Solution-processed efficient organic upconversion device for direct NIR imaging

Abstract

Abstract Infrared upconversion devices (UCDs) enable NIR imaging without array and readout circuits, making them desirable for portable sensor, imaging and monitoring. However, the exorbitant cost and high operating voltages associated with vacuum-deposited materials, which are usually employed in high-performance UCDs, restrict their application in flexible systems. Here, we report a solution-processed upconversion device (s-UCD), which is composed of detector and emitter, with high conversion efficiency (11.9%) and low turn-on voltage (1.2 V) achieved by rigorous device structure design and interlayer engineering. We investigated the role of the electron blocking layer in s-UCDs, and a peak luminance of 5500 cd m-2 and a luminance on-off ratio of 95,000 were achieved. Our s-UCDs exhibit high resolution, microsecond response time and are compatible with flexible substrates. With the high-performance large-area s-UCDs, we further performed direct non-invasive transmission-based bioimaging applications with high quality of bioimaging. Owing to the solution-processed fabrication, it is believed that our s-UCD imaging system offers potential applications for portable low-cost non-invasive tissue analysis, disease diagnosis, and virtual reality.