Interfacial coupling-modulated ultraviolet photoresponse in WS₂/R6G hybrid structure with synapse-like...

Hybrid structures integrating two-dimensional semiconductors with organic molecules offer an effective platform for tuning interfacial carrier dynamics and optoelectronic functionality. Here, we report a WS₂/Rhodamine 6G (R6G) hybrid photodevice based on mechanically exfoliated monolayer WS₂ modified with R6G molecules. Under 375 nm illumination, the hybrid device exhibits a significantly enhanced ultraviolet photoresponse relative to pristine WS₂, with a responsivity of up to 2.1 A/W and a detectivity approaching 1.0 × 10¹² Jones. The device also shows clear synapse-like photoresponse characteristics, including excitatory postsynaptic current, pulse-number-dependent response, and frequency-dependent plasticity. Spectroscopic studies indicate that R6G modification substantially alters the exciton and carrier relaxation pathways of WS₂. Time-resolved measurements reveal that R6G modification alters the exciton relaxation process in WS₂, indicating interfacial carrier transfer from WS₂ to R6G. This interfacial process contributes to the enhanced photodetection performance and enables the synapse-like photoresponse of the hybrid device.