To grow the shell structure, we first mixed 0.42 mol of sulfur, 1.0 g TOP and 1.0 g TOPO together and heated the mixture to 150 ◦C to get a clear solution (solution 1).
Next, 0.2mmol of Se and 2.0 g of TOP were mixed together and heated to 150 ◦C to get another clear solution (solution 2).
Solutions 1 and 2 were injected into the reaction mixture mentioned above, and the growth of CdSe/CdS QDs was monitored continuously by checking the fluorescence of the solution.