All-Solution-Processed Metal Oxide/Chalcogenide Hybrid Full-Color Phototransistors with Multistacked Functional Layers and Composition-Gradient Heterointerface

For the development of cost-effective, ultrasensitive, fast dynamic, and full-color photodetection platforms, an all-solution-processed metal oxide/chalcogenide semiconductor hybrid-structure-based visible-light phototransistor with (i) multistacked functional materials, (ii) a chemically stable solution-based construction, and (iii) defect-suppressed composition-gradient heterointerfaces is proposed. Herein, the functional multistacked structure (a-ZTO/cc-CdS/a-ZTO) consists of high-mobility amorphous zinc tin oxide (ZTO) (a-ZTO bottom), a high-efficiency coarsened crystalline CdS (cc-CdS) visible-light absorber, and defective surface passivation a-ZTO (top) to boost photosensitivity via efficient generation/transport and spontaneous separation/confinement of photocarriers. Chemically stable solution-based multistacking is achieved via careful choice of chemically durable oxide and chalcogenide semiconductors (Sn-eqi ZTO and CdS). The composition-gradient heterointerfaces formed near ZTO/CdS and CdS/ZTO junctions via thermally activated healing processes provide instantaneous photoresponse and full-color sensing performance. Finally, the all-solution-processed a-ZTO/cc-CdS/a-ZTO hybrid phototransistor achieves repeatable/reproducible real-time full-color detection with high photosensitivity, fast phototransient speeds, and no persistent photocurrent behavior under dynamic stimulus using primary colors. It is believed that the all-solution processed oxide/chalcogenide hybrid phototransistor with multistacked functional materials and composition-gradient heterointerfaces will facilitate the development of cost-efficient, ultrasensitive, fast dynamic, and full-color visible-light detection system.