Temperature resistant amorphous polyimides with high intrinsic permittivity for electronic applications

High-dielectric-constant (high-k) polymers are highly desirable for high energy density capacitors and low-voltage organic thin-film transistors (OTFTs). However, conventional high-k polymers suffer from low temperature resistance or crystalline state, hampering their applications in electronic devices in general environments. Herein, by accurate monomer design and mild polycondensation, we synthesize a new polyimide (STP-PI) featuring amorphous state, intrinsic high-k, very high thermal stability, and self-standing properties. Having polar side groups and rigid twisty backbones, the STP-PI exhibits both high and stable permittivity (5.2 similar to 6.0 from 1 MHz to 100 Hz) and excellent thermal stability (T-d5% > 450 degrees C and T-g > 300 degrees C), superior to its counterpart without the polar side group. When applied for energy storage, STP-PI delivers a discharged energy density of 3.68 J cm(-3) with discharge efficiency of 84% at 350 MV m(-1) even at 200 degrees C, which makes a record among the state-of-the-art performance of instinct polymer dielectrics. When applied in low-voltage OTFTs as the dielectric layers, the devices show a low threshold voltage of -0.30 V and mobility value of 4.03 cm(2) V-1 s(-1). The design strategy paves a way of making high-k polyimides for high temperature energy storage and electronic applications.

Automated summary

By accurate design and polycondensation, a new high-k polyimide with amorphous state, high thermal stability, and self-standing properties is synthesized. It exhibits both high and stable permittivity and excellent thermal stability, making it suitable for energy storage and low-voltage electronic applications even at high temperature.