Engineering Ag+ flux via PMMA incorporation for stable threshold switching and temporal neuromorphic processing in flexible SnO2 quantum dot memristors

In this work, flexible Ag/SnO2 quantum dots (QDs):PMMA (1:0, 1:0.5, 1:1, and 1:1.5)/ITO memristors were fabricated by blending SnO2 QDs and PMMA at different volume ratios. The polymer-assisted Ag+ migration engineering strategy enables effective regulation of conductive filament evolution, inducing a controllable transition from unstable nonvolatile resistive switching to highly stable threshold switching (TS). The Ag/SnO2 QDs:PMMA (1:1)/ITO device exhibits a switching window of ∼25, stable TS over 104 cycles, and excellent mechanical reliability after 104 bending cycles at a bending radius of 4 mm. The polymer matrix modulates Ag+ migration kinetics, facilitating the formation of uniformly distributed metastable. Benefiting from these characteristics, the Ag/SnO2 QDs:PMMA (1:1)/ITO device enables leaky integrate-and-fire and adaptive leaky integrate-and-fire neuron functions. Furthermore, the intrinsic volatile conductance relaxation enables time-dependent image feature extraction by dynamically modulating convolutional weights through Ag filament evolution. This work demonstrates that polymer-assisted Ag+ migration engineering provides an effective strategy for developing flexible volatile memristors toward compact neuromorphic computing hardware.