1 , and that charge transfer could not be detected for single-stranded (ss) DNA at a scan rate of >10 mV s -1 . Liu et al. 30 argued that CT through a monolayer of a 30-bp double-stranded (ds) DNA takes place through the nucleobase stack and does not involve the DNA backbone. They based their argument on the fact that the rate constant for CT of 30 s -1 was not affected by breaks in the sugar-phosphate backbone and was too small to be measured when a mismatch was introduced in the ds DNA. Interestingly, a similar rate constant for CT was measured for a monolayer of a 15-bp ds DNA. 31 CT rate constants for ss oligonucleotides are also quite high. For example, Kraatz and collaborators r...

show abstract

“…Such an understanding is also crucial for the future application of carboranes in molecularscale electronics. It has recently been predicted [13][14][15][16] that r-bonded carbon cage structures can be used as an effective electron tunnel barrier in molecular-scale electronic circuits.…”

Section: Introductionmentioning

confidence: 99%