Dye Sensitised Solar Cells Electricity from berries!

Introduction You’ll be putting together a Dye Sensitised Solar Cell (DSSC) over the course of this workshop This will include: –Soaking a titanium dioxide electrode with dye (from blackberries) –Coating conductive glass with carbon to form a second electrode –Assembling solar cell and adding electrolyte solution

How do they work?

Part 1 Soaking the electrode in dye: Place your titania coated electrode in a glass petri dish with the titania facing up Use a pipette to drop blackberry juice onto the slide until it is fully covered Cover the petri dish and leave to soak for at least 10 minutes

Organic bulk hetero-junction solar cells

Dye Sensitised Solar Cells Grätzel cell invented in 1988 Most efficient DSSC is around 11.9% Typical Si based panels on homes are around % efficient (best laboratory efficiency 25%) “Upscaling” research cells generally results in efficiency losses

“Artificial Photosynthesis” TiO 2 Conducting Glass Dye ½ I e - → 3/2 I - 3/2 I - → ½ I e - Electrolyte solution Conducting Glass

Part 2 Rinse the dye coated electrode with distilled water and then with ethanol. Leave to dry. Coat your counter electrode with carbon and wipe edges. Assemble the two glass plates with coated sides together, but offset so that uncoated glass extends beyond the sandwich. Clamp the plates together with binder clips Add a couple of drops of electrolyte solution Test your solar cell!

Discussion Our cells today, about 0.5 – 1% efficient Cheap silicon solar cells approx. 20x better per unit area Equivalent power is about 0.3 mg of coal per hour This is one of the many reasons why transitioning to renewable energy is so difficult

Discussion Why would we use TiO 2 nanoparticles and not a solid layer? Can you think of any design improvements for the cell? –Hint: what colour(s) would the dye be absorbing?

Discussion Why would we use TiO 2 nanoparticles and not a solid layer?

Discussion Why would we use TiO 2 nanoparticles and not a solid layer? –The porous TiO 2 film gives us a huge surface area to be able to coat with dye molecules, maximising the amount of light that can be absorbed Can you think of any design improvements for the cell? –Hint: how could we improve the dye?

Discussion Can you think of any design improvements for the cell? –The absorbance spectra for blackberry juice is shown below

Discussion Can you think of any design improvements for the cell? –The absorbance of blackberry juice is now overlayed with the solar emission

Discussion Why would we use TiO 2 nanoparticles and not a solid layer? –The porous TiO 2 film gives us a huge surface area to be able to coat with dye molecules, maximising the amount of light that can be absorbed Can you think of any design improvements for the cell? –By better matching the absorbance of the dye(s) used we would be able to increase the amount of visible light we are converting into electricity, resulting in much better efficiencies of the cell

Nanotechnology at Flinders Bachelor of Science (Nanotechnology) ATAR entry –Quantum Nanostructures stream SACE stage 2 chemistry, physics and mathematical studies –Biomedical Nanotechnology stream SACE stage 2 chemistry Bachelor of Science (ATAR entry 70.00) –Extended major, major or minor in physics –Extended major, major or minor in chemistry Bachelor of Science (Honours) (ATAR entry 80.00) Bachelor of Science High Achievers Program (Honours) At least three of SACE Stage 2 Biology, Chemistry, Geology, Mathematical Studies, Physics, Specialist Mathematics. ATAR entry 95.00