Cluster‐assembled materials: Ordered structures with advanced properties

Abstract

Cluster‐assembled materials (CAMs) present delicate structures and tailored properties, which have gained extensive interest in recent years. Due to the noncovalent linkage and size of sub‐1 nm, clusters present polymer‐like solution behaviors distinct from conventional nanocrystals, whereby a variety of CAMs with different constructions have been fabricated. To our knowledge, the morphologies and properties of CAMs are closely connected, which are strongly dependent on the structure and coordination state of cluster building blocks. For the CAMs with superior performances, the specific arrangement and surroundings of clusters at subnanometer scale usually result in well‐organized structures. In this review, we will summarize the recent progress of CAMs with highly ordered structures and advanced properties, where polyoxometalate cluster assemblies as well as cluster–nuclei co‐assemblies are involved. The application potentials of CAMs are then discussed, especially on the cluster arrangements and interactions at subnanometer scale. However, current researches are far from reaching the point, and future efforts are needed before the nature of cluster‐based nanostructures can be sufficiently revealed. We hope this article can offer unique insights and instructive understanding to the CAMs.

Polyoxometalate-based materials: quasi-homogeneous single-atom catalysts with atomic-precision structures

“…The multiple interactions between cluster building blocks and surrounding components, such as electrostatic interactions, hydrogen bonding, coordination bonding, van der Waals forces, and solvophobic interactions, may have a large influence on the electronic structures and properties of clusters, finally causing differences in catalytic performance. 70 Moreover, the insertion of a metal atom results in anisotropic POM building blocks, where specific growth orientations and neoteric morphologies may emerge in the assembly. POM assemblies with ultrathin or single-cluster constructions may present enhanced catalytic activities and stability due to the fully exposed active centers and stable connections between cluster units.…”

Organic–inorganic hybrid cathode interlayer materials for efficient organic solar cells

“…On the other hand, oxide clusters, especially some kinds of metal-oxo clusters, have been studied as molecular models of their metal oxide nanoparticle counterparts. [135][136][137][138][139] The clusters are usually synthesized with atomically precise structures and can display similar physicochemical properties to the corresponding metal oxides. The synthesis is usually nished with a sol-gel process under solvothermal conditions with considerable yields and batch scales.…”

Fabricating sub-nanometer materials through cluster assembly

“…[18][19][20][21][22] In addition, interactions between cluster building blocks can significantly affect their electronic structures and properties, leading to the enhanced properties of cluster-based assemblies compared to individual building blocks. [23][24][25] Polyoxometalate (POM) and noble metal clusters are subnanometer metal oxide and metal nanoparticles, respectively, with atomic precision structures and geometries. 26,27 As the most representative cluster species, the synthesis and assembly of POM and noble metal clusters have been comprehensively studied in the past few decades.…”

“…18–22 In addition, interactions between cluster building blocks can significantly affect their electronic structures and properties, leading to the enhanced properties of cluster-based assemblies compared to individual building blocks. 23–25…”