摘要： Flexible and lightweight photomultiplication-type organic photodetectors (PM-OPDs) have attracted wide attention for their broad application prospects, especially in the field of wearable electronic products. However, the common used indium tin oxide (ITO) conductive anode is not conducive to realize high-performance flexible PM-OPD due to its rigidity and fragility. Here, on the flexible polyethylene terephthalate (PET) substrate, we successfully fabricate highly sensitive poly 3-hexylthiophene:phenyl-C70-butyric acid methyl ester (P3HT:PC70BM, 100:1) based PM-OPDs using ultra-thin silver films as the transparent anode. Specifically, a 1 nm thick MoO3 layer is utilized as the wetting layer for facilitating the silver film percolation, and a 2 nm thick MoO3 layer, as the hole transport layer, is coated on top of the ultra-thin silver film before coating the P3HT:PC70BM film. The as-prepared flexible PM-OPDs based on the ultra-thin silver film exhibit the optimal external quantum efficiency (EQE) and responsivity (R) of 1.3×105 % and 388.4 A/W, respectively, under -15 V bias, which are 1.98 times and 2.15 times greater than those of the ITO anode based device. More importantly, the device has good flexibility with the EQE maintaining 70.6% of its initial value after 10 times of bending, and 51.4% of its initial value after 1000 times of bending. This work paves the way for developing flexible PM-OPDs as well as other flexible optoelectronic devices.