Vision System Utilizing Large-Area Organic Single Crystals for Sensory Applications
Organic field-effect transistor (OFET)-based optoelectronic synapses are pivotal for neuromorphic vision, yet polycrystalline/amorphous films suffer from grain-boundary carrier scattering and threshold instability, limiting spatiotemporal fidelity. This work employs large-area C8-BTBT single crystals to fabricate a low-voltage (1 V) optoelectronic synaptic array with a coefficient of variation of 8% in synaptic weight modulation. The grain-boundary-free structure mitigates interfacial defects, ensuring device-to-device uniformity. The array emulates human visual processing under distinct cognitive states: dispersed-attention mode (V_GS = 0.5 V) yields rapid response and short-term plasticity, while focused-attention mode (V_GS = 1.5 V) enables noise suppression and long-term potentiation via polarity-dependent carrier trapping. At 9.6 μW cm⁻² illumination, the device replicates essential synaptic functions, including learning and memory. Pattern recognition tests with six grayscale intensities demonstrate that the concentration state enhances photoresponse sensitivity and contrast discrimination, resolving fine details such as speckle patterns on bird plumage, whereas the moderate attention state fails to resolve such features. This platform advances hardware-level perception-computation integration for biomimetic vision chips, offering a pathway to energy-efficient, context-aware neuromorphic systems.