Luminescent Quantum Dots Stabilized by N-Heterocyclic Carbene Polymer Ligands
Luminescent Quantum Dots Stabilized by N-Heterocyclic Carbene Polymer Ligands
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DOI：
10.1021/jacs.0c10592
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发表时间：
2021-01-15
影响因子：
15
通讯作者：
Mattoussi, Hedi
中科院分区：
文献类型：
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作者：
Du, Liang;Nosratabad, Neda Arabzadeh;Mattoussi, Hedi
我们测试了N-杂环卡宾（NHC）修饰的配体在亲水介质中配位和稳定发光CdSe-ZnS核-壳量子点（QD）分散体的能力。特别是，我们探讨了配体结构和配位数对涂层亲和力的影响。我们发现这样的NHC基配体迅速配位到量子点上（需要类似于5-10分钟的反应时间），这反映了NHC基团的软刘易斯碱性质，其具有两个电子共享能力。通过H-1 NMR光谱验证了疏水帽的去除和纳米晶体上卡宾驱动配位的促进，而C-13 NMR用于鉴定卡宾-Zn络合物的形成。新涂覆的QD分散体在广泛的条件下表现出很大的长期胶体稳定性。此外，我们发现，到量子点表面的协调影响的纳米晶体的光学和光谱性质。这些包括吸收和荧光光谱的尺寸依赖性红移以及当样品在白色光暴露下储存时与在黑暗中储存的样品相比所测量的荧光强度的显著增加。
We have tested the ability of N-heterocyclic carbene (NHC)-modified ligands to coordinate and stabilize luminescent CdSe-ZnS core-shell quantum dot (QD) dispersions in hydrophilic media. In particular, we probed the effects of ligand structure and coordination number on the coating affinity to the nanocrystals. We find that such NHC-based ligands rapidly coordinate onto the QDs (requiring similar to 5-10 min of reaction time), which reflects the soft Lewis base nature of the NHC groups, with its two electrons sharing capacity. Removal of the hydrophobic cap and promotion of carbenedriven coordination on the nanocrystals have been verified by H-1 NMR spectroscopy, while C-13 NMR was used to identify the formation of carbene-Zn complexes. The newly coated QD dispersions exhibit great long-term colloidal stability over a wide range of conditions. Additionally, we find that coordination onto the QD surfaces affects the optical and spectroscopic properties of the nanocrystals. These include a size-dependent red-shift of the absorption and fluorescence spectra and a pronounced increase in the measured fluorescence intensity when the samples are stored under white light exposure compared to those stored in the dark.