Tunable Full-Color Electroluminescence from All-Organic Optical Upconversion Devices by Near-Infrared Sensing

Full-color all-organic optical upconversion devices that can directly convert incident near-infrared (NIR) light into tunable visible light were developed by integrating an organic light-emitting diode (OLED) on an NIR-sensitizing organic photodetector. Thermally activated delayed fluorescence (TADF) emitters were utilized for the first time in the upconversion devices for achieving high electroluminescence (EL) efficiency in the OLED unit and high overall upconversion efficiency. The emission color of upconversion EL can be varied across the entire visible region ranging from blue to red and white by judicious selection of the incorporating TADF emitters. These all-organic optical upconversion devices have a great potential for low-cost, large-area, pixelless NIR imaging applications.