Solution-Based Integration of Vertically Stacked Organic Photodetectors Toward Easy-To-Fabricate Filterless Multi-Color Light Sensors

摘要

Solution-processed, color-selective organic photodetectors are uniquelypositioned to deliver high-performance, low-cost, multicolor light sensors/imagers beyond the limitations of conventional, color-filter-based technologies.To realize such potential, however, a prominent challenge has beenthe solution-based, monolithic integration of vertically stacked organicphotodetectors, which would enable multicolor sensing with optimum lightcollection while benefiting from the scalability, cost, and sustainability edgesof solution-based manufacturing. To tackle this challenge, this paper demonstrates,for the first time, the monolithic integration of vertically stackedsolution-processed organic photodetectors for independent, multicolor lightsensing within the same pixel area. The solvent orthogonality challenge istackled by selecting polymer-based photoactive layers and an insulatingpolymeric spacer-for independent biasing and photocurrent readout—withcompatible processing conditions. Based on the suitable characteristics ofblue- and green-sensitive standalone devices, the vertically stacked, monolithicdevice architecture is optimized by also incorporating semitransparentelectrodes for photons to reach deep into the stack. The resultant devicearchitecture enables efficient blue- and green-selective photodetection withstate-of-the-art linearity, alongside speed of response adequate for realworldapplications. Based on its solution-processability and modularity,this approach paves the way for the facile, solution-based fabrication oforganic imagers covering multiple spectral regions with high sensitivity andresolution.