Organic mixed ionic-electronic conductors (OMIECs) are materials used in fields such as bioelectronics, ion-sensors and neuromorphic computing. Thanks to their unique ability to translate between ionic and electronic signals, OMIECs are well suited for directly interfacing biological systems with electronics [1]. One of the big advantages of such organic systems, often conjugated polymers, is the large variability in chemical design. While this allows for great tunability of material properties, it also makes OMIECs very complex systems that are hard to fully understand. In order to use the full potential of OMIECs and thus drive forward the development of applications, it is therefore needed to find ways to systematically study them.

Since the ionic-electronic translation involves ion migration, redox processes linked to electronic transitions in π-systems and the thereby incurred modulation of electrical conductivity, many employed measurement techniques involve electrochemistry and spectroscopy [1]. We use a home-built tabletop setup to combine vis-NIR spectroscopy and electrochemistry with device characterization methods. Through deconvolution of the spectral data and comparing to the electrochemical data we access information about the chemical species present in the material, which can be linked to the modulation of device properties. Like this, we are able to systematically characterize various OMIECs, eventually making the development of better materials more efficient.

[1] B.D. Paulsen, K. Tybrandt, E. Stavrinidrou, J. Rivnay, Nat. Mater., 2020, 19, 13-26