Confinement at Defect Sites Dissociates Ionic‐Liquid Pairs for Brain‐Like Organic Computing

ABSTRACT Organic electrochemical transistors (OECTs) have attracted significant attention as devices for emulating brain‐like information processing. However, their practical implementation is hindered by the limited ion modulation diversity at the active layer–electrolyte interface. To overcome this limitation, we introduce a metal–organic framework (MOF) as a selective ion‐conducting layer to modulate ion‐pair dissociation. The MOF layer is based on benzoic acid‐modified MIL‐125‐NH ₂ (BA‐MOF), which provides active sites that promote the efficient incorporation of ionic liquid ([EMIM][TFSI]) through intentional defect sites. The defective, highly porous architecture of BA‐MOF possesses open‐metal sites to tightly bound the ionic liquid. This integration suppresses ion diffusion through BA‐MOF, enhancing mobility and overall OECT performance. The effectiveness of this strategy is further demonstrated by MNIST pattern recognition simulations, achieving a maximum accuracy of 94.72%, which is close to the ideal benchmark of 95.22%. This observation is supported by density functional theory (DFT) calculations, which revealed that the confinement of [EMIM][TFSI] ion pairs within BA‐MOF reduces the ion‐pair dissociation energy, thereby leading to an increased concentration of free anions. These findings highlight that defect‐sites of MOF not only facilitate ionic‐liquid dissociation but also enable and stable synaptic responses, providing a promising strategy for high‐performance brain‐inspired organic computing.