Energy induced nanoparticle substrate interactions

现有的自上而下或自下而上的纳米颗粒合成方法通常工作在接近甚至达到热力学平衡的情况下，并且受到溶解度限制或表面重建的挑战。另一种选择是在特定环境中通过能量冲击对制备的纳米颗粒进行后续修饰，以开发具有不寻常甚至奇异性质的新的纳米结构材料。更普遍的是，纳米颗粒的功能是通过与特定环境和/或支持基质在给定的能量影响下发生的相互作用过程来实现的！因此，界面上的演化和反应，特别是纳米颗粒和支持底物之间的反应，是非常重要的。不同的化学和物理过程在多个尺度上发生：例如，化学反应仅在原子尺度上发生，热冲击导致界面合金的形成，以及离子撞击等过程导致原子的弹道混合。尽管已经分别研究了几个方面，但到目前为止，还没有制定和获得所有涉及的过程的统一和一致的图景。识别特定环境中由物理和/或化学能量引起的纳米颗粒基质相互作用的异同，一方面将促进开发具有特殊性能的新材料，另一方面将明确其功能。这一挑战将在我们的联合提案中得到解决。我们的目标是确定化学和物理能量对金属纳米颗粒和硅基衬底材料之间相互作用的一般影响，以便深入了解潜在的过程。为了实现这一目标，我们将通过实验研究在(A)热、(B)离子辐照和(C)化学反应的能量撞击过程中对负载型金属纳米颗粒阵列的化学和物理效应。对激光照射下纳米粒子与基质的相互作用进行了广泛的研究，发表的结果将与我们的实验结果一起得出全面的结论。将使用各种高分辨率技术来监测结构的演变，包括电子显微镜、电子色散X射线光谱、电子背散射衍射和原子力显微镜。结合我们的化学和物理背景，这三种平行方法将使我们能够分离和确定潜在机制和影响的相互作用。除了合金化和弹道混合外，还将而且必须考虑纳米尺度上的表面和界面能/力、不同的晶体取向、相图、塑性流动、催化反应和化学键，以便充分和有效地理解纳米粒子-衬底在能量碰撞时的相互作用。

Established top-down or bottom-up syntheses methods for nanoparticles often work close or even at thermodynamic equilibrium and are challenged by solubility limits or surface reconstructions. An alternative option is the subsequent modification of prepared nanoparticles by means of energy impact in a specific environment in order to develop new nanostructured materials with unusual or even exotic properties. Even more general, the functionality of nanoparticles is given by the occurring interaction processes with specific environments and/or supporting substrates upon a given energy impact! Thus, the evolution and reactions at interfaces, especially e.g. between nanoparticles and supporting substrates, are of great importance. Different chemical and physical processes take place at multiple scales: e.g. chemical reactions occur solely at atomic scales, thermal heat impact leads to the formation of interface alloys, and processes such as ion impact results in ballistic mixing of atoms. Even though several aspects have already been studied separately, a uniform and consistent picture of all involved processes has not been formulated and obtained until now. Identification of similarities and differences in nanoparticle substrate interactions induced by physical and/or chemical energy in specific environments would, on one hand, promote developing new materials with exceptional properties, and, on the other hand, specify their functionality.Exactly this challenge will be addressed in our joint proposal. We aim to identify the general impact of chemical and physical energy on the interaction between metallic nanoparticles and Si-based substrate materials in order to gain a deep understanding of the underlying processes. To achieve this goal, we will experimentally study chemical and physical effects on supported metal nanoparticle arrays taking place during energy impact by (a) heat, (b) ion irradiation, and (c) chemical reactions. Nanoparticle substrate interactions upon laser irradiation are vastly investigated, and the published results will be used to draw comprehensive conclusions together with our experimental results. The structural evolution will be monitored with various high-resolution techniques including electron microscopy, electron dispersive X-ray spectroscopy, electron back scattered diffraction, and atomic force microscopy. The three parallel approaches, with our chemical and physical background, will allow us the separation and the determination of the interplay of the underlying mechanism and effects. Surface and interface energies/forces at the nano-scale, different crystallographic orientations, phase diagrams, plastic flow, catalytic reactions and chemical bonding will and must be also considered besides alloying and ballistic mixing in order to obtain a full and valid understanding of nanoparticle-substrate interactions upon energy impact.