Cu2-xS/PbS Core/Shell Nanocrystals

A process for synthesizing Cu2-xS/PbS core/shell nanocrystals, comprising:

• mixing a predetermined amount of Pb-oleate with 1-octadecene in a reaction flask within an N2 glovebox to form a Pb-oleate mixture;
• removing the flask from the glovebox and heating the Pb-oleate mixture under an argon atmosphere to 60° C.;
• while maintaining the temperature of the Pb-oleate mixture at 60° C., adding a predetermined amount of a predetermined Cu2-xS core hexane solution and a predetermined amount of bis(trimethylsilyl)sulfide stock solution to the Pb-oleate mixture to form a reaction mixture, the amounts of the Pb-oleate and bis(trimethylsilyl)sulfide stock solution being maintained at a Pb-oleate:bis(trimethylsilyl)sulfide molar ratio of 1.5:1;
• rapidly stirring the reaction mixture (700 rpm) for 6 minutes to form the Cu2-xS/PbS core/shell nanocrystals from the reaction mixture;
• cooling the flask to room temperature;
• returning the flask to the N2 glovebox and adding toluene and acetonitrile to the flask in the glovebox;
• removing the reaction mixture from the flask and placing it in a centrifuge tube;
• and
• centrifuging the reaction mixture to precipitate and remove the Cu2-xS/PbS core/shell nanocrystals from the reaction mixture;
• wherein the amount of the Pb-oleate and the amount of the bis(trimethylsilyl)sulfide stock solution are configured to produce a predetermined number of PbS monolayers on the Cu2-xS cores.