Abstract
As demand for sustainable and biocompatible technologies grows, low-toxicity mid-infrared materials, such as silver chalcogenides, have attracted significant interest. Herein, we report mid-wavelength infrared tunable Ag2Te colloidal quantum dots through a post-growth method starting from short-wavelength infrared Ag2Te colloidal quantum dots. Using the synthesized Ag2Te colloidal quantum dots, we successfully fabricate a photodetector covering the full mid-wavelength infrared spectral range (3–5 μm) with an onset wavelength extending to 6.9 μm. At 78 K, the photodetectors exhibit a photoresponse time of 230 ns (rise) and 576 ns (fall). Responsivity varies from 1.9 × 10-3 A W−1 at 0.02 V to 1.1 A W−1 at 0.5 V, depending on the applied bias, and the specific detectivity of the device is 1.2 × 109 Jones at 0.02 V. The measured noise-equivalent temperature difference of 0.3 K enables us to reliably distinguish temperature variations between 37 °C and 40 °C, directly enabling the diagnosis of fever-level body temperatures.
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All data supporting the findings of this study are available within the paper and its Supplementary Information. Additional experimental data available from the corresponding author upon request.
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Acknowledgments
This research was supported by the Basic Science Research Program (NR059609 and NR068167) (K.S.J.). This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (RS-2025-25437404 and RS-2024-00407943) (S.Y.E. and H.S).
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S.Y.E. developed Ag2Te QD synthesis methods. J.H.L. carried out the temperature-dependent infrared photoluminescence and photocurrent spectroscopy measurement. S.Y.E. and J.H.L. infrared photodetection measurements and analysis. S.S. assisted in synthesizing the QD. H.S. assisted in infrared photodetection. S.Y.E., J.H.L., and K.S.J. wrote the manuscript with contributions from all co-authors, and K.S.J. supervised the project. All authors contributed to the discussion of the experimental results and the manuscript.
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Eom, S.Y., Lee, J.H., Song, H. et al. Non-toxic silver telluride colloidal quantum dot mid-infrared photodetector. Nat Commun (2026). https://doi.org/10.1038/s41467-026-71374-3
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DOI: https://doi.org/10.1038/s41467-026-71374-3
