Layered double perovskite PA₄AgBiBr₈-based diffusive memristor for highly sensitive and prompt artificial nociceptive application

The sensory nociceptive functions emulated by diffusive memristors (DM) have progressed significantly through the employment of lead-based halide perovskites. Herein, we have fabricated memristor devices consisting of two-dimensional lead-free halide perovskite propylammonium silver bismuth bromide (PA₄AgBiBr₈) as the active matrix. The inherent ion migration feature of the perovskite shows great potential in emulating biological neurons. In addition, the deep conduction band minimum of PA₄AgBiBr₈ estimated from the ultra-violet photoelectron spectroscopy revealed efficient electron injection/transfer from the top copper (Cu) and indium tin oxide (ITO) counter electrode. The device Cu/PA₄AgBiBr₈/ITO exhibited volatile threshold switching behavior (off/on ratio ∼ 10⁴), which is the signature of DM. The DM device exhibited fast switching (∼140 μs) and reproducible endurance cycles (10³). The transient switching nature of the DM device could be hypothesized to the formation of thinner conducting filaments, which get ruptured inevitably due to high surface reflux. Because of the transient switching behavior, the DM mimicked the characteristics of biological nociceptors, showing sensitivity to external stimuli and vital features including threshold, lack of adaptation, relaxation and sensitization. Thus, it can be emphasized that two-dimensional PA₄AgBiBr₈ possesses great potential as the active material in artificial sensory and intelligence system.