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How Robust are Semiconductor Nanorods? Investigating the Stability and Chemical Decomposition Pathways of Photoactive Nanocrystals

TitleHow Robust are Semiconductor Nanorods? Investigating the Stability and Chemical Decomposition Pathways of Photoactive Nanocrystals
Publication TypeJournal Article
Year of Publication2014
AuthorsReichert, MD, Lin, CC, Vela, J
JournalChemistry of Materials
Volume26
Pagination3900-3908
Date Published07
Type of ArticleArticle
ISBN Number0897-4756
Accession NumberWOS:000338806700007
Keywordscadmium-sulfide, cdse quantum dots, highly efficient, magnetically recyclable photocatalyst, metal nanoparticles, nanostructures, particles, photochemistry, reactivity, visible-light
Abstract

nanorods as model systems, we have investigated the behavior of II-VI semiconductor nanorods against various conditions of extreme chemical and physical stress (acids, bases, oxidants, reductants, and heat). CdSe nanorods react rapidly with acids, becoming oxidized to Se or SeO2. In contrast, CdSe nanorods remain mostly unreactive when treated with bases or strong oxidants, although bases do partially etch the tips of the nanorods (along their axis). Roasting (heating in air) of CdSe nanorods results in rock-salt CdO, but neither CdSe nor CdO is easily reduced by hydrogen (H-2). Another reductant, n-BuLi, reduces CdSe nanorods to metallic Cd. Variable temperature X-ray diffraction experiments show that axial annealing and selective axial melting of the nanorods precede particle coalescence. Furthermore, thermal analysis shows that the axial melting of II-VI nanorods is a ligand-dependent process. In agreement with chemical reactivity and thermal stability observations, silica-coating experiments show that the sharpest (most curved) II-VI surfaces are most active against heterogeneous nucleation of a silica shell. These results provide valuable insights into the fate and possible ways to enhance the stability and improve the use of II-VI semiconductor nanostructures in the fields of optics, magnetism, and energy conversion.

DOI10.1021/cm500896n
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