n‐Type Glycolated Imide‐Fused Polycyclic Aromatic Hydrocarbons with High Capacity for Liquid/Solid‐Electrolyte‐based Electrochemical Devices

Abstract Currently, n‐type small‐molecule mixed ionic‐electronic conductors remain less explored and their molecular design rules are not mature enough. Herein, two n‐type glycolated imide‐fused polycyclic aromatic hydrocarbons (IPAHs), d‐gdiPDI and t‐gdiPDI, are developed to probe the effects of molecular conformation on the electronic, electrochemical, morphological, and coupled ionic‐electronic transport properties. It is found that the highly twisted scaffold in d‐gdiPDI, compared to the nearly planar one of t‐gdiPDI, has a strong positive effect on the charge storage properties and thus the performance of organic electrochemical transistors (OECTs). d‐gdiPDI exhibits a volumetric capacitance of 657 F cm⁻³, obviously outperforming that of t‐gdiPDI (261 F cm⁻³), which is the highest value reported to date for small‐molecule OECT materials. Moreover, a high charge‐storage capacity of up to 479 F g⁻¹ is observed for d‐gdiPDI. Arising from such high ionic‐electronic coupling characteristic, d‐gdiPDI‐based OECTs present a ≈2 × times higher geometry‐normalized transconductance (g_m,norm) of 105.3 mS cm⁻¹ relative to that of t‐gdiPDI counterparts. Significantly, further application of d‐gdiPDI in solid‐electrolyte OECTs delivers a g_m,norm of 142.4 mS cm⁻¹. These findings indicate that IPAHs are very promising candidates for n‐type small‐molecule OECTs and highlight the superiority of twisting conformation manipulation in materials design toward high‐performance electrochemical devices.