In-Situ TEM Studies of Halide Perovskite Memristors: Mechanistic Insights and Future Directions

Halide perovskite memristors are promising for low-power memory and neuromorphic computing because their mixed ionic-electronic nature enables resistive switching at small voltages and currents. However, the microscopic origin of the switching mechanism remains unclear, as most mechanisms are still inferred from electrical measurements or post-mortem characterization. In-situ transmission electron microscopy (TEM) offers a direct way to correlate electrical bias with real-time structural and chemical evolution at the nanoscale. This mini review discusses how in situ and operando TEM can help to clarify switching pathways in halide perovskite memristors. We first outline the various processes that enable resistive switching such as ionic migration, electrochemical reactions, and microstructural transformations. We then summarize recent advances in low-dose TEM, beam-damage mitigation, and biasing platforms that make operando studies of beam-sensitive perovskites more feasible. Finally, we summarize the key current insights from biased TEM studies and early memristor-specific reports and highlight key challenges and future opportunities for mechanism-guided device design.