Charge transport efficient

Incorporation of the modified nucleotide bases enables us to modulate the DNA properties that are extremely important to the charge transport efficiency. The data obtained by these experiments provides a much deeper insight and understandingof the mechanism of DNA mediated charge transport. 

The charge generation and charge transport efficiency of a polymer can also be measured separately by other techniques. For example, laser flash photolysis can measure the charge generation efficiency directly, if the generated electron or hole (anion or cation) has a distinct absorp-... 

Increase of the doping level, N, leads to a significant increase of mobility, up to i = 10 cm V ls but also leads to a simultaneous increase of the conductivity, up to values of the order of 10" Scm l. Large ohmic currents arc therefore expected, which increase loff currents and dramatically reduce the dynamic ratio of the corresponding devices. Hence, simultaneous increase of mobility and conductivity invalidates this approach to the improvement of charge transport efficiency in conjugated polymers and disordered materials. 

A well-studied binary system of discotic liquid crystal toward high carrier mobility systems is a blend of two types of triphenylene-based compounds (Fig. 8.5). These two compounds were mixed in expectation to give a new semiconducting system that exhibits enhancement of charge transport efficiency. The concept is based on Complimentary Polytopic Interaction (CPI) [16-18]. 

Niu S and Mauzerall D 1996 Fast and efficient charge transport across a lipid bilayer is electronically mediated by Cyf, fullerene aggregates J. Am. Chem. Soc. 118 5791-5... 

A small amount of work has been undertaken to explore polymer blends, where one polymer is chosen for its charge transport characteristics and the other for its luminescence. Best efficiencies are obtained when small concentrations of the emitter are present in the transporting polymer, e.g. blending one PPV deriva-... 

In the perfectly paired double strand 22, the yield of product PGgg> which indicates the amount of charge that has reached the hole trap GGG, is 68%. But if the intermediate G C base pair is exchanged by a G T mismatch, the efficiency of the charge transport drops to 23%. With an abasic site (H) opposite to G the hole transport nearly stops at this mismatched site (Fig. 15). We have explained this influence of a mismatch on the efficiency of the charge transport by a proton transfer from the guanine radical cation (G2 +)... 

DNA-mediated charge transport has been a hot topic in chemistry for the last decade. Studies of DNA-mediated guanine radical cation (hole) transport are often focused on the efficiency of the transport between two guanines separated by a large distance, through the /r-stack of DNA base pairs [1-14]. The efficiency of the hole transport could be easily determined if one knew the distance between the hole donor and acceptor, the relative number of holes that reach the acceptor, and the time required for the transport. 

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