Green Synthesis of Lactone-Based Conjugated Polymers for n-Type Organic Electrochemical Transistors

As new and better materials are implemented for organic electrochemical transistors (OECTs), it becomes increasingly important to adopt more economic and environmentally friendly synthesis pathways with respect to conventional transition-metal-catalyzed polymerizations. Herein, a series of novel n-type donor-acceptor-conjugated polymers based on glycolated lactone and bis-isatin units are reported. All the polymers are synthesized via green and metal-free aldol polymerization. The strong electron-deficient lactone-building blocks provide low-lying lowest unoccupied molecular orbital (LUMO) and the rigid backbone needed for efficient electron mobility up to 0.07 cm(2) V-1 s(-1). Instead, polar atoms in the backbone and ethylene glycol side chains contribute to the ionic conductivity. The resulting OECTs exhibit a normalized maximum transconductance g(m,norm) of 0.8 S cm(-1) and a mu C* of 6.7 F cm(-1) V-1 s(-1). Data on the microstructure show that such device performance originates from a unique porous morphology together with a highly disordered amorphous microstructure, leading to efficient ion-to-electron coupling. Overall, the design strategy provides an inexpensive and metal-free polymerization route for high-performing n-type OECTs.

Automated summary

This study reports a series of novel donor-acceptor-conjugated polymers for n-type organic electrochemical transistors (OECTs) synthesized through an economic and environmentally friendly method. The polymers exhibit high electron mobility and ionic conductivity, resulting in high-performance OECTs. Analysis of the microstructure of the devices reveals the reasons behind their superior performance. The design strategy provides a metal-free and inexpensive route for synthesizing n-type OECTs.