High‐Performance Self‐Powered Quantum Dot Infrared Photodetector with Azide Ion Solution Treated Electron Transport Layer

Abstract The demand for self‐powered photodetectors (PDs) capable of NIR detection without external power is growing with the advancement of NIR technologies such as LIDAR and object recognition. Lead sulfide quantum dot‐based photodetectors (PbS QPDs) excel in NIR detection; however, their self‐powered operation is hindered by carrier traps induced by surface defects and unfavorable band alignment in the zinc oxide nanoparticle (ZnO NP) electron‐transport layer (ETL). In this study, an effective azide‐ion (N 3 − ) treatment is introduced on a ZnO NP ETL to reduce the number of traps and improve the band alignment in a PbS QPD. The ZnO NP ETL treated with azide ions exhibited notable improvements in carrier lifetime and mobility as well as an enhanced internal electric field within the thin‐film heterojunction of the ZnO NPs and PbS QDs. The azide‐ion‐treated PbS QPD demonstrated a increase in short‐circuit current density upon NIR illumination, marking a responsivity of 0.45 A W −1 , specific detectivity of 4 × 10 11 Jones at 950 nm, response time of 8.2 µs, and linear dynamic range of 112 dB.