Colloidal InSb Quantum Dots Mid-Wave Infrared Photoconductive Detectors via One-Step Strong Acid Surface Treatment Strategy

Colloidal InSb quantum dots (QDs) hold significant promise in infrared photodetection. However, the current InSb QDs suffer from poor carrier mobility and limited spectral response (<1.8 μm) due to complex surface structure and high sensitivity to hydrolysis and oxidation. Here, we demonstrate one-step strong acid surface treatment strategy to simultaneously replace native insulating ligands and eliminate surface indium oxide. This dual-functional strategy achieves efficient surface passivation and enhances charge carrier transport, enabling InSb QDs films to exhibit an unprecedented hole mobility of 1.4 cm² V^-1 s^-1. Notably, we report the first realization of a broadband InSb QDs infrared photoconductive detector with spectral sensitivity extending beyond 3 μm at room temperature. The device exhibits a specific detectivity of 4.7 × 10⁷ Jones at 3.0 μm, representing the longest-wavelength interband photodetection based on lead/mercury-free QDs reported to date. This work manifests an important step toward room-temperature operable and heavy-metal-free QDs based mid-wave infrared photodetectors.