1. Adrienne Borchardt

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

3. Quantum Dots (QDs) Sources: http://www.tnw.tudelft.nl/live/pagina.jsp?id=5550e07d-ec54-4f77-bcf0- 5736863ef4b8&lang=en; http://www.aist.go.jp/aist_e/aist_today/2006_21/hot_line/hot_line_22.html

4. Applications  Light-Emitting Diodes (LEDs)  Photovoltaic Devices  Biological Sensors  Quantum Computation  Dyes  Display Technology Sources: http://www.phbeta.com/samsung/samsung-electronics-created-the-first-full-color-display-with-quantum-dots/; http://www.instructables.com/id/LED-Throwies/; http://www.sciencemag.org/content/307/5709/538/F4.large.jpg; http://inhabitat.com/colored-solar-panels-dont-need-direct-sunlight/green-sun-colored-solar-panels-4/

5. 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.

6. 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.

7. Metal Salt Study

8. CdSe Core  (CdSe) 33 and (CdSe) 34 core  Most stable A. Kasuya et al. Nature Mater. 2004, 3, 99-102.c

9. Charge Deconvolution Mass Spectrometry Sources: http://sydney.edu.au/science/molecular_bioscience/facilities/mass.php

10. MS of MSA-CdSe QDs   m/z ~ 44

11. Water-Soluble Thiols 4.60 4.34 3.64 3.30 3.51

12. 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.

13. pH Effects on Fluorescence  Aggregation

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

15. 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

16. Acknowledgements  NSF CHE-095940  Dr. Deon Miles  The Sewanee Chemistry Department