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 smallmolecule 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.

Materials design and applications of n-type and ambipolar organic electrochemical transistors

“…Only three reported n-type materials, BBL:PEI, 48 PBFDO 31 (Fig. 3b) and t-gdiPDI 32 (Fig. 5b), work in the depletion mode.…”

“…5b). 32 They aimed to investigate the changes in backbone conformation on OECT performance. DFT calculations revealed that d-gdiPDI exhibits a highly twisted structure, whereas t-gdiPDI possesses a rigid and nearly planar backbone.…”

“…These advancements include the development of a no-side-chain polymer BBL, the introduction of conductive polymer PBFDO, 31 the proposal of “doped state engineering”, 14 and the use of small molecule materials. 32,33 Among these materials, PBFDO has shown impressive performance. 31 However, PBFDO possesses a hydrophobic backbone with no hydrophilic side chains and it only shows good performance in thin films (∼50 nm).…”

Aldol Condensation for the Construction of Organic Functional Materials

“…Yue et al. dedicated to developing n‐type small molecule functional materials as highly efficient mixed ionic and electronic conductors in OECTs [27b,32] . We introduced a new series of rigid‐rod electron‐deficient A=A structural small molecules based on naphthalene lactone and its oligomers [33] .…”

Assessment of the Testing Methods for Evaluating the Performance of Organic Electrochemical Transistors

“…Very different parameters (such as speed and the type of voltage) have been applied during the measurements of OECTs, and very different results have been obtained in the literature even for similar OECTs (Table S1). ,− Therefore, it is necessary to clarify the effects of the testing methods and parameters on the measured performance of OECTs.…”