Oligothiophenes charge transfer

Only the nitro-substituted oligothiophenes display large bathochromic shifts, large Stokes shifts, high fluorescent quantum yields, and long lifetimes for excited states. As for the other substituents, the trend is mostly noticeable for the short oligomers like terthiophenes and seems to disappear for sexithiophenes. As can be inferred from their solvatochromic effect, an intramolecular charge transfer takes place in the excited states of these molecules. 

Ammonium phosphomolybdate, (NH4)3PMo,2O40, when suspended in asbestos, can be used (in acid or neutral conditions) to separate K+, Rb+, Cs+, Ag+ and T1+ cations from solution [75]. Conducting charge transfer complexes containing oligothiophene cations and PM012O40 anions confer new properties on polymers to which they are attached. 

A. Petrella, J. Cremer, L. De Cola, P. Bauerle and R. M. WiUiams, Charge transfer processes in conjugated triarylamine-oligothiophene-perylenemonoimide dendrimers, J. Phys. Chem. A, 109, 11687-11695 (2005). 

Linear and branched oligothiophene-5, -dioxides have been employed as electron acceptor materials in photovoltaic devices based on blends with poly(3-hexylthiophene). Photoinduced charge transfer was demonstrated from photoluminescence spectroscopy and from enhanced photovoltaic performance exhibited by the blended cells with respect to those with the pure polymer as active layer [86-92],... 

The oligothiophene materials (both as solids and in solution) can be doped in a manner similar to the polythiophenes, using also related chemical species of dopants. Since the oligothiophenes are low molecular-weight materials, they readily form charge-transfer (CT) complex crystals with an appropriate acceptor... 

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