A Retina-Inspired Organic Iono-Optoelectronic Synapse.

Retina-inspired neuromorphic systems require seamless integration of light sensing and adaptive synaptic modulation, yet conventional materials fail to integrate ionic charge transport with optoelectronic signal processing. Organic iono-optoelectronic devices offer a promising solution by coupling the optoelectronic properties of conjugated polymers with ionic and electronic transport. Here, we present an organic iono-optoelectronic synapse enabled by a p-type mixed ionic-electronic conductor (OMIEC). The OMIEC material, gDPP-MeOT2, a donor-acceptor polymer comprising a thiophene-flanked diketopyrrolopyrrole acceptor and methoxy-bithiophene donor, serves simultaneously as a light absorber and an ion reservoir, enabling light-modulated mixed charge transport. Our iono-optoelectronic synapse exhibits broad-band light detection spanning the visible to near-infrared range and synaptic plasticity features central to learning processes of the human brain. These results suggest that OMIECs can unify light detection, logic operation, and energy-efficient information processing, paving the way for next generation biohybrid vision systems and bio-inspired neuromorphic electronics.