在核心/多量子点中插入一个"原子陷"以进行定向剂迁移
Chun Chu1, Elan Hofman1, Chengpeng Gao1
1Department of Chemistry, Syracuse University Syracuse New York 13244 USA wzhen104@syr.edu.
Chemical science
|December 15, 2023
概括
研究人员使用CdZnS接口层开发了一种"原子陷",以控制量子点 (QD) 中的离子迁移. 这种方法通过降低格子应变来增强多潘特迁移,从而使纳米材料特性能够微调.
科学领域:
- 固态化学和材料科学 固态化学和材料科学
- 纳米技术和量子点合成
- 计算材料科学 计算材料科学
背景情况:
- 晶格中的离子扩散对于固态技术至关重要.
- 控制纳米级网格中的离子扩散存在重大挑战.
- 量子点 (QD) 中的多邦迁移会影响它们的特性,但很难管理.
研究的目的:
- 研究一种控制核心/多量子点 (QDs) 中剂迁移的方法.
- 使用合金接口层作为"原子陷",以促进定向剂迁移.
- 了解兴奋剂部位和格子环境对兴奋剂移动性的影响.
主要方法:
- 核心/多量子点的制造,并插入CdZnS合金接口层.
- 实验观察和分析 (Mn(ii)) 的 dopant 迁移.
- 密度函数理论 (DFT) 计算,以确定剂跳跃的能量障碍.
主要成果:
- CdZnS接口层有效地充当了"原子陷",促进了受控的Mn(ii) 剂迁移.
- 兴奋剂迁移受到宿主格子位置的显著影响;较大的Cd (II) 站点促进了迁移,而较小的Zn (II) 站点则抑制了迁移.
- 与较大的Cd站点相比,DFT的计算证实了Mn的更高的能量障碍,从较小的Zn替代站点跳跃到较大的Cd站点.
结论:
- 通过"原子捕捉"实现受控的剂迁移可以在使用合金接口层的QD中实现.
- 最初的兴奋剂部位和局部格子扭曲极大地影响了兴奋剂的移动性和稳定性.
- 这种方法为调整杂纳米材料特性提供了一种新的策略.
相关概念视频
01:23Atomic Nuclei: Nuclear Relaxation Processes
657
In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis, the precessing magnetic moments are randomly oriented around the z-axis.
657
01:19Mass Analyzers: Common Types
615
The quadrupole mass analyzer consists of four cylindrical metal rods arranged in a diamond carrying a DC voltage and a radio-frequency AC voltage. The motion of ions through the quadrupole depends on the field strength, causing only ions of a certain m/z to resonate successfully and strike the detector at a given field strength. Though the transmission rate for these analyzers is high, the exact elemental composition of the sample is not determined because of low resolution; however, they are...
615
02:42Valence Bond Theory
8.6K
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
8.6K
01:03Atomic Nuclei: Nuclear Spin State Overview
963
NMR-active nuclei have energy levels called 'spin states' that are associated with the orientations of their nuclear magnetic moments. In the absence of a magnetic field, the nuclear magnetic moments are randomly oriented, and the spin states are degenerate. When an external magnetic field is applied, the spin states have only 2 + 1 orientations available to them. A proton with = ½ has two available orientations. Similarly, for a quadrupolar nucleus with a nuclear spin value of...
963
03:02Colors and Magnetism
11.7K
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
11.7K
03:26Electron Configuration of Multielectron Atoms
41.6K
The alkali metal sodium (atomic number 11) has one more electron than the neon atom. This electron must go into the lowest-energy subshell available, the 3s orbital, giving a 1s22s22p63s1 configuration. The electrons occupying the outermost shell orbital(s) (highest value of n) are called valence electrons, and those occupying the inner shell orbitals are called core electrons. Since the core electron shells correspond to noble gas electron configurations, we can abbreviate electron...
41.6K