Self-Polarized Organic Ferroelectric Interfacial Materials for Highly Sensitive Near-Infrared Organic Photodiodes

Interfacial engineering plays a crucial role in charge transport and is widely employed to improve the performance of semiconductor devices. As one of the unique interfacial materials, organic ferroelectric materials can optimize device performance by self-polarization. Hereby, an attempt is made using poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) to fabricate highly sensitive near-infrared organic photodiodes (NIR OPDs). In this strategy, P(VDF-TrFE) can suppress the undesirable charge injection while simultaneously improving the transport of dissociated charge carriers from the photoactive layer by modifying surfaces and creating an additional built-in electric field (V_bi). As a result, it can obtain a superior performance with a low dark current density (J_d) of 7.6 × 10^-9 A cm^-2, a high responsivity (R) of 0.538 A W^-1and an impressive high specific detectivity of 1.1 × 10¹³ Jones at 930 nm under -1 V reverse bias, which exceeds most of the NIR OPDs reported in this field.