Selective Photodetection at Specific Wavelengths in Filterless Single-Channel Field-Effect Transistors

Photodetectors are optoelectronic devices that output an electric signal when illuminated, with a wide range of uses in modern technologies from the fields of biomedical imaging to communications. However, further improving the sensitivity and functionality of these devices to achieve even broader applications would require further development of devices with selective detection capability over wide ranges of wavelengths. In this study, we present a novel photodetector capable of multiwavelength visible light detection using a blend of organic semiconductors and inorganic perovskites as active material. In this photofield-effect transistor (photoFET), the photogating effect of CsPbBr₃ nanocrystals upon illumination below 520 nm triggers a large shift in threshold voltage while illumination over 600 nm results in an increase in current without threshold voltage shift. As a result, the device exhibits the capability to discriminate red and blue light, while being sensitive to the intensity of incident light within the visible spectrum. This innovative device opens the door to the development of single photodetector devices capable of recognizing multiple wavelengths and shows strong promise for increased photosensitivity due to the lack of power losses from filters. Furthermore, the combination of transistor operation and detection functions has strong promise for the development of reconfigurable and neuromorphic circuits.