Insulating Electrets Converted from Organic Semiconductor for High‐Performance Transistors, Memories, and Artificial Synapses

Abstract Electrets are commonly used charged insulators that generate a quasi‐permanent electric field. However, when conventional electrets come into direct contact with semiconductors, the energy level mismatch at the interface results in low memory speed and high energy consumption of electret devices due to both charge injection and storage being non‐conducive. To address this, the n‐type semiconductor N,N′‐dioctyl‐3,4,9,10‐perylene tetracarboxylic diimide (C₈‐PTCDI) is converted to C₈‐PTCDI (D) via oxygen degradation. The resulting C₈‐PTCDI (D) electrets, when charged using an electric field and/or light, retain the energy level of the n‐type semiconductors to facilitate charge trapping. They also exhibit deeper trap energy levels and increased trap density, thereby enhancing the sheet charge density of C₈‐PTCDI (D) electrets (7.47 × 10¹² cm⁻²). As a result, devices based on n‐type electrets demonstrate lower operation voltage (2 V) of transistors, lower operation voltage (20 V) of memories, and lower energy consumption (3.5 fJ per spike) of artificial synapses compared to those without n‐type electrets.