Photomultiplication organic photodetectors featuring bias-switchable broadband/narrowband responses based on electron tunneling

Organic photodetectors (OPDs) have received considerable attention due to their advantages over traditional inorganic alternatives. Their attributes, including cost-effective processing, tunable bandgap capabilities, flexibility, and scalability, position them as strong candidates for the next generation of photodetection technology. In this study, we introduce photomultiplication-type organic photodetectors (PM-OPDs) utilizing non-fullerene acceptors (NFAs) with switchable functionalities. These OPDs can transition between narrowband and broadband detection modes depending on the applied bias magnitude. Additionally, the incorporation of NFAs extends the spectral response of the OPDs into the near-infrared range. In narrowband mode, the device demonstrates external quantum efficiencies exceeding 100% at two peak wavelengths of 410 nm and 900 nm under low biases of ±0.3 V. When the bias is increased beyond 0.5 V, the PM-OPD transitions to broadband detection mode, encompassing a wide spectral range from 300 nm to 1000 nm. This impressive dual-mode detection capability is achieved without the need for an external optical filter or a trans-impedance amplifier, thereby simplifying the device design and reducing overall instrumentation requirements for various applications. The ability to switch between narrowband and broadband modes offers significant advantages in fields such as facial recognition, health monitoring, 3D sensing, spectroscopic applications, and optical communication. This research highlights the potential of bias-switchable PM-OPDs based on NFAs for advancing the next generation of photodetection systems.