Cluster Superlattice Membranes

团簇超晶格膜是一种新型的二维材料。这种膜由位于二维六边形阵列的簇组成，晶格常数为2-4 nm。团簇的晶格具有原子精度，但比原子尺度更大，因此是超晶格。团簇超晶格被夹在原子厚度的单晶二维层和纳米厚度的嵌入矩阵之间，使得矩阵与团簇和二维层一起形成一个机械稳定的薄片，可以有mm的横向延伸。它的机械完整性使其能够从一个宿主基质转移到另一个基质，或用作独立膜。簇的大小可调，从单个原子限制到大约400个原子。提出的研究这些新的二维材料的目的是三重的。首先，它的目标是发展这种膜的制造，以获得材料的多样性。这将包括实现开放膜，这样簇可以与环境相互作用，例如在电催化中的应用。簇后生长和开放膜与新型金属膜的结合将拓宽其在纳米磁性研究中的应用潜力。实现以氧化物为主体材料的膜将获得光学和电传输特性，并在高温下实现多相催化。其次，将彻底分析膜的性能，即它们在恶劣环境下的抗渗性和稳定性。特别令人感兴趣的是它们的高温行为。本文预测了优异的抗烧结性能，包括抑制Smoluchowski成熟和逆Ostwald成熟。第三，为了证明这些团簇超晶格膜在基础研究中的潜力，我们将构建磁性粒子膜并分析它们的磁相互作用。承载团簇的膜腔将被用作小颗粒相变的反应器，否则这是不可能的。在碳和氧化物基质中开放的贵金属超晶格膜将在液体和气体环境中作为催化剂进行测试。

Cluster superlattice membranes are a new type of two dimensional (2D) material. Such a membrane consists of clusters positioned in a 2D hexagonal array with a lattice constant of 2-4 nm. The lattice of clusters is of atomic precision, but of larger than atomic scale, and thus a superlattice. The cluster superlattice is sandwiched between a single crystal 2D layer of atomic thickness and an embedding matrix of nm thickness, such that the matrix together with the clusters and the 2D layer forms a mechanically stable sheet which can have mm lateral extension. Its mechanical integrity enables the transfer from a host substrate to another substrate or its use as a freestanding membrane. The clusters are tunable in size from the single atom limit up to about 400 atoms. The objective of the proposed research with these new 2D materials is threefold. First, it is the goal to develop the making of such membranes in order to obtain materials in a large diversity. This will include the realization open membranes, such that the clusters can interact with the environment, e.g. for applications in electrocatalysis. Post growth of clusters and combining open membranes with new metallic films will broaden their application potential for nanomagnetic investigations. Realization of membranes with oxides as a host material will give access to optical as well as electrical transport properties, and enable heterogeneous catalysis at elevated temperatures. Second, the membrane properties will be thoroughly analyzed, namely their proposed impermeability and stability in harsh environments. Of specific interest is their high temperature behavior. Here, excellent resistance against sintering is predicted, including suppression of Smoluchowski ripening and inverse Ostwald ripening. Third, to demonstrate the potential of these cluster superlattice membrane in fundamental research, we will construct membranes of magnetic particles and analyze their magnetic interaction. The cavities of the membranes that host the clusters will be used as reactors for phase transformations in small particles that otherwise would not be possible. Open noble metal superlattice membranes in carbon and oxide matrix will be tested as catalysts in liquid and gaseous environments.