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Adding Interstitial Layers For Improved Open-Circuit Voltage in Organic Solar Cells . Husna Anwar ’15 Arango Lab Leap Symposium 2013. SUNNY WITH A CHANCE OF POWER:. What’s the big deal?. CO2 levels are at 400 parts per million (ppm) in the atmosphere – . What’s the big deal?. - PowerPoint PPT Presentation
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Adding Interstitial Layers For Improved Open-Circuit
Voltage in Organic Solar Cells
SUNNY WITH A CHANCE OF POWER:
Husna Anwar ’15Arango Lab
Leap Symposium 2013
What’s the big deal?•CO2 levels are at 400 parts per million
(ppm) in the atmosphere –
What’s the big deal?•- at 450 ppm temperatures will rise by 2
°C
What’s the big deal?•Fossil Fuels are a finite resource
What’s the big deal?•Fossil Fuels are a finite resource
Image: National Geographic
Alberta Tar Sands
Why Organic Photovoltaics (PV)Silicon-based panels are bulky, expensive and difficult to produce and install.
Image: Birmingham MailImage: Birmingham Mail
Why Organic Photovoltaics (PV)Silicon-based panels are bulky, expensive and difficult to produce and install.
Organic PV is light-weight, flexible and can be produced in a matter of hours. Image:SoloPower
Image: Birmingham Mail
Image: SoloPower
Image: Birmingham Mail
Image: SoloPower
Why Organic Photovoltaics (PV)
Image: Global Solar
Why Organic Photovoltaics (PV)
Image: Global Solar
Image: Global Solar
Image: Global Solar
Image: Global Solar
Why Organic Photovoltaics (PV)
Image: Global Solar
Image: Global Solar
Image: Global Solar
Image: Global Solar
Image: Global Solar
The Donor/Acceptor Concept
Image: Phoebe Tengdin
Donor Acceptor
The Donor/Acceptor Concept
Image: Phoebe Tengdin
Donor
Acceptor
The Donor/Acceptor Concept
Image: Phoebe Tengdin
1
Photocurrent generation
Electrons
Holes
Voltage and Current•Current is the flow of charge
Voltage and Current•Current is the flow of charge•Voltage is what drives charge to flow
Voltage and Current•Current is the flow of charge•Voltage is what drives charge to flow•Power depends on
both current and voltage
P=IV
Issues with Organic PV•Low efficiency due to low open-circuit
voltage (Voc)
Issues with Organic Solar•Low efficiency due to low open-circuit
voltage (Voc)•Voc is connected to interfacial bandgap
Issues with Organic Solar•Low efficiency due to low open-circuit
voltage (Voc)•Voc is connected to interfacial bandgap
-3.0 eV
-4.9 eV
VOC depends on interfacial bandgap
LUMO
HOMO
P3HT
PCBM
-4.0 eV
-6.5 eV
Deposition methods•Spin-coating
A B C D
Image: Andrea Miranda
Substrate
Materialdropped
Spinning
Deposition methods•Vapor Deposition
A B C
Substrate
MaterialThermal
Evaporator(under
vacuum)
Material evaporates
Coated substrate
Image: Sophia Weeks
Deposition methods•Transfer Printing
PDMS
PCBM
Glass
PEDOT:PSSP3HT
PCBM spin-coated
A B C D
ITO
What we did•Vapor deposition of small molecule with a
wide bandgap
LUMO
HOMO
P3HT
PCBM
Charge recombination
at the interface
What we did•Vapor deposition of small molecule with a
wide bandgap-3.0 eV
-4.9 eV
-3.1 eV
-4.0 eV
-5.7 eV -6.5 eV
LUMO
HOMO
P3HTAlq3
PCBM
very thin interstitial layer of Alq3
Results
dark
light
Results
Voc =0.27 V
Jsc =0.013 mA
Results
Voc =0.44 V
Voc =0.27 V
Jsc =-0.011 mA
Jsc =0.013 mA
Issues•Very low short-circuit current (Jsc)
Issues•Very low short-circuit current (Jsc)•Inconsistent device performance
Issues•Very low short-circuit current (Jsc)•Inconsistent device performance
PCBM film on a PDMS stamp
Issues•Very low short-circuit current (Jsc)•Inconsistent device performance
Surface topography imaged through Atomic Force Microscopy (AFM)
PCBM film on a PDMS stamp
-29 nm
68 nm
5 nm
5 nm
10 nm
0 nm0 nm
What we found out•Alternative energy is essential
What we found out•Alternative energy is essential•Organic PV is a very viable solution
What we found out•Alternative energy is essential•Organic PV is a very viable solution•Adding a small molecule almost doubled
our Voc
What we found out•Alternative energy is essential•Organic PV is a very viable solution•Adding a small molecule almost doubled
our Voc
•We need better Jsc and consistency
What we found out•Alternative energy is essential•Organic PV is a very viable solution •Adding a small molecule
almost doubled our Voc
•We need better Jsc and consistency
•We all want this jacket for when our phones die:
Image: Crunch Wear
Future Work•Vapor deposition of C60 instead of PCBM
for consistency-3.0 eV
-4.9 eV
-3.1 eV
-4.5 eV
-5.7 eV
LUMO
HOMO
P3HTAlq3
C60
-6.2 eV
Buckministerfullerene (C60) can be vapor deposited for uniform films
The people who made this summer awesome…• Professor Alexi Arango,
Kanchi Gashaw and Ednah Louie
• Sarah Byrne, Len and Thomas
• Mount Holyoke College
Image: Alexi Arango
