Free-standing nanoparticle superlattice sheets: From design to applications

Wenlong Cheng
2017 Europhysics letters  
Here I summarize my perspective in free-standing nanoparticle superlattice sheets with regards to their fabrication, properties, and applications. Why free-standing?-Nanoparticles have been coined as "artificial atoms" due to their unique size/shapedependent optical, electrical, magnetic and conductive properties. Encouraging progress made over the past several decades allows for controlling nanoparticles sizes and shapes, enabling the formation of the so-called "artificial periodic table" [1]
more » ... The crystallization of these artificial atoms into highly-ordered arrays represents a unique strategy to design metamaterials with collective properties different from those of bulk phase crystals, isolated nanocrystals and even disordered nanocrystal assemblies [2-6]. These unusual properties include spin properties [7], metal-insulator transition [2], mechanical properties [4, 8] , p-type conductivities [5], vibrational coherence [3], and plasmonic properties [9] [10] [11] . In addition, diverse types of lattice structures have been found including face-centered cubic, body-centered cubic, hexagonal closed-packed, diamond-like lattice, and lattice structures not existing in nature [12] . It has to be noted that the majority of these studies focus on solid-substrate-supported nanoparticle superlattices or solution-state nanoparticle superlattices. In contrast, free-standing nanoparticle superlattice sheets refer to suspended ordered nanoparticle arrays with minimal contact with the solid substrate. Compared to dominant solid-substrate-supported or solution-state systems, free-standing nanoparticle superlattice sheets (a) Contribution to the Focus Issue Self-assemblies of Inorganic and Organic Nanomaterials edited by Marie-Paule Pileni. (b)
doi:10.1209/0295-5075/119/48004 fatcat:qvxfemr2gfcnfnv4qi4rsjhre4