Novel crosslinkable high-k copolymer dielectrics for high-energy-density capacitors and organic field-effect transistor applications†
High-dielectric-constant (high-k) polymers are highly desirable for energy storage and dielectric applications in power systems and microelectronic devices because of their easy processing and flexibility. However, the enhancement of k is usually at the cost of other undesirable properties such as increase of dielectric loss and leakage currents and decrease of breakdown strength. Herein, using reversible-addition fragmentation chain transfer (RAFT) polymerization, we report a series of novel low-temperature crosslinkable high-k copolymers, poly(2-(methylsulfonyl)ethyl methacrylate-co-glycidyl methacrylate) (poly(MSEMA-co-GMA)), which exhibit k values about 9–12. The crosslinking significantly enhances the breakdown strength (Eb ≈ 500 MV m−1), suppresses the leakage currents and improves the solvent resistance. The excellent dielectric performance makes the copolymers have both high energy storage capability and high energy efficiency. The discharged energy density reached 12.5 J cm−3 at 500 MV m−1. Noticeably, an efficiency higher than 85% was maintained even at a high field of 400 MV m−1, which is much higher than those of poly(vinylidene fluoride) (PVDF) based ferroelectric polymers with comparable k. Furthermore, the poly(MSEMA-co-GMA) copolymers were successfully applied as dielectric layers for organic field-effect transistors (OFETs) to realize low-voltage operation.