Octapod-Shaped Colloidal Nanocrystals of Cadmium Chalcogenides via “One-Pot” Cation Exchange and Seeded Growth

• Published in: Nano letters Vol. 10; no. 9; pp. 3770 - 3776
• Main Authors: Deka, Sasanka, Miszta, Karol, Dorfs, Dirk, Genovese, Alessandro, Bertoni, Giovanni, Manna, Liberato
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 08.09.2010
• Subjects: Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals; Physics; Structure of solids and liquids; crystallography; Quantum dot; multipod; semiconductor; heterostructure; tetrapod; octapod; Cadmium; Symmetry property; Crystal seeds; Cadmium sulfide; Cadmium selenides; Chalcogenides; Sphalerite; II-VI semiconductors; Cadmium tellurides; Growth mechanism; Copper sulfide; Ion exchange; Nanostructured materials; Heterostructures; Nanocrystal
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl102539a

The growth behavior of cadmium chalcogenides (CdE = CdS, CdSe, and CdTe) on sphalerite Cu2−x Se nanocrystals (size range 10−15 nm) is studied. Due to the capability of Cu2−x Se to undergo a fast and quantitative cation exchange reaction in the presence of excessive Cd2+ ions, no Cu2−x Se/CdE heterostructures are obtained and instead branched CdSe/CdE nanocrystals are built which consist of a sphalerite CdSe core and wurtzite CdE arms. While CdTe growth yields multiarmed structures with overall tetrahedral symmetry, CdS and CdSe arm growth leads to octapod-shaped nanocrystals. These results differ significantly from literature findings about the growth of CdE on sphalerite CdSe particles, which until now had always yielded tetrapod-shaped nanocrystals.