A new aspect of cyclopentadithiophene based polymers: narrow band gap polymers upon protonation†
Abstract
A new aspect of cyclopentadithiophene (CPDT) based conjugated polymers was reported. CPDT units in conjugated polymers can be facilely protonated with a significant change in optical and electronic properties. The protonation was confirmed by NMR spectra studies and the remarkable decrease of the energy band-gap was attributed to charge separation upon protonation.