Organic optical sensor based on monolithic integration of organic electronic devices

A novel organic optical sensor that integrates a front organic light-emitting diode (OLED) and an organic photodiode (OPD) is demonstrated. The stripe-shaped cathode is used in the OLED components to create light signals, while the space between the stripe-shaped cathodes serves as the detection window for integrated OPD units. A MoO₃ (5 nm)/Ag (15 nm) bi-layer inter-electrode is interposed between the vertically stacked OLED and OPD units, serving simultaneously as the cathode for the front OLED and an anode for the upper OPD units in the sensor. In the integrated sensor, the emission of the OLED units is confined by the area of the opaque stripe-shaped cathodes, optimized to maximize the reflected light passing through the window space for detection by the OPD components. This can ensure high OLED emission output, increasing the signal/noise ratio. The design and fabrication flexibility of an integrated OLED/OPD device also has low cost benefits, and is light weight and ultra-thin, making it possible for application in wearable units, finger print identification, image sensors, smart light sources, and compact information systems.