JESSICA CO-REYES
WASHINGTON UNIVERSITY IN ST. LOUIS,
CLASS OF 2014
CHEMICAL ENGINEERING
UNICAMP, BRAZIL
JUNE 5, 2012
PLANTS AND PANELS:
BIOHYBRID PHOTOVOLTAIC CELLS
overview
• solar energy
• problems
• one solution
• future
0.039%
*
why is it so difficult to harvest
the sun’s energy?
* “Clean Energy Progress Report.” International Energy Agency, 2011.
e
absorb
energy
separate
charge
15%
silicon solar cells
$$$
dyesensitized
solar
cells
11%
*
* Han, L., Dye-Sensitized Solar
Cells with Conversion
Efficiency of 11.1%, 2006.
45(25): L638-L640.
http://www.energyer.com/Know_How/dye-sensitizedsolar-cell.html
problems
low
absorption
excitation transfer
incompatibility
low
absorption
______________
absorption spectrum
co-sensitization
(Arakawa et. al, The Royal Society of Chemistry, 2012)
excitation transfer
incompatibility
____________
Förster Resonance Energy Transfer (FRET)*
* Basham, J. (2010). "Forster Resonance Energy Transfer in Dye-Sensitized Solar Cells." ACS Nano 4(3):
1253-1258.
nature as
inspiration:
- pigments
- reaction
center
pigment:
BChl
c
______
chlorosomes
green photosynthetic bacteria- Chloroflexus aurantiacus
bacteriochlorophyll c (BChl c)
BChl c
oligomers
Base plate
(Psencik et al., J. Bacteriology 2009)
Cryo-EM Projection
images
Reaction
Center
Cytochrome c
Complex et al., Energy, Environ. Sci.
(Modesto-Lopez
2010)
artificial reaction center:
PbS
quantum dots
__________________
SILAR- successive ionic layer adsorption and reaction
0.02 M
Pb(NO3) 2
in MeOH
MeOH
0.02 M
Na2S
in MeOH
MeOH
biohybrid solar cells
Solar energy harvesting
& funneling
Artificial reaction center: PbS
n-type: columnar TiO2
ITO substrate
-
+
-
Pt coated ITO glass
Electrolyte: NaS and Na2SO3
Antenna system: Chlorosome
Neutralized by
electrolyte
Charge separation
future?
• possibilities
• spray onto roofs
• biohybrid water-splitting systems
• challenges
• long-term stability
• scaling-up
context of biofuels
• energy problem
• promising but young technology
• tension
questions?