Multimodal Operando Characterization Unravels Polaron Accumulation and Ion Dynamics in High-Stability Ambipolar OECTs

Ruizhe Wang^a^,^b^,^c, Gang Wang^a, Hengda Sun^a, Kai Xu^c

^aState Key Laboratory of Advanced Fiber Materials, College of Materials Science and Engineering, Donghua University, China

^bInstituto de Tecnología Química, Universitat Politècnica de València–Consejo Superior de Investigaciones Científicas, Spain.

^cState Key Laboratory of Metastable Materials Science and Technology, Center for Extreme Deformation Research, Yanshan University, China

Materials for Sustainable Development Conference (MATSUS)
Proceedings of MATSUS Fall 2026 Conference (MATSUSFall26)

D4 Iontronics

Palma, Spain, 2026 October 26th - 30th

Organizers: Roberto Fenollosa Esteve and Francesco Rossella

Poster, Ruizhe Wang, 536
Publication date: 22nd July 2026

Understanding the coupling between charge formation, ion transport, and structural evolution is essential for improving the operational stability of ambipolar organic electrochemical transistors (OECTs). Here, we investigate P-6O, a copolymer containing naphthalenediimide and dialkoxybithiazole units with oligo(ethylene glycol) side chains, using complementary operando characterization methods. Optical absorption spectroscopy and electron paramagnetic resonance, supported by density functional theory calculations, identify the formation of p- and n-type polarons and reveal their relatively localized electronic character. Temperature-dependent electron paramagnetic resonance and attenuated total reflection Fourier transform infrared spectroscopy further elucidate the influence of the ionic environment and noncovalent polymer–electrolyte interactions. Operando X-ray photoelectron spectroscopy tracks the opposing motion of cations and anions during electrochemical doping, while grazing-incidence wide-angle X-ray scattering reveals limited structural changes. Despite its low backbone planarity and localized polarons, P-6O supports stable ambipolar transistor operation over 1000 pulse cycles. These findings connect charge-state evolution and compensating ion exchange with morphological stability, highlighting ion dynamics as a key consideration in the design of durable organic mixed ionic–electronic conductors and ambipolar OECTs.

References:

[1] Zheng, H.; Wang, R.; Ma, H.; Li, X.; Ye, G.; Zhao, Y.; Zhang, P.; Wang, G.; Sun, H.; Liang, Y.; Fabiano, S.; Xu, K. Multimodal operando characterization unravels polaron accumulation and ion dynamics in high-stability ambipolar OECTs. Sci. Adv. 2026, 12, eaea9786.

Acknowledgements:

We thank the Beijing Synchrotron Radiation Facility (BSRF-1W1A) and beamline BL02U2 at the Shanghai Synchrotron Radiation Facility for assistance with GIWAXS measurements. Financial support was provided by the National Natural Science Foundation of China (52173156 and 52373282); Yanzhao Huangjintai Jucai Jihua (HY2024050011); the Foundation of Yanshan University (1050030 and 8190299); the Jiangxi Provincial Natural Science Foundation (20242BAB21001 and 20242BCE0074); the Fundamental Research Funds for the Central Universities (2232025A-06 and 2232024Y-01); the DHU Distinguished Young Professor Program (LZB2025002); and the Science and Technology Commission of Shanghai Municipality (23ZR1402000 and 24520713100).

nanoGe is a prestigious brand of successful science conferences that are developed along the year in different areas of the world since 2009. Our worldwide conferences cover cutting-edge materials topics like perovskite solar cells, photovoltaics, optoelectronics, solar fuel conversion, surface science, catalysis and two-dimensional materials, among many others.

MATSUS

Previously nanoGe Spring Meeting (NSM) and nanoGe Fall Meeting (NFM), MATSUS is a multiple symposia conference focused on a broad set of topics of advanced materials preparation, their fundamental properties, and their applications, in fields such as renewable energy, photovoltaics, lighting, semiconductor quantum dots, 2-D materials synthesis, charge carriers dynamics, microscopy and spectroscopy semiconductors fundamentals, etc.

International Conference on Hybrid and Organic Photovoltaics

International Conference on Hybrid and Organic Photovoltaics (HOPV) is celebrated yearly in May. The main topics are the development, function and modeling of materials and devices for hybrid and organic solar cells. The field is now dominated by perovskite solar cells but also other hybrid technologies, as organic solar cells, quantum dot solar cells, and dye-sensitized solar cells and their integration into devices for photoelectrochemical solar fuel production.

Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics

The main topics of the Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics (IPEROP) are discussed every year in Asia-Pacific for gathering the recent advances in the fields of material preparation, modeling and fabrication of perovskite and hybrid and organic materials. Photovoltaic devices are analyzed from fundamental physics and materials properties to a broad set of applications. The conference also covers the developments of perovskite optoelectronics, including light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.

International Conference on Perovskite Thin Film Photovoltaics Perovskite Photonics and Optoelectronics

The International Conference on Perovskite Thin Film Photovoltaics Perovskite Photonics and Optoelectronics (NIPHO) is the best place to hear the latest developments in perovskite solar cells as well as on recent advances in the fields of perovskite light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.