Kamath Ananth, Schaller Richard D, Guyot-Sionnest Philippe
Department of Chemistry and the James Franck Institute, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States.
Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States.
J Am Chem Soc. 2023 May 17;145(19):10809-10816. doi: 10.1021/jacs.3c02190. Epub 2023 May 3.
Fluorophores emitting in the NIR-IIb wavelength range (1.5-1.7 μm) show great potential for bioimaging due to their large tissue penetration. However, current fluorophores suffer from poor emission with quantum yields ∼2% in aqueous solvents. In this work, we report the synthesis of HgSe/CdSe core/shell quantum dots (QDs) emitting at 1.7 μm through the interband transition. Growth of a thick shell led to a drastic increase in the photoluminescence quantum yield, with a value of 63% in nonpolar solvents. The quantum yields of our QDs and other reported QDs are explained well by a model of Forster resonance energy transfer to ligands and solvent molecules. The model predicts a quantum yield >12% when these HgSe/CdSe QDs are solubilized in water. Our work demonstrates the importance of a thick type-I shell to obtain bright emission in the NIR-IIb region.
在近红外IIb波长范围（1.5 - 1.7μm）发射荧光的荧光团由于其在组织中的穿透性强而在生物成像方面显示出巨大潜力。然而，目前的荧光团在水性溶剂中的发射较差，量子产率约为2%。在这项工作中，我们报道了通过带间跃迁发射1.7μm荧光的HgSe/CdSe核/壳量子点（QDs）的合成。厚壳的生长导致光致发光量子产率急剧增加，在非极性溶剂中的值为63%。我们的量子点和其他报道的量子点的量子产率通过福斯特共振能量转移到配体和溶剂分子的模型得到了很好的解释。该模型预测，当这些HgSe/CdSe量子点溶解在水中时，量子产率>12%。我们的工作证明了厚I型壳对于在近红外IIb区域获得明亮发射的重要性。
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