Adrienne Borchardt

Overview  What are quantum dots?  Applications  Metal salt study  pH adjustment study CdSe

Quantum Dots (QDs) Sources: ef4b8&lang=en;

Applications  Light-Emitting Diodes (LEDs)  Photovoltaic Devices  Biological Sensors  Quantum Computation  Dyes  Display Technology Sources:

Metal Salt Study Synthesis Reaction Mixture Metal salts: Cd(ClO 4 ) 2 ·H 2 O CdSO 4 CdCl 2 CdCl 2 ·2 ½ H 2 O Thiol: MSA Ligand-to-metal ratio is 2.4:1.

Metal Salt Study Synthesis Procedure The pH is adjusted to ≥ 11 using 1 M NaOH while stirring. Mixture was deaerated for ~30 minutes with N 2. NaHSe solution is added to reaction mixture. Mixture was allowed to reflux over a period of time. Aliquots were collected based on visible change in color.

Metal Salt Study

CdSe Core  (CdSe) 33 and (CdSe) 34 core  Most stable A. Kasuya et al. Nature Mater. 2004, 3, c

Charge Deconvolution Mass Spectrometry Sources:

MS of MSA-CdSe QDs   m/z ~ 44

Water-Soluble Thiols

pH Study Synthesis Reaction Mixture Metal perchlorate: Cd(ClO 4 ) 2 ·H 2 O in Type 1 water. Thiol: MPA, TGA, TIO Ligand-to-metal ratio is 2.4:1. Procedure The same initial procedure was performed. Prior to reflux, seven aliquots of the mixture were removed and pH was adjusted to a range starting at 1 pH unit below pka.

pH Effects on Fluorescence  Aggregation

MS of MPA-CdSe QDs  Time 2  pH 5.271

Future Work  Establishing proper protocol/conditions to obtain mass spectrum of QDs  Actually seeing a definitive mass spectrum of the QDs  Studying other aspects (stability, pH effects) of the QDs using the different metal salts

Acknowledgements  NSF CHE  Dr. Deon Miles  The Sewanee Chemistry Department