Biomedical Engineering Reference
In-Depth Information
FIGURE 2.3
QD synthesis setup.
Courtesy of Ocean NanoTech.
(For color version of this figure,
the reader is referred to the online version of this topic)
(e)
Elemental selenium is toxic by inhalation, absorption through the skin, and
the effects of ingestion are cumulative.
(f)
Cadmium oxide is highly toxic and cadmium compounds are human car-
cinogens if inhaled or swallowed.
(g)
All leftover CdO, Se, and CdSe octadecene solutions should be collected in
a waste container for proper disposal.
(h)
All glassware must be soaked in soap and water before clean up.
57
2.1.2 QD Core/Shell Synthesis Protocol
The ZnS precursor is prepared using tributylphosphine (TBP), diethylzinc
(ZnEt
2
), and hexamethyldisilathiane ((TMS)2S).
(1)
Purge the TBP with nitrogen for 10-15 min before use.
(2)
Simultaneously, purge a 50-mL round-bottom flask sealed with septa and
containing a stir bar with nitrogen.
(3)
Using a syringe, transfer 5.6 mL of TBP into the flask.
(4)
Purge the ZnEt
2
with nitrogen for 5 min.
(5)
Using a syringe, transfer 0.22 mL (1.04 mmol) of (TMS)2S to the flask
containing the TBP.
(6)
Transfer 1.42 mL (or the desired volume) of ZnEt
2
to the flask containing
TBP and (TMS)2S using a syringe.
(7)
The solution is stirred at 500 rpm, without heating, for 20 min to fully mix.
(8)
Transfer this solution to a vial capped with a septum, then purge with nitro-
gen for 5-10 min. The solutions could be stored for up to one week without
significant degradation. If the solution turned cloudy, it was a sign of deg-
radation due to oxygen exposure, and the solution was discarded.
(9)
Heat the oil bath to 160 °C and allow it to stabilize for 20 min.
