Ultrahigh-Responsivity Near-Infrared Printed Photodetectors Based on Megasonically Processed RuCl₃ Nanosheets

Electronic structure modification via intercalative electron-doping of α-RuCl₃, a two-dimensional (2D) transition metal halide, imparts unique optoelectronic properties such as near-infrared (NIR) absorption. While bulk-scale RuCl₃ nanosheet production has been established using conventional liquid phase exfoliation, printed devices compatible with scalable manufacturing remain unexplored. Here, we demonstrate fully aerosol-jet-printed (AJP) NIR photodetectors based on megasonically processed RuCl₃ nanosheets. The NIR photoresponse is enhanced by intercalation-based electron-doping in two stages: primary electrochemical intercalation of bulk RuCl₃ crystals with quaternary ammonium bromides followed by megasonic exfoliation and secondary intercalation with polyvinylpyrrolidone. The degree of doping is controlled by the starting size of the primary intercalant, as larger primary intercalants ultimately enable greater secondary intercalation and electron-doping. In this manner, the combination of two-step intercalative doping and megasonic processing results in fully printed photodetectors with NIR responsivity of 244 mA/W at 1550 nm, outperforming previous reports by more than an order of magnitude.