Site-Specific Ligand Interactions Favor the Tetragonal Distortion of PbS Nanocrystal Superlattices
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- 作者：Jiřı́ Novák ; Rupak Banerjee ; Andreas Kornowski ; Maciej Jankowski ; Alexander André ; Horst Weller ; Frank Schreiber ; Marcus Scheele
- 刊名：ACS Applied Materials & Interfaces
- 出版年：2016
- 出版时间：August 31, 2016
- 年：2016
- 卷：8
- 期：34
- 页码：22526-22533
- 全文大小：564K
- 年卷期：0
- ISSN：1944-8252
文摘
We analyze the structure and morphology of mesocrystalline, body-centered tetragonal (bct) superlattices of PbS nanocrystals functionalized with oleic acid. On the basis of combined scattering and real space imaging, we derive a three-dimensional (3D) model of the superlattice and show that the bct structure benefits from a balanced combination of {100}PbS–{100}PbS and {111}PbS–{111}PbS interactions between neighboring layers of nanocrystals, which uniquely stabilizes this structure. These interactions are enabled by the coaxial alignment of the atomic lattices of PbS with the superlattice. In addition, we find that this preferential orientation is already weakly present within isolated monolayers. By adding excess oleic acid to the nanocrystal solution, tetragonal distortion is suppressed, and we observe assembly into a bilayered hexagonal lattice reminiscent of a honeycomb with grain sizes of several micrometers.