Stable Halide Perovskite Memristor Utilizing Innovative Silver/Bismuth Electrode as an Alternative to Gold

Perovskite memristors hold great promise for neuromorphic computing due to their ease of fabrication and sensitivity to light and electrical stimuli. However, the common use of expensive metal electrodes, such as gold (Au) and unstable silver (Ag), limits their stability and broader application. In this study, a cost-effective perovskite memristor utilizing a novel Ag/Bismuth (Ag/Bi) bilayer electrode, which serves as a viable alternative to Au while maintaining excellent performance, is presented. This design prevents electrochemical reactions and the formation of unstable metallic filaments, enabling controlled mixed electronic/ionic conductivity. Moreover, the low work function of the Ag/Bi bilayer reduces the built-in voltage, facilitating the formation and retention of conductive filaments, which improves device performance and stability. The memristor exhibits a high on/off ratio (10²), excellent endurance (≈800 cycles), long retention (>10⁴ s), and storage stability comparable to Au-based devices. Furthermore, it demonstrates neuromorphic synaptic behaviors, including long- and short-term plasticity (STP), potentiation/depression, and spike-timing-dependent plasticity (STDP). When integrated into a spiking neural network (SNN) for digital image recognition using the MNIST dataset, the device achieves an accuracy of 86.68%. This work demonstrates the potential of the cost-effective Ag/Bi bilayer electrode in enhancing the stability and performance of perovskite memristors.