Designing PbSe Nanowires and Nanorings through Oriented Attachment of Nanoparticles

TLDR

PbSe nanocrystals bind on {100}, {110}, or {111} faces depending on surfactants, and a noncentrosymmetric arrangement of {111} facets can create a dipole that drives one‑dimensional oriented attachment into nanowires. Single‑crystal PbSe nanowires are synthesized in solution by oriented attachment of nanocrystal building blocks. By controlling reaction temperature (190–250 °C) and surfactant composition, nearly defect‑free nanowires with uniform diameters (4–20 nm) and lengths up to ~30 µm are produced, and the same conditions can yield zigzag, helical, branched, tapered wires and single‑crystal nanorings.

Abstract

Single-crystal PbSe nanowires are synthesized in solution through oriented attachment of nanocrystal building blocks. Reaction temperatures of 190-250 degrees C and multicomponent surfactant mixtures result in a nearly defect-free crystal lattice and high uniformity of nanowire diameter along the entire length. The wires' dimensions are tuned by tailoring reaction conditions in a range from approximately 4 to approximately 20 nm in diameter with wire lengths up to approximately 30 microm. PbSe nanocrystals bind to each other on either {100}, {110}, or {111} faces, depending on the surfactant molecules present in the reaction solution. While PbSe nanocrystals have the centrosymmetric rocksalt lattice, they can lack central symmetry due to a noncentrosymmetric arrangement of Pb- and Se-terminated {111} facets and possess dipole driving one-dimensional oriented attachment of nanocrystals to form nanowires. In addition to straight nanowires, zigzag, helical, branched, and tapered nanowires as well as single-crystal nanorings can be controllably prepared in one-pot reactions by careful adjustment of the reaction conditions.