Synergistic Interface Engineering via Buffer Layer and UVO Treatment for High-Performance PbS Quantum Dot...

While PbS quantum dot (QD) photodetectors exhibit promising near-infrared (NIR) response, their performance is limited by interfacial defects and damage caused by ligand-exchange processes. This study introduces a dual-interface engineering strategy: (I) A solution-processable Poly-TPD buffer layer is inserted between the PbS-halide active layer and PbS-EDT hole transport layer to mitigate EDT/acetonitrile-induced interfacial damage and improve hole extraction; (II) A controlled UV-ozone treatment is applied to the PbS-EDT layer to enhance p-doping density and reduce defect states. The optimized device achieves a dark current density as low as 74 nA cm^{- 2} at -0.5 V, a responsivity of 0.42 A W^-1 (at 1350 nm illumination), and a specific detectivity (D*) of 2.1 × 10¹² Jones, placing it among the higher-performing solution-processed PbS CQD photodiodes operating in the 1.3-1.4 µm range. This work provides a scalable approach for developing high-performance solution-processed NIR photodetectors.