Abstract
Label‐free, real‐time, portable, and cost‐effective detection of nanoscale objects is central to early‐stage detection of fatal diseases, environmental monitoring, homeland security, and so on. Owing to their extremely large Q/volume and enhanced light–matter interaction, micro‐ and nanophotonic sensors are intensively studied and their performances are significantly improved. To date, single molecule, single virus, and single nanoparticle have been successfully monitored with microscopic and spectroscopic systems, e.g., high‐Q microcavities and plasmonic devices. However, the current technologies suffer from drawbacks such as instability to ambient vibration, long analyzing time, and high costs. Their widespread uses, especially in portable point‐of‐care devices, are strongly hindered. Herein, taking full advantages of methylammonium lead tri‐halide (MAPbX3) perovskite, the perovskite photodetectors with Si3N4 waveguides are integrated and their potential in on‐chip‐integrated optical sensors is demonstrated. With a simple laser diode, single nanoparticle with radius ≈70 nm is successfully gauged for the first time.
Lead halide perovskite based on‐chip‐integrated optical sensors are demonstrated here. Owing to the ability of MAPbI3 perovskite photodetector in detecting weak light, nanoscale objects with radius as small as ≈70–80 nm (size of typical Exosomes of cancers) are simply resolved by real‐time monitoring the changes of photocurrent.