Structural Basis for Near Unity Quantum Yield Core/Shell Nanostructures

• Published in: Nano letters Vol. 6; no. 7; pp. 1496 - 1501
• Main Authors: McBride, James, Treadway, Joe, Feldman, L. C, Pennycook, Stephen J, Rosenthal, Sandra J
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.07.2006
• Subjects: Cadmium Compounds - chemistry; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Microscopy, Electron, Scanning Transmission; Nanoscale materials and structures: fabrication and characterization; Nanostructures - chemistry; Other topics in nanoscale materials and structures; Physics; Quantum Dots; Sulfides - chemistry; Theory and models of film growth; Zinc Compounds - chemistry; Core shell structure; Aberrations; Growth mechanism; Sublattices; Scanning transmission electron microscopy; Quantum yield; Nanostructured materials; Nanorod
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl060993k

Aberration-corrected Z-contrast scanning transmission electron microscopy of core/shell nanocrystals shows clear correlations between structure and quantum efficiency. Uniform shell coverage is obtained only for a graded CdS/ZnS shell material and is found to be critical to achieving near 100% quantum yield. The sublattice sensitivity of the images confirms that preferential growth takes place on the anion-terminated surfaces. This explains the three-dimensional “nanobullet” shape observed in the case of core/shell nanorods.