Nanoscale ternary chalcogenides have attracted increasing research interest due to their merits of tunable properties and diverse applications in energy and biomedical fields. In this article, silver indium sulfide quantum dots supported by glutathione and polyethyleneimine as dual-ligands have been synthesized through an environmentally friendly and reproducible aqueous method. An emission quantum yield up to 37.2% has been achieved by glutathione as co-ligand bearing electron-rich groups, much higher than that of polyethyleneimine coated quantum dots (4.97%). Both spectroscopic and structural characterizations demonstrate that the photoluminescence enhancement is attributed to change of surface properties by glutathione as co-ligand. Dynamic light scattering (DLS) results and thermogravimetric analysis (TGA) reveal that glutathione covers the QDs with a higher density on the nanocrystal surface than other co-ligands. Therefore, it can effectively passivate the surface trap centers, thus decreasing the non-radiative emission. Moreover, the resultant silver indium sulfide quantum dots present surprisingly long lifetime of 3.69 μs, excellent fluorescent stability and low cytotoxicity, which enables them to be ideal candidate for real-time bioimaging.

中文翻译：

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用于生物成像的强发光且长寿命的银铟硫化物量子点：深入了解共配体对增强光致发光的影响。

纳米级三级硫族化物因其具有可调性的优点以及在能源和生物医学领域的多种应用而吸引了越来越多的研究兴趣。在本文中，通过环境友好且可重现的水性方法合成了由谷胱甘肽和聚乙烯亚胺作为双配体负载的银铟硫量子点。谷胱甘肽作为带有电子富集基团的共配体，可实现高达37.2％的发射量子产率，远高于聚乙烯亚胺涂覆的量子点（4.97％）。光谱学和结构表征均表明，光致发光增强归因于谷胱甘肽作为共配体的表面性质的变化。动态光散射（DLS）结果和热重分析（TGA）表明，谷胱甘肽以比其他共配体更高的密度覆盖了纳米晶体表面的量子点。因此，它可以有效地钝化表面陷阱中心，从而减少非辐射发射。此外，所得的银铟硫醚量子点的寿命令人惊讶，为3.69μs，具有出色的荧光稳定性和低细胞毒性，这使其成为实时生物成像的理想候选者。