Fig. 2
From: Recent advances in ion sensing with conducting polymers
((Reproduced with permission from Ref. [28]. Copyright 2014 Royal Society of Chemistry), and its interpretation based on a the traditional pre-DFT picture and b our DFT calculations (Adapted with permission from reference from [26]. Copyright 2019 American Chemical Society))
Optical absorption spectra of the conducting polymer poly(3,4-ethylenedioxythiophene). Representative absorption spectrum of PEDOT