Spectroscopic Tools to Investigate the Electrochemical Doping Kinetics and Efficiency in Organic Semiconductors

Understanding the electrochemical doping of organic semiconductors plays a crucial role in the current development of organic electronics. In this short review, we present how temperature- and time- dependent visible-near-infrared (Vis-NIR) spectro-electrochemistry and terahertz spectroscopy, combined with multivariate curve resolution analysis, can inform on the fundamental mechanisms governing the doping kinetics and efficiency of two archetypal semiconducting polymers (PEDOT and P3HT). We highlight the experimental procedures and data analysis performed to access (i) the thermodynamic parameters driving the extent and dynamics of electrochemical reactions in doped systems and (ii) how the density and nature of charged species (polarons, bipolarons) impact the charge carrier delocalization, effective THz mobility and hence short-range conductivity.