Fabrication, Transfer, and Transport Properties of Monolayered Freestanding Nanoparticle Sheets

Abstract

Nanoparticles, often referred to as ‘artifi cial atoms’, can be arranged into 1D, [ 1 , 2 ] 2D, [ 3–6 ] and 3D assemblies, [ 7 , 8 ] in analogy to the formation of crystals by atoms and molecules in nature. These artifi cial solids exhibit unique collective optical, [ 9 ] electrical, [ 10–12 ] and magnetic properties, [ 13 ] which stem from the novel electronic properties of the individual nanoparticles and the coupling between neighboring building blocks. [ 14 ] Motivated by fundamental and practical interests, researchers have developed various techniques to assemble 2D nanoparticle arrays and investigated their properties. [ 9 , 12 , 15 ] Freestanding 2D nanoparticle arrays not only offer a new type of ultrathin, robust, and fl exible material, but also enable the study of substrate-free optical and electrical properties. [ 16 ] Thus far, freestanding nanoparticle membranes have been fabricated by embedding them in polymers, [ 17 , 18 ]