Dipole Regulation Enables Efficient Near‐Infrared Perovskite Quantum Dots Photodetector

Abstract Conductive quantum dots (QDs) ink presents a promising platform for fabricating direct‐print photodetectors and wearable devices. Although great efforts regarding improving QDs ink with reduced defects density and colloidal dispersion, the carrier separation dynamic and interface mismatches during device operation are normally neglected. In this work, the surface dipole moment of the QDs is successfully regulated. Besides the surface passivation, it is found that the dipole moment can downward the valence band maximums, reducing the injection barrier and facilitating photogenerated carrier separation. With this strategy, the perovskite QDs ink was prepared and used in a near‐infrared photodetector for the first time. The device exhibits a detectivity of 5 × 10¹ 2 Jones and a fast response of 2.2 µs: this possesses one of the highest detectivities for QDs based photodiodes. Furthermore, this ink‐based photodetector is integrated into pulse detection systems, demonstrating its potential for health monitoring applications.