Wu Ruiheng, Meli Dilara, Strzalka Joseph, Narayanan Suresh, Zhang Qingteng, Paulsen Bryan D, Rivnay Jonathan, Takacs Christopher J
Department of Chemistry, Northwestern University, Evanston, IL, USA.
Department of Materials Science and Engineering, Northwestern University, Evanston, IL, USA.
Nat Mater. 2024 May;23(5):648-655. doi: 10.1038/s41563-024-01813-3. Epub 2024 Feb 26.
Understanding the structural and dynamic properties of disordered systems at the mesoscale is crucial. This is particularly important in organic mixed ionic-electronic conductors (OMIECs), which undergo significant and complex structural changes when operated in an electrolyte. In this study, we investigate the mesoscale strain, reversibility and dynamics of a model OMIEC material under external electrochemical potential using operando X-ray photon correlation spectroscopy. Our results reveal that strain and structural hysteresis depend on the sample's cycling history, establishing a comprehensive kinetic sequence bridging the macroscopic and microscopic behaviours of OMIECs. Furthermore, we uncover the equilibrium and non-equilibrium dynamics of charge carriers and material-doping states, highlighting the unexpected coupling between charge carrier dynamics and mesoscale order. These findings advance our understanding of the structure-dynamics-function relationships in OMIECs, opening pathways for designing and engineering materials with improved performance and functionality in non-equilibrium states during device operation.
了解中尺度无序系统的结构和动力学性质至关重要。这在有机混合离子-电子导体（OMIECs）中尤为重要，因为它们在电解质中运行时会发生显著且复杂的结构变化。在本研究中，我们使用原位X射线光子相关光谱研究了一种模型OMIEC材料在外部电化学势下的中尺度应变、可逆性和动力学。我们的结果表明，应变和结构滞后取决于样品的循环历史，建立了一个连接OMIEC宏观和微观行为的综合动力学序列。此外，我们揭示了电荷载流子和材料掺杂状态的平衡和非平衡动力学，突出了电荷载流子动力学与中尺度有序之间意想不到的耦合。这些发现推进了我们对OMIEC中结构-动力学-功能关系的理解，为设计和制造在器件运行的非平衡状态下具有改进性能和功能的材料开辟了途径。
