Samples for XRD and SEM are prepared as follows: the colloidal
solution of cysteamine-capped ZnS QDs is first centrifuged at
6000 rpm for 30 min to obtain a white pellet consisting of the QDs.
This pellet is washed twice with ethanol with centrifugation after
each wash, and finally left to dry at room temperature for 24 h. FTIR
was conducted by using PerkinElmer 400