Ternary Compensation Enables High-sensitive Efficient Upconversion Device for NIR Visualization

Beyond the crystalline photodiodes for infrared visualization, with the limitation of opacity and complex lithographic processes, organic upconversion device (UCD) have emerged as a potential alternative. In this research, a ternary compensation strategy is implemented in a non-fullerene-based active layer to reduce the dark current of the detector and enhance its detection performance, which enables high-sensitive efficient upconversion device for near-infrared light (NIR) visualization. The device achieves an infrared-to-visible upconversion efficiency of 16.68% when resolving the 980 nm infrared signal at a power density of 0.4 mW cm⁻². In addition, by replacing the semitransparent matrix electrodes, a large-area (12.25 cm²) is further fabricated, lightweight (6.5 g containing encapsulation), pixel-less (equivalent resolution 1270 ppi), and semitransparent (AVT ≈40%) UCD with microsecond response time. The fabricated UCD is demonstrated in pixel-less active infrared naked-eye visualization and infrared counter-surveillance, fostering the advancement of infrared visualization technology.