Vocabulary for Semiconducting Polymers

Cis- (and Trans) Configuration
Given the geometry of the sp2 hybridization required for every carbon atom of a conjugated polymer chain, the arrangement of carbon atoms can follow two basically different "recipes" as shown below
Cis and trans cOnfiguratiOn
The meaning of "cis" and "trans" configuration becomes clear, but bear in mind that we also could have just a statistical arangement or some trans in mostly cis, or... . You get the point.
   
Conjugated polymer
Any polymer with alternating single- and double bonds along the chain
The general way of drawing that is —C==C—C==C—C==C—; of course always with one "something attached to every C-atom
However, looking at the three-dimensional bonding structure following from the sp2-hybrid orbitals of the carbon atom, it becomes clear that the chain cannot be perfectly linear. This allows then for variants for the same basic chemistry known as "cis" and "trans" configuaion
   
Peierls instability
See the extra module for that
   
Pi (p) - Bonds
   
Sigma (s) - Bonds
   
Trans- (and Cis) Configuration
Given the geometry of the sp2 hybridization required for every carbon atom of a conjugated polymer chain, the arrangement of carbon atoms can follow two basically different "recipes" as shown below
Cis and trans cOnfiguratiOn
The meaning of "cis" and "trans" configuration becomes clear, but bear in mind that we also could have just a statistical arangement or some trans in mostly cis, or... . You get the point.
   

With frame With frame as PDF

go to 10.4.1 Some Basics

go to Peierls Instability

© H. Föll (Semiconductors - Script)