Tracking ion mediated changes in the optical properties of a polymeric mixed ionic-electronic conductor: an application for a chemical sensor system

摘要

In this study, we use photoinduced absorption (PIA) spectroscopy to show that the triplet exciton properties of an oligo(ethylene oxide) (OEO) grafted conjugated polymer (PPP-R10) are very sensitive to the presence of ionic species. Investigations were performed on thin spin-cast films of this polymeric mixed ionic-electronic conductor. Since the ion-coordinating side-chains are directly attached to the conjugated backbone, an ion induced order-disorder transition affects the characteristics of the conjugated polymer, which is observable as a blue shift in the pi-pi* absorption, the triplet exciton absorption spectra, and also manifests in other triplet exciton properties, like their lifetimes and the bimolecular annihilation parameter. Based on the sensitivity of the triplet exciton properties such polymers can be envisioned in the application in chemical sensor systems.