Flexible OFET Photodetectors Enhanced by Embedded Metal–Insulator–Metal Structure

Flexible photodetectors represent a key enabling technology for next-generation wearable and biointegrated optoelectronic systems. Integrating plasmonic metal–insulator–metal (MIM) structures into flexible electronics is challenging due to the mechanical fragility of continuous metal layers. Here, we report a flexible organic field-effect transistor (OFET) photodetector enhanced by an embedded MIM architecture (Ag/P3HT/AuNPs). Unlike rigid periodic metallic structures, this design leverages the stochastic spatial distribution of Au nanoparticles (AuNPs) to maintain a stable magnetic resonance effect even under mechanical deformation. This unique structure property correlation resolves the conflict between optical enhancement and mechanical flexibility. Consequently, the optimized device achieves a high responsivity of 441 mA/W and a detectivity of 1.23 × 1011 Jones (under 10 μW/cm2 illumination at VG = 0 V, VDS = −40 V), representing 19-fold and 16-fold enhancements over pristine devices. Remarkably, the device retains ∼ 80% of its initial performance after 1000 bending cycles. This work provides a facile, lithography-free strategy for constructing high-performance, strain-tolerant flexible optoelectronics.