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通过动态核极化增强的Se和Cd固态NMR光谱揭示Cd纳米晶体的表面结构

Yunhua Chen^1,2, Rick W Dorn^1,2, Michael P Hanrahan^1,2

¹U.S. Department of Energy Ames Laboratory, Ames, Iowa 50011, United States.

Journal of the American Chemical Society

|June 4, 2021

概括

动态核极化 (DNP) 固态NMR揭示了化 (CdSe) 纳米晶体的详细表面结构. 这种先进的技术确定了球形CdSe表面的特定原子排列,并证实了{100}个方面.

科学领域:

材料科学
纳米技术
固态化学

背景情况:

了解半导体纳米晶体的表面结构对于它们的应用至关重要.
混合化物 (CdSe) 含有碳酸联体的NC具有复杂的表面组成.
之前的方法缺乏详细描述NC表面的原子安排的分辨率.

研究的目的:

使用先进的NMR技术阐明混合物CdSeNC的详细表面结构.
确定表面原子的特定协调环境.
为了确定表面的立体测量和面向.

主要方法:

动态核极化 (DNP) 增强的固态核磁共振 (SSNMR) 光谱.
1D113Cd和77Se交叉极化神奇角旋转 (CPMAS) 核磁共振.
交叉极化魔术转角 (CP-MAT) 的实验.
2D同核和异核标尺相关性NMR实验 (Cd, Se, Se).
七十三个等级异核多重量子连贯性 (J-HMQC) 和J-解决的NMR实验.

主要成果:

显著的NMR信号分化了表面和大量的Cd和Se原子.
确定了Cd协调环境,包括CdSe₃O,CdSe₂和CdSeO₃.
确定CdSe₂O₂和SeCd₄的表面积.
证实球形CdSeNC主要暴露了{100}个方面.

结论:

用DNP增强的SSNMR提供了前所未有的CdSeNC表面结构细节.
球形CdSeNC的表面主要由{100}个方面组成.
使用的NMR方法广泛适用于其他主要组半导体纳米粒子.

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