Dominique Beamon

in situ Analysis of Click Chemistry and Ferrocene Attachment of Titanium Dioxide

So why are DSSCs not used today?

Dye-Sensitized Solar Cells (DSSCs)• Low manufacturing cost

– No vacuum process– Cheap materials

• Low temp. fabrication for large area• Rough trapping “light harvesting” abilities• Colorful• Flexible

Hagfeldt, A.; Boschloo, G.; Sun, L.; Lars, K.; Pettersson, H. Chem. Rev. 2010, 110.

Anatomy of DSSCsDyeSensitizer

ElectrolyteFTO TiO2

hv

I2-/I-

10-6 s

10-5 s

10-3 s

10-13 s

10-11 s

I3-/I-

10-2 s

10-8 s

10-4 s

Hagfeldt, A.; Boschloo, G.; Sun, L.; Lars, K.; Pettersson, H. Chem. Rev. 2010, 110.

How to improve efficiency?

• Directionality • Surface coverage

e- flow

Why TiO2?

TiO2 Provides• Commercially Available• Nanomaterial with high surface area• Good adhesion to substrate• Uniform coating • Right surface chemistry for dye modification

How can we quantify the chemistry?

Direction of Flow

Flow Cell

ZnSe IRE

How can we measure what’s on the surface?

• Total Internal Reflection– Uses crystals with a higher

refractive index than sample

Goals• Can click chemistry be utilized in the attachment of metals to

our monolayer?

• If so will we be able to run a kinetic analysis of the reaction process?

• Can the degree of completion of the reaction be determined?

• Will the metal be an acceptable way to quantify the absolute surface coverage of the dye molecule?

Building the Monolayer

Azide Stretch

CuAAC?

https://www.scripps.edu/research/technology/clickchem.htmlKolb, H. C.; Finn, M. G.; Sharpless, K. B. Angew. Chem. Int. Ed. Engl. 2001, 40, 2004–2021.

+Cu (I)rt

Alkyne Azide 1, 2, 3 – triazole

Copper Catalyzed Azide Alkyne Cycloaddition

Why Click Chemistry?• Amazing Yields• Greener Chemistry• Neutral pH

• Stereospecific• Supposed Simple Purification• Large thermodynamic driving force

Solvent System0.0017M CuSO4·5H2O/ Ethanol : Water 0.02M Na Ascorbate (Vitamin C)

.034M 1-Hexyne

0.02M Ethynylferrocene

16h

Why so Slow?

Fokin, V. V. J. Am. Chem. Soc. 2005, 127, 210-216

DFT calculated barrier ofStep A) 23.7 kcal/molStep B) 0.7 kcal/molStep C) 14.9 kcal/mol

15

21000.00

0.05

0.10A

bsor

banc

e

Wavenumber

0 mins 5 mins 10 mins 15 mins 20 mins 25 mins 30 mins 35 mins 40 mins 45 mins 50 mins 55 mins 60 mins

Click Reaction Hexyne 66±4%completion

16

0 10 20 30 40 50 600.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

Mat

hem

atic

al A

rea

Time (min)

Click Reaction with Hexyne

k = 0.10±0.05 min-1

TiO2TiO2

+Cu (I)rt

Alkyne Azide 1, 2, 3 – triazole

18

2050 2100 21500.00

0.01

0.02

0.03

Abs

orba

nce

Wavenumber

0 mins 5 mins 10 mins 15 mins 20 mins 25 mins 30 mins 35 mins 40 mins 45 mins 50 mins 55 mins 60 mins 65 mins 70 mins

Ethynylferrocene Click Rxn

50%completion

19

0 10 20 30 40 50 60

0.4

0.5

0.6

0.7

0.8

0.9A

bsor

banc

e

Time (min)

Ethynylferrocene Click Rxn

k = 0.10 min-1

Conclusion• Can click chemistry be utilized in the attachment of metals

to our monolayer?– Absolutely!

• If so will we be able to run a kinetic analysis of the reaction process?– Hexyne: k = 0.10±0.05 min-1

– Ethynyl Ferrocene: k = 0.10 min-1

• Can the degree of completion of the reaction be determined?– Hexyne: 66±4%– Ethynyl Ferrocene: 50%

Future Direction

• Replication of the ethynyl ferrocene click reaction. • Absolute quantification of dye surface coverage.

Acknowledgements• Dr. Karla McCain• Steven Prinslow• Catherine McKenas• Austin College Chemistry Department• Janet and Karen• My Family• Austin Cullen Fund Foundation• Discovery Foundation• Welch Foundation • That guy at Lowe’s• Johnson-Burks Supply Co

Acknowledgements• Dr. Karla McCain• Steven Prinslow• Catherine McKenas• Austin College Chemistry Department• Janet and Karen• My Family• Austin Cullen Fund Foundation• Discovery Foundation• Welch Foundation • That guy at Lowe’s• Johnson-Burks Supply Co