Operando Characterization of Organic Mixed Ionic/Electronic Conducting Materials

Abstract

Operando characterization plays an important role in revealing the structure− property relationships of organic mixed ionic/electronic conductors (OMIECs), enabling the direct observation of dynamic changes during device operation and thus guiding the development of new materials. This review focuses on the application of different operando characterization techniques in the study of OMIECs, highlighting the time-dependent and bias-dependent structure, composition, and morphology information extracted from these techniques. We first illustrate the needs, requirements, and challenges of operando characterization then provide an overview of relevant experimental techniques, including spectroscopy, scattering, microbalance, microprobe, and electron microscopy. We also compare different in silico methods and discuss the interplay of these computational methods with experimental techniques. Finally, we provide an outlook on the future development of operando for OMIEC-based devices and look toward multimodal operando techniques for more comprehensive and accurate description of OMIECs.

In operando nanomechanical mapping of PEDOT:PSS thin films in electrolyte solutions with bimodal AFM

“…Organic semiconductor devices are used in a variety of applications. [1][2][3][4] Among these, organic field effect transistors are promising in biomolecular sensing and biomedicine. [4][5][6][7] In mixed ionic electronic materials, the properties of the organic materials are controlled by electrochemical doping.…”

Mixed Ionic–Electronic Conduction, a Multifunctional Property in Organic Conductors

“…For a detailed overview on the current understanding of microstructural changes during device operation, readers are pointed to a recent review by Wu et al. [ 28 ]…”

“…It is expected that the future deployment of operando and in situ characterization techniques will facilitate the development of such design rules. [ 28 ] In particular, techniques such as X‐ray scattering combined with electrochemical measurements could elucidate the complex dynamics which arise during charging, many of which are still relatively unknown. Additionally, spectroscopic techniques including visible and infrared absorption spectroscopy and Raman spectroscopy provide insights into both ordered and disordered domains of these materials, although detailed modeling is often required to link these changes back to the OMIEC structure.…”

“…[26] Furthermore, the exact nature of interaction between penetrating ions and the OMIEC is poorly understood and perhaps beyond the scope of this perspective. For a detailed overview on the current understanding of microstructural changes during device operation, readers are pointed to a recent review by Wu et al [28]…”

Hybrid Organic-Inorganic Materials and Interfaces With Mixed Ionic-Electronic Transport Properties: Advances in Experimental and Theoretical Approaches

“…There are a lot of recent examples of h OI materials with promising mixed ionic-electronic transport properties in different applications such as lithium and sodium-ion battery electrode ( Sengodu and Deshmukh, 2015 ) and bio-electronic materials ( Kousseff et al, 2022 ; Kukhta et al, 2022 ). There are also recent reviews on the most relevant and popular techniques that can be useful to characterize experimentally the mixed ionic-electronic transport in h OI materials ( Romero et al, 2020 ; Wu et al, 2022 ). However, there are still very few reports dealing with computational simulation approaches of mixed ionic-electronic transport of h OI materials and interfaces mainly due to their extremely demanding computational cost.…”