Zn-doping enhances the photoluminescence and stability of PbS quantum dots for in vivo high-resolution imaging in the NIR-II window


Lead sulfide (PbS) quantum dots (QDs) are important near infrared (NIR) luminescent materials with tunable and strong emission covering a broad NIR region. However, their optical properties are quite sensitive to air, water, and high temperature due to the surface oxidation, thus limiting their applications in optoelectronic devices and biological imaging. Herein, a cation-doping strategy is presented to make a series of high-quality Zn-doped PbS QDs with strong emission covering whole second near-infrared window (NIR-II, 1,000-1,700 nm). First-principle calculations confirmed that Zn dopants formed dopant states and decreased the recombination energy gap of host PbS. Notably, the Zn dopants significantly improved the quantum yield, photoluminescence lifetime and thermal stability of PbS QDs. Moreover, the PEGylated Zn-doped PbS QDs emitting in the NIR-llb window (1,500-1,700 nm) realized the noninvasive imaging of cerebral vascular of mouse with high resolution, being able to distinguish blood capillary. This material not only provides a new tool for deep tissue fluorescence imaging, but is also promising for the development of other NIR related devices.

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This work was supported by the National Natural Science Foundation of China (Nos. 21974104 and 21703221) and the National Postdoctoral Science Foundation of China (No. 2012T50663). We thank Prof. Yi Liu and Prof. Feng-Lei Jiang (Wuhan University) for their help with photoluminescence measurement and Shaobo Mo (Analysis and Testing Center of Wuhan University) for his help with the TEM experiment. We are grateful to the Supercomputing Center of University of Science and Technology of China for the computing resource.

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Correspondence to Mingxi Zhang.

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Shi, X., Chen, S., Luo, M. et al. Zn-doping enhances the photoluminescence and stability of PbS quantum dots for in vivo high-resolution imaging in the NIR-II window. Nano Res. (2020). https://doi.org/10.1007/s12274-020-2843-4

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  • quantum dots
  • doping
  • second near-infrared window (NIR-II window)
  • tunable emission
  • in vivo imaging