Electron-Deficient Polycyclic Molecules via Ring Fusion for n-Type Organic Electrochemical Transistors

The primary challenge for n-type small-molecule organic electrochemical transistors (OECTs) is to improve their electron mobilities and thus the key figure of merit mu C*. Nevertheless, few reports in OECTs have specially proposed to address this issue. Herein, we report a 10-ring-fused polycyclic pi-system consisting of the core of naphthalene bis-isatin dimer and the terminal moieties of rhodanine, which features intramolecular noncovalent interactions, high pi-delocalization and strong electron-deficient characteristics. We find that this extended pi-conjugated system using the ring fusion strategy displays improved electron mobilities up to 0.043 cm(2) V-1 s(-1) compared to our previously reported small molecule gNR, and thereby leads to a remarkable mu C* of 10.3 F cm(-1) V-1 s(-1) in n-type OECTs, which is the highest value reported to date for small-molecule OECTs. This work highlights the importance of pi-conjugation extension in polycyclic-fused molecules for enhancing the performance of n-type small-molecule OECTs.

Automated summary

The primary challenge for n-type small-molecule organic electrochemical transistors (OECTs) is to improve electron mobility. In this study, a 10-ring-fused polycyclic pi-system was reported, which showed intramolecular noncovalent interactions, high pi-delocalization, and strong electron-deficient characteristics. The extended pi-conjugated system using the ring fusion strategy displayed improved electron mobility and achieved the highest mu C* value of 10.3 F cm(-1) V-1 s(-1) in n-type OECTs reported to date. This work highlights the importance of pi-conjugation extension in enhancing the performance of n-type small-molecule OECTs.