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 1Soaking 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

http://www.solarmer.comhttp://www.solarmer.com

Dye Sensitised Solar Cells

Grätzel cell invented in 1988

Most efficient DSSC is around 11.9%

Typical Si based panels on homes are around 15 -17% efficient (best laboratory efficiency 25%)

“Upscaling” research cells generally results in efficiency losses

“Artificial Photosynthesis”

TiO2 Con

duct

ing

Gla

ss

Dye

½ I3- + e- → 3/2 I-

3/2 I- → ½ I3- + e-

Electrolyte solution

Con

duct

ing

Gla

ss

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 TiO2 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 TiO2 nanoparticles and not a solid

layer?

Discussion• Why would we use TiO2 nanoparticles and not a solid

layer?– The porous TiO2 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 TiO2 nanoparticles and not a solid

layer?– The porous TiO2 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 70.00 – 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