Bilayer Interfacial Engineering Enabling Highly Sensitive Organic Photomultiplication Photodetector Across to Short‐Wave Infrared via Charge Transfer

ABSTRACT Highly sensitive organic photomultiplication photodetectors (PM‐OPDs) have important applications in the fields of communications, medicine, and environment. However, the prevalent use of acidity poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT: PSS) hole transport layer (HTL) in PM‐OPDs yields undesirable interfacial defects, resulting in the compromise of device performances. To avoid this, the bilayer interfacial engineering is introduced by incorporating an atomically‐thick Al 2 O 3 interlayer with MoO 3 HTL. It reveals that engineering the bilayer is crucial for the high‐quality MoO 3 HTL and adjusts Ohmic contact to Schottky contact near anode, which facilitates the suppressed dark current and maximized photocurrent of the device. Besides, the device exhibits the photoresponse to short‐wave infrared by P3HT:Y6 complex, because of the intermolecular charge transfer transition at the interface of P3HT and Y6. The results show that the bilayer‐PM‐OPDs manifest the high external quantum efficiency and responsivity of 5.94 × 10 3 % and 57 A/W at 1200 nm, superior to the MoO 3 control device (19.3%, 0.19 A/W, respectively). Simultaneously, the proposed device exhibits the detectivity of 1.28 × 10 13 Jones at 1200 nm and a broad dynamic range of 105 and 45 dB at 850 and 1310 nm. This work opens new horizons for high‐performance SWIR PM‐OPDs in various applications.