• • Record-high specific detectivity of ~4×10^13 Jones at zero bias, surpassing all BHJ-type self-powered OPDs, enabling low-light detection for water quality monitoring.
• • Thermal stability: negligible performance degradation after >800 h at 85°C, ensuring long-term operational reliability in industrial settings.
• • First systematic examination of solution aggregation in all-polymer OPD blends via small-angle neutron scattering and freeze-dried imaging, linking molecular entanglement to film morphology.
• • Broad spectral response enables dual application in water quality monitoring and biosensing, expanding market reach for low-cost polythiophene-based photodetectors.