Conformation of Capping Ligands on Nanoplates: Facet-Edge-Induced Disorder and Self-Assembly-Related Ordering Revealed by Sum Frequency Generation Spectroscopy
journal contributionposted on 17.12.2015, 08:28 by Hao Zhang, Fujin Li, Qingbo Xiao, Hongzhen Lin
Surface-curvature-amplified conformational disorder in alkyl capping ligands has been observed previously when the nanoparticle radii approach the ligand length. Herein, sum frequency generation studies on oleic-acid-capped nanoplates show that even on faceted surfaces with dimensions tens of times greater than the ligand length a significant proportion of gauche defects exist in the capping layer. The molecular disorder on the nanosized facets is attributed to a facet-edge effect, which is diminished when increasing the facet size or assembling the nanofacets side to side. This feature is further explored to probe the self-assembly dynamics of nanoplates.