Polarons in Conjugated Polymers

The polaron is characterized by the reversal of bond alternation, which, in the case of poly thiophene, extends over five monomer units [30-32], and the appearance of two localized states in the band gap ). These states have been indeed observed by UV-VIS absorption of both oligomers and polymers, in solution [33-40] and in the solid state [41 —451. 

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For spin-1/2 excitations such as electrons and holes in normal semiconductors or polarons in conjugated polymers, a single resonance is found centered at the Field... 

The stress we lay on the difference between optic and acoustic deformation is a reaction to the enormous literature on exclusively optic polarons in conjugated polymers. Yet as the Davydov Soliton and SWAP show, it is the acoustic deformation which dominates the motion of the polaron. In so far as it is motion which is the essential quality of a Soliton, it is the Acoustic deformation which it is essential to consider. In reality... 

Beljonne, D., et al. 2001. Optical signature of delocalized polarons in conjugated polymers. Adv Funct Mater 11 229. 

Miranda, P.B., D. Moses, and A.J. Heeger. 2001. Ultrafast photogeneration of charged polarons in conjugated polymers. Phys Rev B 64 081201. 

The effects of interchain interactions on the stabilization of polarons in conjugated polymers have been considered in density functional three-dimensional calculations performed on PPV [41 ]. These calculations indicate that the polaronic effects as modeled in the isolated chain models may be considerably less strong when interchain interactions are taken into account, and the same concern has been raised by Emin [42,43]. 

Research interests of Dr. Krinichnyi resulting from the practical application of multifrequency EPR spectroscopy are concerned with relaxation and dynamics of nonlinear charge carriers, solitons, and polarons in conjugated polymers and their nanocomposites, mechanism of charge transport in molecular crystals, spin phenomena in condensed systems, and organic molecular electronics, photonics, and spintronics. Since 1992, he is member of the International EPR (ESR) Society Thirteen Russian and International scientific projects were carried out under his direct guidance as principal... 

The electrical conductivity in the solid state is determined by the product of the carrier concentration and the carrier mobility. In conjugated polymers both entities are material dependent and, i.e., are different for electrons and holes. Electrons or holes placed on a conjugated polymer lead to a relaxation of the surrounding lattice, forming so-called polarons which can be positive or negative. Therefore, the conductivity, o, is the sum of both the conductivity of positive (P+) and negative polarons (P ) ... 

Refs. [i] Chance RR, Boundreaux DS, Bredas J-L, Silbey R (1986) Solitons, polarons and bipolarons in conjugated polymers. In Skotheim TA (Ed) Handbook of conducting polymers, vol. 2, Marcel Dekker, p 825 [ii] Inzelt G (1994) Mechanism of charge transport in polymer-modified electrodes. In Bard AJ (Ed) Electroanalytical chemistry, vol. 18, Marcel Dekker [iii] Lyons MEG (1994) Charge percolation in electroactive polymers. In Lyons MEG (ed) Electroactive polymer electrochemistry, Parti, Plenum, New York, p 1... 

It is worth stressing that the SWAP and the Holstein Polaron can exist in any polymer, for example in polyethylene or nylon, as well as in conjugated polymers. 

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