Characterisation of PPy

From this spectroscopic analysis we learn that the very strong Raiman line near 1570 cm arises from fl (i.e. from the collective motion which uniquely implies the delocalisation of n electrons along the chain or, in orher words, from the collective motion which modulates the energy gap) is a probe for judging delocalisation length which can be numerically measured by the effective conjugation parameter F. From the frequency and intensity dispersions one has also the way to understand the observed Raman spectrum of the doped material and to describe its chemical nature. 

The fact that the doping induced IR spectrum fits the calculated dispersions U/F and 1/Ffi at f °P is a proof that a qui- 

The Raman spectrum of the doped material shows the existence of a residual undoped substance with shorter effective conjugation length.  

Polythiophene is a material which is the center of interest of many groups for its possible applications. It shows high conductivity when doped [110], large third order non linear optical properties [111] and it has been used as a semiconducting active material in the first attempts to build MISFET devices [112]. Of more relevant practical importance is the fact that its alkyl-derivatives are soluble thus opening new horizons for workable polyconjugated polymers. 

Because of its relevance in possible technological applications many oligomers of Th have been the center of great interest as models or as substitutes of PTh. 

---