Optimizing Langmuir-Blodgett Transfer of Nanocrystal Monolayers: Layer Compaction, Layer Compression, and Lattice Stretching of the Transferred Layer

Grazing incidence small angle X-ray scattering (GISAXS) was used to study the structure and interparticle spacing of monolayers of organic ligand-stabilized iron oxide nanocrystals floating at the air-water interface on a Langmuir trough, and after transfer to a solid support by the Langmuir-Blodgett technique. GISAXS measurements of the nanocrystal arrangement at the air-water interface showed that lateral compression decreased the interparticle spacing of continuous films. GISAXS also revealed that Langmuir-Blodgett transfer of the nanocrystal layers to a silicon substrate leads to a stretching of the film, with a significant increase in interparticle spacing.