由80个Oligophenylene Dithiol分子组成的金属-分子-金属结合物的运输性能异常小的统计变化
Zuoti Xie, Ioan Bâldea1,2, Abel T Demissie
1Theoretical Chemistry, Heidelberg University , INF 229, D-69120 Heidelberg, Germany.
Journal of the American Chemical Society
|April 11, 2017
概括
有许多并行分子的分子电子连接显示出高可重现性. 这项研究量化了电阻的偏差, 发现它们比单分子连接更小,
科学领域:
- 分子电子
- 纳米技术
- 凝聚物质物理
背景情况:
- 由于随机波动,单分子连接经常表现出广泛的阻力直方图.
- 这种变化阻碍了可靠的分子电子设备的开发.
- 室温测量特别容易受到这些波动的影响.
研究的目的:
- 用多个平行分子研究分子结合的可重现性.
- 量化分析这些结点的阻力偏差来源.
- 将多分子连接与单分子连接的性能进行比较.
主要方法:
- 使用导探原子力显微镜 (CP-AFM) 制造分子连接.
- 在黄金上的自组装单层中利用了寡二醇 (OPD) 分子.
- 使用接触力学,表面覆盖测量和分析运输模型.
主要成果:
- 在约200次测量后,大约有80个平行寡二醇分子的分子结合显示出小的相对电阻偏差 (δR/R ≈25%).
- 可以直接确定连接中的分子数量 (N).
- 分子轨道能量 (δε) 和分子电极合 (δΓ) 的偏差被确定为阻力变化的主要贡献者,而不是分子数量 (δN/N ≤ 2%).
结论:
- 由几十个平行分子组成的连接显示出极好的可重复性.
- 观察到的偏差明显小于单分子断裂连接所报告的偏差.
- 这些发现对于推进强大可靠的分子电子设备的发展至关重要.
相关概念视频
01:16Structure of Conjugated Dienes
Introduction
Conjugated dienes are compounds characterized by the presence of alternating double and single bonds. In a conjugated system like 1,3-butadiene, the unhybridized 2p orbital on each carbon overlaps continuously, allowing the π electrons to be delocalized across the entire molecule. In contrast, this type of overlap does not occur in cumulated and isolated dienes, such as 2,3-pentadiene and 1,4-pentadiene, respectively. Instead, the π electrons remain localized between the double...
Conjugated dienes are compounds characterized by the presence of alternating double and single bonds. In a conjugated system like 1,3-butadiene, the unhybridized 2p orbital on each carbon overlaps continuously, allowing the π electrons to be delocalized across the entire molecule. In contrast, this type of overlap does not occur in cumulated and isolated dienes, such as 2,3-pentadiene and 1,4-pentadiene, respectively. Instead, the π electrons remain localized between the double...
01:29Diels–Alder Reaction: Characteristics of Dienes
The Diels–Alder reaction brings together a diene and a dienophile to form a six-membered ring. Both components have unique characteristics that influence the rate of the reaction.
Characteristics of the diene
Conformation
The simplest example of a diene is 1,3-butadiene, an acyclic conjugated π system. At room temperature, the molecule exists as a mixture of s-cis and s-trans conformers by virtue of rotation around the carbon–carbon single bond. Although the s-trans isomer is more stable, the...
Characteristics of the diene
Conformation
The simplest example of a diene is 1,3-butadiene, an acyclic conjugated π system. At room temperature, the molecule exists as a mixture of s-cis and s-trans conformers by virtue of rotation around the carbon–carbon single bond. Although the s-trans isomer is more stable, the...
01:28Stability of Conjugated Dienes
Introduction
A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs.
A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs.
01:10Polymers: Molecular Weight Distribution
For any given polymer, the weight average molecular weight (Mw) is higher than, if not equal to, the number average molecular weight (Mn). The only situation in which the weight average molecular weight and the number average molecular weight are equal is when a polymer consists only of chains with equal molecular weight. However, this never happens in a synthetic polymer, since it is difficult to control the polymerization process up to a molecular level with accuracy to a hundred percent.
01:13Olefin Metathesis Polymerization: Overview
Recently, the development of olefin metathesis polymerization advanced the field of polymer synthesis. Simply put, the reorganization of substituents on their double bonds between two olefins in the presence of a catalyst is known as the olefin metathesis reaction. The use of metathesis reaction for polymer synthesis is called olefin metathesis polymerization.
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
00:53Olefin Metathesis Polymerization: Acyclic Diene Metathesis (ADMET)
Acyclic diene metathesis polymerization or ADMET polymerization involves cross-metathesis of terminal dienes, such as 1,8-nonadiene, to give linear unsaturated polymer and ethylene. As ADMET is a reversible process, the formed ethylene gas must be removed from the reaction mixture to complete the polymerization process.
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...