当前位置:
X-MOL 学术
›
Nanoscale Adv.
›
论文详情
Our official English website, www.x-mol.net, welcomes your
feedback! (Note: you will need to create a separate account there.)
The non-stationary case of the Maxwell-Garnett theory: growth of nanomaterials (2D gold flakes) in solution
Nanoscale Advances ( IF 4.6 ) Pub Date : 2019/12/04 , DOI: 10.1039/c9na00636b Prakash Natarajan 1 , Awad Shalabny 1 , Sumesh Sadhujan 1 , Ahmad Idilbi 1 , Muhammad Y Bashouti 1, 2
Nanoscale Advances ( IF 4.6 ) Pub Date : 2019/12/04 , DOI: 10.1039/c9na00636b Prakash Natarajan 1 , Awad Shalabny 1 , Sumesh Sadhujan 1 , Ahmad Idilbi 1 , Muhammad Y Bashouti 1, 2
Affiliation
The solution-based growth mechanism is a common process for nanomaterials. The Maxwell-Garnett theory (for light–matter interactions) describes the solution growth in an effective medium, homogenized by a mean electromagnetic field, which applies when materials are in a stationary phase. However, the charge transitions (inter- and intra-transitions) during the growth of nanomaterials lead to a non-stationary phase and are associated with time-dependent permittivity constant transitions (for nanomaterials). Therefore, time-independence in the standard Maxwell-Garnett theory is lost, resulting in time dependence, εi(t). This becomes important when the optical spectrum of a solution needs to be deconvoluted at different reaction times since each peak represents a specific charge/energy transfer with a specific permittivity constant. Based on this, we developed a time-resolved deconvolution approach, f(t) ∝ εi(t), which led us to identify the transitions (inter- and intra-transitions) with their dominated growth regimes. Two gold ion peaks were precisely measured (322 nm and 367 nm) for the inter-transition, and three different polyaniline oxidation states (PAOS) for the intra-transition, including A (372 nm), B (680 nm), and C (530 nm). In the initial reaction time regime (0–90 min), the permittivity constant of gold was found to be highly dependent on time, i.e. fE ∝ εi(t), since charge transfer takes place from the PAOS to gold ions (i.e. inter-transition leads to a reduction reaction). In the second time regime (90–180 min), the permittivity constant of gold changes as the material deforms from 3D to 2D (fS ∝ ε3D–2D), i.e. intra-transition (combined with thermal reduction). Our approach provides a new framework for the time-dependent modelling of (an)isotropic solutions of other nanomaterials and their syntheses.
中文翻译:
麦克斯韦-加内特理论的非平稳情况:纳米材料(二维金片)在溶液中的生长
基于溶液的生长机制是纳米材料的常见过程。麦克斯韦-加内特理论(用于光与物质相互作用)描述了有效介质中溶液的生长,通过平均电磁场均匀化,该理论适用于材料处于静止相的情况。然而,纳米材料生长过程中的电荷跃迁(内部跃迁和内部跃迁)会导致非稳态相,并与时间相关的介电常数跃迁(对于纳米材料)相关。因此,标准麦克斯韦-加内特理论中的时间无关性消失,导致时间依赖性ε ( t )。当溶液的光谱需要在不同的反应时间进行解卷积时,这一点变得很重要,因为每个峰代表具有特定介电常数的特定电荷/能量转移。基于此,我们开发了一种时间分辨反卷积方法f ( t ) ∝ ε ( t ),该方法使我们能够识别转变(内部和内部转变)及其主导的增长机制。精确测量了内部跃迁的两个金离子峰(322 nm 和 367 nm),以及内部跃迁的三种不同的聚苯胺氧化态 (PAOS),包括 A (372 nm)、B (680 nm) 和 C (530 纳米)。在初始反应时间范围(0-90 分钟)中,金的介电常数被发现高度依赖于时间,即 f E ∝ ε ( t ),因为电荷从 PAOS 转移到金离子(即-转变导致还原反应)。 在第二个时间范围(90–180 分钟)中,金的介电常数随着材料从 3D 变形到 2D ( f S ∝ ε 3D–2D ) 发生变化,即内部转变(与热还原相结合)。我们的方法为其他纳米材料及其合成的(非)各向同性解决方案的时间相关建模提供了新的框架。
更新日期:2020-03-19
中文翻译:
麦克斯韦-加内特理论的非平稳情况:纳米材料(二维金片)在溶液中的生长
基于溶液的生长机制是纳米材料的常见过程。麦克斯韦-加内特理论(用于光与物质相互作用)描述了有效介质中溶液的生长,通过平均电磁场均匀化,该理论适用于材料处于静止相的情况。然而,纳米材料生长过程中的电荷跃迁(内部跃迁和内部跃迁)会导致非稳态相,并与时间相关的介电常数跃迁(对于纳米材料)相关。因此,标准麦克斯韦-加内特理论中的时间无关性消失,导致时间依赖性ε ( t )。当溶液的光谱需要在不同的反应时间进行解卷积时,这一点变得很重要,因为每个峰代表具有特定介电常数的特定电荷/能量转移。基于此,我们开发了一种时间分辨反卷积方法f ( t ) ∝ ε ( t ),该方法使我们能够识别转变(内部和内部转变)及其主导的增长机制。精确测量了内部跃迁的两个金离子峰(322 nm 和 367 nm),以及内部跃迁的三种不同的聚苯胺氧化态 (PAOS),包括 A (372 nm)、B (680 nm) 和 C (530 纳米)。在初始反应时间范围(0-90 分钟)中,金的介电常数被发现高度依赖于时间,即 f E ∝ ε ( t ),因为电荷从 PAOS 转移到金离子(即-转变导致还原反应)。 在第二个时间范围(90–180 分钟)中,金的介电常数随着材料从 3D 变形到 2D ( f S ∝ ε 3D–2D ) 发生变化,即内部转变(与热还原相结合)。我们的方法为其他纳米材料及其合成的(非)各向同性解决方案的时间相关建模提供了新的框架。