USA As Represented by Secretary of the Navy

Chase T Ellis

Michael H Stewart

Rhonda Michele Stroud

Steven C Erwin

Joseph G Tischler

Paul D Cunningham

Sarah F Brittman

Janice E Boercker

Patrick Y Yee

A process for synthesizing CuS/PbS core/shell nanocrystals. Pb-oleate is mixed with 1-octadecene and heated to 60&#xb0; C. CuS core solution and bis(trimethylsilyl)sulfide stock solution are added and the mixture is stirred at 60&#xb0; C. for 6 minutes to form the PbS shell around the CuS nanocrystal cores. The flask is cooled and acetonitrile and toluene is added and the mixture is centrifuged to precipitate and remove the CuS/PbS core/shell nanocrystals from the reaction mixture. The reaction also produces homogeneously nucleated PbS nanocrystals, which are removed from the CuS/PbS core/shell reaction mixture via size-selective precipitation. By tailoring the amounts of Pb-oleate and bis(trimethylsilyl)sulfide stock solution in the reaction vessel, while maintaining their molar ratio of 1.5:1 and the number of CuS cores in the reaction, CuS/PbS core/shell nanocrystals having a predetermined shell thickness of PbS, and thus a predetermined level of chemical stability, can be obtained.

Core/shell nanocrystals with copper sulfide cores and lead sulfide shells

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Silver Spring, MD, United States of America

Chase T Ellis