OMAR K. ABDI SCIENCE AT THE INTERFACE AUGUST DEPARTMENT OF CHEMISTRY AND BIOLOGY RYERSON UNIVERSITY The Synthesis of Modified Organic Dyes for Improved Integration with a Hole- Transport Material. 1

Opportunities for photovoltaics (PV) 2 A promising next-generation photovoltaic technology Though silicon PV devices are more efficient they have limited design capabilities and are made from more expensive starting materials Advantages of Dye Sensitized Solar Cells vs Silicon PV Transparent Can absorb diffuse light Flexible

Dye-Sensitized Solar Cell (DSSC) 3 The problems inherent in the I - /I 3 - electrolyte Chromophore π-spacer Anchor The dye is the power-house of the cell Hagberg D.P., et al., J. Org. Chem., , 9550

The Dye/Electrolyte Interface 4 The I - /I 3 - electrolyte is corrosive, solubilized in a volatile solven What must we considering in adopting new electrolyte  It must rapidly regenerate the dye  It should not react with the dye  Reduction of charge recombination Replacing the I - /I 3 - liquid electrolyte

Hole-Transport Materials (HTM) 5 Modifying dyes for improved interaction Hole-transport materials regenerate the photo-oxidized dye Daeneke T., et al., Nature. 2011, 3, 211 Liu X., et al., Adv. Mater. 2010, 22, 150 Cappel U.B., et al., J. Phys. Chem. C. 2009, 113, 6275 Liquid Electrolyte Ferrocene Ferrocene improved the open-circuit potential Synthetically modifiable highest efficiencies among non-Iodide/triiodide electrolytes Polymeric Poly-EDOT Poly-EDOT has been implemented in DSSC’s with relatively high efficiencies due to good pore-filling Solid State Spiro-MeOTAD reduced recombination oxidatively stabile

Modified dyes with pendant moieties 6 How do we make these dyes Thiophene derivatives are a good choice for pendant arm groups Stability Extend the conjugation Suitable for coupling reactions Useful appendages:

Synthesis of Dyes with Pendant Moieties 7 More synthetic details

Synthesis of Dyes with Pendant Moieties 8 A family of dye candidates A longer pendant arm is synthesized in this route through the use of a trans- vinyl group Reduces dye aggregation Allows for multiple appendages

Properties of a New Dye Family 9 Properties of our dyes This family of dyes will have different ways of interfacing with a hole-transport materials. Further electrochemical and optical characterization will shed light on their physicochemical properties Voltage (V)

Bridging the Dye Electrolyte Interface Summary and Future work The pendant moieties help to solubilize the hole-transport material to improve interfacial contact. This in- turn will facilitate regeneration of the oxidized dye. Improved short-circuit current would be observed as well. 10

Summary and Future work 11 Dyes with pendant moieties will allow for improved interfacing with hole-transport materials. These arms are also suitable for coupling reactions. Future work will involve coupling the pendant arms with functional groups similar to that found on hole-transport materials. Characterizing these dyes to determine their physico- chemical properties will also be a fruitful endeavour. Thanks for the support

Acknowledgements 12 Current Group Dr. Bryan Koivisto (PI) Dr. Catherine Bonnier (PDF) Devin Machin (BSc) Omar Abdi (BSc) Muhammad Yousaf (MSc)