Metal Porphyrin-Terminated Hyperbranched Polyimides for Resistive Switching in Nonvolatile Memory Devices

Polymer resistive random-access memory (RRAM) holds great promise for flexible wearable electronics and artificial intelligence, yet its development is hindered by chain entanglement and intermolecular interactions, leading to processing challenges, high operating voltages, and unstable switching parameters. Herein, metal-porphyrin-terminated hyperbranched polyimides (ATPP@HBPI, (Zn)ATPP@HBPI, and (Cu)ATPP@HBPI) were synthesized. The hyperbranched structure mitigates intermolecular interactions, while ionic doping modulates conductivity, and the synergistic effect of ions and electrons optimizes resistive switching behavior. Devices based on ATPP@HBPI and (Cu)ATPP@HBPI exhibited nonvolatile write-once-read-many (WORM) characteristics, whereas (Zn)ATPP@HBPI displayed volatile static random-access memory (SRAM) features. The devices demonstrated threshold voltages of -1.88 to -2.60 V and ON/OFF current ratios of 10⁴-10⁵. Mechanistic analysis revealed that nonvolatile switching is dominated by carrier trapping, while the Zn "bridge" effect enables volatile behavior via dynamic charge balance. This study provides a new material platform and mechanistic insight for advancing high-density flexible organic memory devices toward practical applications.