通过DNP SENS使用介电支材料探测半导体纳米粒子的表面结构
Michael P Hanrahan1,2, Yunhua Chen1,2, Rafael Blome-Fernández1
1Iowa State University , Department of Chemistry , Ames , Iowa 50011 , United States.
Journal of the American Chemical Society
|August 29, 2019
概括
使用六角化物 (h-BN) 的新方法显著提高了纳米粒子固态核磁共振 (NMR) 光谱的灵敏度. 这一进步使半导体纳米粒子的详细表面特征成为可能.
科学领域:
- 材料科学
- 纳米技术
- 光谱学
背景情况:
- 表面特征对于理解纳米粒子 (NP) 属性至关重要.
- 固态核磁共振 (NMR) 光谱提供了表面洞察力,但敏感性较低.
- 动态核极化表面增强NMR光谱 (DNP SENS) 提高了灵敏度,但需要对NP进行优化样本准备.
研究的目的:
- 在半导体纳米粒子上为DNP SENS开发改进的样品制备方法.
- 提高NP表面选择性NMR分析的灵敏度和范围.
- 能够详细确定各种NP的原子层面结构.
主要方法:
- 在DNP SENS中使用六角化物 (h-BN) 作为NP分散剂.
- 开发了一种粉末沉和浸方法,用于在DNP SENS样本中提高NP度.
- 使用DNP SENS对CdS,Si和Cd3P2NP进行同核和异核二维核磁共振实验.
主要成果:
- 与半孔相比,在h-BN中分散NP使得DNP增强率和绝对灵敏度增加了一倍.
- 修改后的粉末制备方法使灵敏度增加了4倍.
- 与之前的DNP SENS协议相比,NMR灵敏度总体提高了9倍.
- 成功获得了CdS和SiNP的DNP增强的2DNMR相关谱,分配了表面,地下和核心位置.
结论:
- 六角性化物 (h-BN) 是NP的DNP SENS的优质矩阵,与中等孔相比.
- 优化的样本制备显著提高了NMR的灵敏度,使得先进的二维NMR实验成为可能.
- 这种增强的DNP SENS方法为半导体纳米粒子的原子层面结构提供了关键的见解.
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