Dual-mode organic photodetectors enabled by adopting dual-interface carrier traps

Organic photodetectors (OPDs) have garnered significant attention due to their potential applications in both civil and military fields. Among them, bias-switchable dual-mode OPDs, which have recently been developed, show practical application promise for capacities to deliver amplified electric signals under weak light by working in a photomultiplication (PM) mode and to avoid high power consumption under strong light by choosing the photovoltaic (PV) mode. However, further development is needed in the device preparation methodology. In this study, we achieved dual-mode OPDs by adopting the structural innovation involving dual-interface carrier traps, i.e., oxygen defects in the ZnO interface layer and structural defects at the interfaces of the active layer and interface layer. The resulting dual-mode device with dual traps demonstrated an external quantum efficiency of 2509% at +2 V bias, representing an increase of 18.39% and 774.22% as compared to single-trap counterparts. Additionally, the specific detectivity reached 4.55 × 10¹¹ Jones and 6.22 × 10¹¹ Jones in PV and PM modes, respectively. This research presents a general strategy for achieving dual-mode OPDs that may meet the requirements of next-generation detection systems.