Building Materials from Colloidal Nanocrystal Arrays: Preventing Crack Formation during Ligand Removal by Controlling Structure and Solvation

Abstract

Crack-free, ligand-free, phase-pure nanostructured solids, using colloidal nanocrystals as precursors, are fabricated by a scalable and facile approach. Films produced by this approach have conductivities comparable to those of bulk crystals over more than 1 cm (1.370 S cm for PbS films).

Simplicity as a Route to Impact in Materials Research

“…Damage and reactivity with the surface of the nanocrystals can be completely controlled with the appropriate choice of feed gas. Cracking can be entirely avoided by controlling the assembly of the nanoparticles (disordered arrays resist cracking) . The result is a phase‐pure polycrystal with a nanostructure that is entirely determined by its original building blocks (Figure b).…”

“…High performance . The electrical conductivities of PbS assemblies produced through this approach over 1 cm to be 1.370 S cm −1 which is comparable to bulk crystal . This conductivity value is remarkable considering the fact that the typical porosity in fully processed CNAs is around 40%.…”

“…The simplicity of the approach results in remarkable stackability. Mixture of phases that would be impossible to grow together can be easily produced by mixing dispersions of nanocrystals of different phases, thereby providing opportunities for the design of supercapacitors, batteries, solar cells, and more . Hackability .…”

Contribution of Ligand Oxidation Products to High Durability of Copper Films Prepared from Low‐Sintering‐Temperature Copper Ink on Polymer Substrates

“…More recently, besides low‐temperature sintering of Cu‐based inks, ensuring the durability of sintered Cu films to safeguard their environmental stability and mechanical flexibility has become the most important task from a practical standpoint . The mechanical properties of sintered Cu films on flexible substrates are an important factor of their practical application to flexible devices.…”

“…The mechanical properties of sintered Cu films on flexible substrates are an important factor of their practical application to flexible devices. Unfortunately, nanoparticle‐based inks cause many problems regarding mechanical cracking in the joints of sintered nanoparticle films, which result in low durability of sintered copper films under repetitive bending. Some approaches have been proposed to increase the mechanical durability of the sintered copper film by mixing other fillers such as carbon nanotubes (CNTs) and nanowires (NWs) .…”