Paper EM-MoA8
Assembly of Functional Nanocrystal Films at Fluid Interfaces

Monday, November 10, 2014, 4:20 pm, Room 314

Opportunities to create materials with properties by design continue to emerge from our ability to control the structure and composition of nanomaterials through wet-chemistry synthesis methodologies. Access to these materials has provided critical insights into basic structure-property relationships. Concurrent advances in prototype nanomaterial-based devices underscored their immense technological potential in a broad range of energy applications including p hotovoltaics, catalysis, energy storage, and thermoelectrics. Along with rising expectations, there is growing recognition that sustained progress towards the acclaimed promise of nanomaterial-enabled energy technologies depends critically on solving outstanding processing challenges - in particular the dir ected assembly of nanoparticles (NPs) into functional superstructures. We embrace this challenge as an opportunity to establish the scientific and engineering foundation for the processing of ordered and multifunctional NP thin films via advanced liquid coating methods.

Our group recently demonstrated a significant advance to resolve this challenge by creating NP assemblies that combine high spatial coherence and strong interparticle electronic coupling. In brief, we discovered that spreading a NP suspension across the surface of a non-polar antisolvent subphase results in the formation of two-dimensional ( 2D ) superlattice of epi taxially connected NP s. Our app roach to ‘connect the dots’ was inspired by analogies to polymerize or crosslink NP s as monomers into highly connected superstructures. The ability to form ‘confined-but-connected’ 2D NP assemblies with predefined symmetries introduces exciting opportunities to create materials with properties by design. By analogy to atomic 2D systems (e.g. graphene), we see 2D NP assemblies as a fertile ground for scientific discovery with a clear path towards practical applications.