Interface Engineering Enables High-performance PbS Colloidal Quantum Dots Imager via Tungsten Oxide Hydrophilic Layer

PbS colloidal quantum dots (CQDs) offer solution-processability, tunable bandgap, and monolithic integration with complementary metal oxide semiconductor (CMOS) readout circuit, making them highly adaptable for advanced infrared detection. However, optimizing interfacial quality remains critical for achieving high performance of PbS CQDs imager. In particular, the hydrophobicity of the C 60 sacrificial layer disrupts the atomic layer deposition of SnO 2 , leading to poor film uniformity, low density, and increased interfacial defects. To address this, a hydrophilic WO x interlayer atop C 60 is introduced, significantly improving SnO 2 deposition, reducing interfacial defects, and suppressing dark current density to 287 nA/cm 2 at −0.5 V. This strategy also mitigates halide ion migration from halide-passivated CQDs surface to SnO 2 layer, enhancing device stability. Consequently, this CQDs photodiodes achieve a high specific detectivity of 2.47 × 10 12 cm·Hz 1/2 ·W −1 . Furthermore, the monolithically integrated CQDs imager with CMOS readout circuit demonstrates advanced capabilities for material differentiation and penetration imaging.