Hardness of PbS nanocrystal-based photoconductor to x-ray irradiation
Abstract
Colloidal lead sulfide (PbS) nanocrystals (NCs) are emerging as cost-effective and solution-processable materials for infrared (IR) detection. Their use in a space environment is conditioned by their radiation tolerance. This study investigates the intrinsic robustness of PbS NC-based photoconductive devices to high-dose x-ray irradiation (up to 1.6 Grad [PbS]), far above the requirements for deep-space operation. PbS NC films exhibit gradual performance degradation without abrupt thresholds, attributed to their polycrystalline nature, which localizes defects and mitigates long-range lattice disruption. Optoelectronic measurements reveal a drop in both the dark and illuminated response, yet the signal-to-noise ratio improves due to the faster decay of the dark current. Spectroscopic analyses (x-ray photoemission spectroscopy/hard x-ray photoemission spectroscopy) confirm that the conductivity change can be attributed to x-ray-induced oxidation, which affects both Pb and S, forming sulfate and lead hydroxide phases that propagate throughout the NC volume. This oxidation reduces the effective NC size, blue-shifting the excitonic peak. Despite this, PbS NCs exhibit exceptional radiation hardness, comparable to that of radiation-hardened CMOS devices. These findings position PbS NCs as viable candidates for spaceborne IR detection, especially in oxygen-free environments where oxidation is naturally limited.
Read the paper
Related studies
- The potential and limitations of neutrons, electrons and X-rays for atomic resolution microscopy of unstained biological molecules
- X-ray-Computed Tomography Contrast Agents
- Reactivity of Surface Species in Heterogeneous Catalysts Probed by In Situ X-ray Absorption Techniques
- Single-crystal X-ray diffraction studies on structural transformations of porous coordination polymers
- Investigation of solid/vapor interfaces using ambient pressure X-ray photoelectron spectroscopy
- Resonant X-Ray Scattering Studies of Charge Order in Cuprates
Go deeper in Evidence Hub
Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.