High-Performance Photomultiplication-Type Organic Photodetectors Based on Single-Donor Dual-Acceptor Ternary Bulk Heterojunctions

In order to raise the performance of the photomultiplication-type organic photodetectors (PM-OPDs) based on P3HT:IEICO-4F, PC61BM was added into the P3HT/IEICO-4F blends and the PM-OPDs with the structure of ITO/PEDOT/PSS/P3HT/PC61BM/IEICO-4F(100:x:10–x, wt/wt/wt)/Al were prepared. The absorption and photoluminescence spectra of the active-layer films and the current–voltage characteristics of the devices were measured. The results showed that a wide spectral response of 450–980 nm is achieved in the devices, and the photoelectric performance of the PM-OPDs with x = 1, 2, and 3 is better than that of those with x = 0, and a maximum external quantum efficiency of 1353.4%, a specific detectivity of 7.87 × 1013 Jones, a photoresponsivity of 925.96 A/W, and a minimum noise equivalent power of 6.93 × 10–15 W/Hz1/2 are simultaneously got for the devices with x = 1 at −15 V bias and under 850 nm illumination. Such a fine performance can be due to the fact that adding PC61BM into P3HT/IEICO-4F blends produces new exciton dissociation interfaces and electron trap types in the active layer, and thus the exciton dissociation efficiency and the photogenerated electron capture rate of the devices are both heightened, and as a result, the photomultiplication induced by external hole tunneling is enhanced.