Regulating Charge Distribution to Achieve High‐Performance n‐Type Single‐Component Organic Neuromorphic Phototransistors

Organic optoelectronic devices are advancing toward miniaturization and integration, demanding high performance, low energy consumption, and simplified manufacturing. The development of single-component phototransistors is still in its early stages, particularly for high-performance n-type polymer semiconductors. Here, thieno[3,2-b]thiophene-3,6-dicarbonitrile (2CNTT) is developed and a cyano-mediated torsion-polarization synergy strategy is proposed to construct conjugated polymers via direct (hetero)arylation polycondensation. This structural modification promotes intramolecular decoupling and enhances intermolecular interactions, enabling intra-/interchain charge distribution to be regulated. N-type copolymers based on 2CNTT exhibited broad visible-light absorption range and small exciton binding energy, capable of stable exciton generation and stepwise dissociation. The PFIID2NTT-based single-component phototransistor showed stable unipolar electron mobility and strong photoresponse with light-current/dark-current ratio as high as 9.02 × 10⁴, and a paired-pulse facilitation index over 236% under visible light. The devices also operate at an ultra-low energy consumption (13.23 aJ), mimicking neural synapse behavior and enabling long-term memory functionality. The strategy optimizes charge distribution and exciton utilization in n-type polymer semiconductors, presenting a new paradigm for developing multifunctional organic optoelectronics.