Fingerprint Recognition Matrix Based on Photomultiplication-Type Organic Photodetectors with a Signal-to-Noise Ratio...

Large-area and highly sensitive image sensors are vital for undercell fingerprint recognition technology. The photomultiplication-type organic photodetector (PM-OPD) is one of the alternative choices due to its special active layers with the ratio of donor to acceptor by weight of about 100:3 for achieving single charge carrier transport channels, resulting in relatively low dark current density and high external quantum efficiency under low bias. The optimal PM-OPDs exhibit a maximal 2.1 × 10¹² Jones specific detectivity at 610 nm under -6 V bias and a high signal-to-noise ratio of 51,400 at -5.2 V bias. Solution-processed PM-OPDs were prepared onto the top of a polycrystalline-silicon thin-film transistor readout circuit, and image sensors were successfully realized with 338 pixels resolution per inch. The electrical and optical properties of the fingerprint sensor were investigated, and high-quality fingerprint images were obtained.