Bias-Switchable Dual-Mode Organic–Inorganic Composite Photodetector with Tunable Spectral Response

The present article introduces a dual-mode photodetector based on PDPP3T:PC₆₁BM/PEDOT:PSS/ZnO, featuring switchable bias and a selectable light response. This design addresses the limitation of traditional photodetectors, which typically exhibit a narrow wavelength response range. By controlling the bias polarity, incident light of different wavelengths can be selectively detected in a single device. Under forward bias, the photodetector operates in a narrowband ultraviolet detection mode with a peak responsivity of 90.15 mA/W. Conversely, under reverse bias, it exhibits broadband detection from ultraviolet to near-infrared with an enhanced peak responsivity of 98.57 mA/W. The dual-mode response is generated by the combined action of the ZnO layer that absorbs ultraviolet light, the organic bulk heterojunction layer that absorbs light from ultraviolet to near-infrared, and the electron blocking layer PEDOT:PSS. This study presents a dual-mode photodetector with selective spectral response, offering potential applications in IoT, security sensing, and biological imaging.