Arresting Ion Migration from The Etl Increases Stability in Infrared Light Detectors Based on Iii-V Colloidal Quantum Dots.

III-V colloidal quantum dots (CQDs) are of interest in infrared photodetection, and recent developments in CQDs synthesis and surface engineering have improved performance. Here we investigated photodetector stability, finding that the diffusion of zinc ions from charge transport layers (CTLs) into the CQDs active layer increases trap density therein, leading to rapid and irreversible performance loss during operation. In an effort to prevent this, we introduced organic blocking layers between the CQDs and ZnO layers; but these negatively impacted device performance. We then inverted the device, allowing us to use a C60:BCP top ETL for good morphology and process compatibility, and selecting NiOX as the bottom HTL. The first round of NiOX-based devices showed efficient light response but suffered from high leakage current and a low open-circuit voltage (Voc) due to pinholes. We introduced poly[bis(4-phenyl) (2,4,6-trimethylphenyl)amine] (PTAA) with NiOX NC to form a hybrid HTL, an addition that reduced pinhole formation, interfacial trap density, and bimolecular recombination, enhancing carrier harvesting. The photodetectors achieve 53% EQE at 970 nm at 1 V applied bias, and they maintain 95% of initial performance after 19 hours of continuous illuminated operation. The photodetectors retain over 80% of performance after 80 days of shelf storage. This article is protected by copyright. All rights reserved.