Large-Area, Semitransparent, and Flexible All-Polymer Photodetectors

Photodetectors, converting optical signals from specific wavelengths to electrical signals, have many applications on photoimaging, optical communication, and environmental monitoring. Solution-processed organic photodetectors (OPDs) based on organic materials emerge promise especially for wearable electronics and smart buildings. In this work, new all-polymer photodetectors (all-PPDs) are developed based on bulk-heterojunction active layers which incorporate a donor polymer and an acceptor polymer. The inverted all-PPDs exhibit outstanding external quantum efficiency over 70%, low dark current density (J _d) of 1.1 × 10⁻⁸ A cm⁻², and high detectivity (D*) over 3.0 × 10¹² Jones with planar response over the entire visible range. It is one of the best-performing all-PPDs reported so far and is also comparable with many organic and inorganic photodetectors. By using lamination technique, large-area, semitransparent, flexible, and “fully” polymeric photodetectors are successfully fabricated for the first time, with D* over 10¹¹ Jones for double-side light detection. The results highlight the great potential for producing high-performance all-PPDs by taking advantages of various device architecture and solution-processing techniques.