光Cu+-和Ag+-化CdSe纳米晶体中的中间隙状态和正常与反向结合
Heidi D Nelson1, Stijn O M Hinterding1, Rachel Fainblat1
1Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States.
Journal of the American Chemical Society
|April 20, 2017
概括
铜和银配半导体纳米晶体 (NC) 的中间光显得相似,但它们的电子结构不同. 孔在Cu-doped NCs中的铜上定位,但在Ag-doped NCs中的联体上,使光谱与电离能调和.
科学领域:
- 材料科学
- 固态物理
- 量子化学
背景情况:
- 化半导体纳米晶体 (NC) 中的中隙发光涉及电子孔重组.
- 用铜 (Cu+) 合的NC显示出来自非定位电子和Cu定位孔的发光.
- 银 (Ag+) 合的NC表现出相似的发光,这是由于不同电离能量的悖论.
研究的目的:
- 尽管有不同的电离能,但在Cu+和Ag+合的半导体NC中显然存在相似发光的悖论.
- 阐明Ag+化CdSeNC中的电子结构和发光机制 (Ag+:CdSe).
- 调和光谱相似性与不同的剂电离潜力.
主要方法:
- 时间分辨率可变温度光发光谱 (PL).
- 磁圆极化发光光谱 (MCPL).
- 时间依赖密度函数理论 (TD-DFT) 电子结构计算.
主要成果:
- Ag+:CdSe和Cu+:CdSe的NC显示了具有较大的斯托克斯转移的可比宽PL.
- 这两种系统具有相似的温度依赖的PL寿命和磁光发光.
- 对于两种药物,TD-DFT预测了类似的局部中间状态.
- 孔在Cu+:CdSe中的Cu(3d) 上,但在Ag+:CdSe中的Se联体上,表明了结合转移.
结论:
- 光谱相似性来自于[MSe4]集群中的孔位 (M = Ag+, Cu+).
- 尽管Cu+:CdSe和Ag+:CdSe具有相似的发光,但它们具有不同的电子结构.
- 从"正常"转向"反向"的结合解释了Ag+与Cu+剂的行为.
- 这些发现使光观测与剂电离能量的基本差异相协调.
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