High-Performance PbSe Quantum Dots with Palmitoyl Chloride and Their Application to Short-Wavelength Infrared Photodetector Devices

Quantum dots (QDs), particularly those in the short-wavelength infrared (SWIR) range, have garnered significant attention for their unique optical and electrical properties resulting from 3D quantum confinement. Among the various chalcogenide-based QDs, lead chalcogenides, such as PbS and PbSe, are extensively studied for infrared photodetection applications. While PbSe QDs offer advantages over PbS, including a narrower bandgap and higher carrier mobility, they suffer from stability issues due to surface oxidation and particle aggregation. Conventional synthesis methods require additional post-synthesis treatments for surface passivation with halides, which complicates the process. In this work, a novel synthesis approach that incorporates palmitoyl chloride (PalCl) into the traditional PbSe QD synthesis is introduced, effectively passivating the surface with Cl⁻ ions during the synthesis process. This method not only enhances the optical performance by producing a sharp exciton peak and allowing precise tuning of the absorption spectrum from 1100 to 1900 nm but also significantly improves the stability of the QDs in solution. The resulting QDs are successfully integrated into SWIR photodetectors (PDs), demonstrating exceptional specific detectivity of 1.08 × 10¹² Jones at 1460 nm. This achievement draws great potential of the proposed synthetic method for advancing infrared optoelectronic devices.