Organic and Hybrid Photovoltaic
Devices for Renewable Energy
Dr. Lluis F. Marsal
Email: [email protected]
Nanophotonic and Electonic Systems
1
Research lines in OSC
Transport mechanisms and Modelling of Organic Solar Cells
Active layer morphology of BHJ organic solar cells
Hybrid solar cells based on organic polymers and inorganic nanoparticles
Nanostructured BHJ Organic Solar Cells
Projects
CONSOLIDER (CSD2007-00007), “Hybrid Optoelectronic and Photovoltaic Devices
ICT-FP7-247745, “Flexible organic and large area electronics (FOLAE) and its
exploitation”
A/016246/08 and A/024560/09, “Development of technology for nanostructured
organic solar cells”.
TEC2009-09551, “Photovoltaic solar cells and active photonic crystals based on
hybrid organic-inorganic micro-and nanostructures”
2
Nanostructured Solar Cells
Hybrid solar cells
BHJ solar cells
Low cost, Large-area, Simple fabrication (No clean room or
high T steps needed) ☺
Flexible panels (form factor) ☺
Versatility of polymer structure and property via synthesis ☺
Nanostructural tailoring ☺
Low efficiency A narrow absorption band that limits solar
spectrum wavelength absorption
Not all excitons reach at interface (the
diffusion lengths of excitons and of free
carriers are in the nanometric size)
Increasing Performance: Matching the Solar Emission
Increase absorption (1)
•
Higher absorption coefficient; Higher charge carrier mobility
Shift of the absorption to red (2)
•
Low Band Gap Polymers
Transport mechanisms and Modelling
• P3HT/Si hybrid solar cell
Journal of Applied
Physics. 107, 044505
(2010).
• Pentacene/C60 solar cell
Applied Physics
Letters 97, 013305
(2010).
• P3HT:PCBM bulk heterojunction solar cells
Transport mechanisms and Modelling
VD = φPc- φC60 = VD,C60+ VD,Pc
1
0
EF,Pc
VD,Pc
o
-1
φPc
Energy (eV)
φC60
-2
-3
VD,C60
φbM
EF,C60
-4
φbL
∆EHH
-5
-6
0,0
2,0x10
-6
4,0x10
-6
Thickness (cm)
6,0x10
-6
8,0x10
-6
Transport mechanisms and Modelling
Journal of Applied
Physics. (2011).
Submitted
Fabrication of Bulk Heterojunction Solar Cells
0
Measured illuminated I-V curves (fresh)
-1
P3HT PCBM[70]
2
Current (mA/cm )
-2
(C)
-3
-4
(B)
-5
(A)
-6
S1 Curve (A)
S2 Curve (B)
S3 Curve (C)
-7
-8
0,0
Microelectronics Reliability 51, 597 (2011).
0,1
0,2
0,3
0,4
0,5
0,6
Voltage (V)
t layer
r
o
p
s
n
a
hole tr
Advanced Functional Materials, 21, 2705 (2011).
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Active Layer Morphology
P3HT:PC[70]BM (wt%)
1:0.84
1:1
1:1.21
P3HT
PC[70]BM
The difference of morphologies affected the performance of the organic solar cell.
10
Eu3+:La2O3 nanocrystals embedded in P3HT matrix
Solar spectrum
Modifying the incoming spectrum
for down-conversion and downshifting
Eu3+:La2O3:P3HT matrix
Optical Materials 33, 1120 (2011).
Europium doped lanthanum oxide nanocrystals
Eu3+:La2O3 nanocrystals embedded inP3HT matrices
8
P3HT
P3HT+10 wt% NPs
P3HT+35 wt% NPs
P3HT+65 wt% NPs
P3HT+80 wt% NPs
6
Current (nA)
4
2
0
-2
-4
-6
-8
-4
-2
0
2
4
Bias voltage (V)
1,0
P3HT(1):PCBM(0.8)efficiency: 2,60%
3+
P3HT(1):PCBM(0.8):Eu :La2O3(0.5)efficiency: 0,91%
3+
P3HT(1):PCBM(0.8):Eu :La2O3(0.25)efficiency: 0,91%
3+
Photocurrent (mA)
0,5
P3HT(1):PCBM(0.8):Eu :La2O3(0.75)efficiency: 0,28%
0,0
-0,5
-1,0
0,0
0,2
0,4
Voc (V)
0,6
0,8
Strategies to Improve the Efficiency of Organic Solar Cells
Interdigitated vertical channelsObjective
of donor and acceptor materials of width
comparable to the exciton diffusion length.
Reflecting
electrode
IDEAL ORDERED
BULK HJ SOLAR CELL
Electron
accepting
semiconductor
(e.g. PCBM )
~ absorption lengths
(200 - 300 nm)
1st semiconductor
(e.g. P3HT)
Transparent
electrode
(e.g. ITO)
<
exciton diffusion lengths (~20-60 nm)
Nanostructured Organic Solar Cells
Self-ordered
nanoporous alumina
14
14
Nanostructured Organic Solar Cells
Geometry characterization of the P3HT nanopillars manufactured in the
NEPHOS’s Laboratory.
Solar Energy Materials and Solar Cells 94, 1247 (2010)
15
15
Nanostructured Organic Solar Cells
P3HT Nanopillars using templated of anodization alumina and manufactured with
phosphoric acid (H3PO4). ESEM Characterization.
PEDOT:PSS
ITO
Glass
Cross section
Cross section with all layers
(Glass/ITO/PEDOT:PSS/P3HT Nanopillars)
16
Flexible Organic Solar Cells
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