Ultrahigh-Sensitive Broadband Phototransistor Using PM6:Y6 Bulk-Heterojunction

Abstract

Bio-imaging technology has a considerable advantage in monitoring the condition of our body noninvasively and spatially. However, conventional imaging devices using Si-, InGaAs-photodiode still have a rigid form factor, limiting real-time data acquisition with high pixel resolution from the human body. Recently, to overcome the aforementioned problems, the hybrid configuration combined various photosensitive materials with a metal-oxide semiconductor thin-film transistor (TFT) has been introduced. In this study, we present a PM6:Y6 bulk-heterojunction (BHJ)/indium–gallium–zinc–oxide (IGZO) hybrid phototransistor with an ultrahigh gain at a broad spectrum (450–1050 nm). From the photoresponse characteristics under various blending ratios, we observed that Y6 content over 50% enables the increase of the photocurrent and fast decay process at the same time. The optimized device achieved a specific detectivity (D*) of 5.2  1016 Jones at 750 nm wavelength, which can detect an ultra-weak light intensity of 1.03 nW cm-2. Our hybrid phototransistor consisting of PM6:Y6 and IGZO is expected to be a skin-compatible, flexible, and highly sensitive bio-imaging device.