对体CdSe纳米晶体表面结构复杂性的洞察:与特定缺陷相关的非辐射激发状态过程的效率
Mersedeh Saniepay1, Chenjia Mi1, Zhihui Liu1
1Department of Chemistry, Michigan State University , East Lansing, Michigan 48824-1322, United States.
Journal of the American Chemical Society
|January 3, 2018
概括
化 (CdSe) 纳米晶体 (NC) 的表面缺陷限制了它们的能源应用. 这项研究揭示了具有不同被动性质的两个不同的表面位点,这对于理解和改善NC性能至关重要.
科学领域:
- 材料科学
- 纳米技术
- 物理化学
背景情况:
- II-VI半导体纳米晶体 (NC) 与CdSe一样,遭受非辐射重组,阻碍了能量转换应用.
- 表面缺陷是已知的罪祸首,但由于探测挑战,它们对NC激发状态的确切性质和影响尚不清楚.
研究的目的:
- 为了研究富含混合物CdSeNC的表面化学.
- 了解碳酸盐复合物 (CdX2) 在表面缺陷中所扮演的角色.
- 阐明表面位点异质性,配体结合和光发光衰减之间的关系.
主要方法:
- 使用1H核磁共振 (NMR) 和光发光谱.
- 通过N,N,N',N'-四甲基乙烯-1,2-二胺 (TMEDA) 研究了CdX2连体的位移.
- 开发了一种合双平衡模型来分析表面结合热力学.
主要成果:
- 在CdSeNC上确定了两个独立的表面位点,具有明显的CdX2结合亲缘关系.
- 证明空隙只在特定的表面部位引起显著的光发光灭.
- 量化了不同位点之间的热力学贡献 (体和体).
结论:
- 通过CdX2配体的表面被动化是异质的,特定的方面表现出不同的结合亲和力和非辐射重组效率.
- 了解这种表面异质性是控制光发光和改善CdSeNC在能源应用中的关键.
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