A Class of Auxiliary Passivators for Polymer Dielectrics

Abstract

Abstract High‐electrical‐strength polymer dielectrics are essential for advanced devices with high power and/or high integration densities and film capacitors with high energy‐storage densities. Key factors affecting the polymer dielectric electrical strength are deep‐level defect states, which lead to electron and hole accumulation. Numerous deep‐level defect states lead to charge accumulation in the polymer dielectric during operation, contributing to local electric field distortion and resulting in flashover or breakdown. In this work, first‐principles calculations and experiments reveal that VH (i.e., H vacancies) in the polymer dielectric molecular chain can create defect states deep in the bandgap. RCl (R = Li, Na, K) can be used for passivating the deep‐level polymer dielectric defect states. In addition, the passivation mechanisms are analyzed. The RCl cations can passivate deep‐level defect states into shallow‐level acceptor defect states because the RCl dipole moment regulates the deep‐level defect state energy. The RCl anions can passivate deep‐level defect states into shallow‐level donor defect states by forming a stable covalent bond between carbon and lone‐pair electrons. This work supports the design of high‐electrical‐strength polymer dielectrics.

Keywords

• defect states
• DFT calculations
• passivation
• polymer dielectrics