Probing the Surface Structure of Semiconductor Nanoparticles by DNP SENS with Dielectric Support Materials
| العنوان: | Probing the Surface Structure of Semiconductor Nanoparticles by DNP SENS with Dielectric Support Materials |
|---|---|
| المؤلفون: | Jennifer L. Stein, Yunhua Chen, Michael P. Hanrahan, Aaron J. Rossini, Javier Vela, Brandi M. Cossairt, Marquix A. S. Adamson, Gregory F. Pach, Rafael Blome-Fernández, Nathan R. Neale |
| المصدر: | Journal of the American Chemical Society. 141:15532-15546 |
| بيانات النشر: | American Chemical Society (ACS), 2019. |
| سنة النشر: | 2019 |
| مصطلحات موضوعية: | Chemistry, Nanoparticle, General Chemistry, Nuclear magnetic resonance spectroscopy, Dielectric, Mesoporous silica, 010402 general chemistry, 01 natural sciences, Biochemistry, Catalysis, Homonuclear molecule, 0104 chemical sciences, Colloid and Surface Chemistry, Chemical engineering, Heteronuclear molecule, Polarization (electrochemistry), Two-dimensional nuclear magnetic resonance spectroscopy |
| الوصف: | Surface characterization is crucial for understanding how the atomic-level structure affects the chemical and photophysical properties of semiconducting nanoparticles (NPs). Solid-state nuclear magnetic resonance spectroscopy (NMR) is potentially a powerful technique for the characterization of the surface of NPs, but it is hindered by poor sensitivity. Dynamic nuclear polarization surface enhanced NMR spectroscopy (DNP SENS) has previously been demonstrated to enhance the sensitivity of surface-selective solid-state NMR experiments by 1-2 orders of magnitude. Established sample preparations for DNP SENS experiments on NPs require the dilution of the NPs on mesoporous silica. Using hexagonal boron nitride (h-BN) to disperse the NPs doubles DNP enhancements and absolute sensitivity in comparison to standard protocols with mesoporous silica. Alternatively, precipitating the NPs as powders, mixing them with h-BN, and then impregnating the powdered mixture with radical solution leads to further 4-fold sensitivity enhancements by increasing the concentration of NPs in the final sample. This modified procedure provides a factor of 9 improvement in NMR sensitivity in comparison to previously established DNP SENS procedures, enabling challenging homonuclear and heteronuclear 2D NMR experiments on CdS, Si, and Cd3P2 NPs. These experiments allow NMR signals from the surface, subsurface, and core sites to be observed and assigned. For example, we demonstrate the acquisition of DNP-enhanced 2D 113Cd-113Cd correlation NMR experiments on CdS NPs and natural isotropic abundance 2D 13C-29Si HETCOR of functionalized Si NPs. These experiments provide a critical understanding of NP surface structures. |
| تدمد: | 1520-5126 0002-7863 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::6fc52206526665c095493fa727228d66 https://doi.org/10.1021/jacs.9b05509 |
| حقوق: | OPEN |
| رقم الأكسشن: | edsair.doi.dedup.....6fc52206526665c095493fa727228d66 |
| قاعدة البيانات: | OpenAIRE |
Find this issue from the American Chemical Society | تدمد: | 15205126 00027863 |
|---|