Effect of Ammonium Salt on Conjugated Polyelectrolyte as an Interlayer for Organic–Inorganic Hybrid Perovskite Memristors

Memristors are promising candidates for next-generation non-volatile memory devices, offering low power consumption and high-speed switching capabilities. However, conventional metal oxide-based memristors are constrained by fabrication complexity and high costs, limiting their commercial viability. Organic–inorganic hybrid perovskites (OIHPs), known for their facile solution processability and unique ionic–electronic conductivity, provide an attractive alternative. This study presents a conjugated polyelectrolyte (CPE), PhNa-1T, as an interlayer for OIHP memristors to enhance the high-resistance state (HRS) performance. A post-treatment process using n-octylammonium bromide (OABr) was further applied to optimize the interlayer properties. Devices treated with PhNa-1T/OABr achieved a significantly improved ON/OFF ratio of 2150, compared to 197 for untreated devices. Systematic characterization revealed that OABr treatment improved film morphology, reduced crystallite strain, and optimized energy level alignment, thereby reinforcing the Schottky barrier and minimizing current leakage. These findings highlight the potential of tailored interlayer engineering to improve OIHP-based memristor performance, offering promising prospects for applications in non-volatile memory technologies.