LIOS
Inorganic Nanoparticles:
From colloids to photovoltaic devices
E Arici1* , J.
E.
J N.
N Feritas2, N.
N S.
S Sarıciftci1, A.F.
A F Nogueiria2
1Linz
Institute for Organic Solar Cells
JKU, Linz
2Chemıstry Depatment Unıversıty of Campına Brazil
Overview
• Synthesis principles of inorganic QDs
• Organic-inorganic hybrid solar cells
– CdSe QDs as electron acceptor
– CuInS2 QDs as electron donor
LIOS
What are Quantum Dots (QDs)?
Photostability
Compatibility with diverse matrices
Broad Absorbance Range
g
High : 106 M/cm3
OPVs
Tunable Colors via QD size
Single Excitation Source
EQE: 12-60%
QLEDs
Diagnostic Marker
LIOS
Quantum Confinement
LIOS
Absorption
p
of CdSe QDs
LIOS
Increasing size of the QDs leads to lower band gap & higher extinction coefficient
Synthesis:Hot Injection
LIOS
Role of the surfactant
LIOS
(TOPO)
(HPA)
Shape control
Anisotropic growth of CdSe QDs
Faster growth
in c axis!
Main reason:
CdSe in wurtzide structure
- Different number of
dangling bonds at 001 face
only TOPO
TOPO/HPA:
85/15
LIOS
Synthetic controll of the
anisotropic growth
- High monomer concentration
- Face selective surfactants
TOPO/HPA:
80/20
Overview
• Introduction to inorganic QDs
• CdSe QDs as electron acceptor
in bulk heterojunction solar cells
• CuInSe2 QDs as electron donor
in bulk heterojunction solar cells
LIOS
First CdSe/polymer hybrid solar cells
LIOS
Device structure
P3HT
P3HT
CdSe
(TOPO/HPA)
W.U. Huynh, J.J. Dittmer, A.P. Alivisatos
Science, 295 (2002) 2425
Hybrid concept
LIOS
in bulk heterojunction devices
Effective charge separation
High interface by fabricating blends
Effective charge transport
Percolation of each component
in the interpenetrating network
Electron donor
Electron acceptors
PCBM
CdSe
[2 nm-4 nm]
First Tests
HR-TEM image of
TOPO capped CdSe
LIOS
Photovoltaic activity
Absorbance
Curren
nt [mA/cm
m2]
20 wt
wt.%
% PFT
Voltage [V]
PVT/PCBM/CdSe blends
Variation of CdSe/PCBM ratio
in 20 wt.% PFT
LIOS
Energy scheme of the device
PCBM/CdSe
0:1
0.3:0.7
1:0
0703
0.7:0.3
1:1
- Increase of photo current and open circuit voltage using CdSe QDs in organic
bulk heterojunction solar cells
Morphology studies
AFM images of PVT blends
PCBM/CdSe:0.7/0.3
PCBM/CdSe:0/1
PCBM/CdSe:1/1
PCBM/CdSe:0.3/0.7
Phase separation by increasing CdSe ratio in the blend
LIOS
IPCE depending on the size of CdSe QDs
in PFT/PCBM blends
LIOS
PCBM/CdSe:1:1
in 20 wt.% PFT
4 nm
3 nm
2 nm
Increasing the QD size leads to an increase of the photo current
LIOS
• Introduction to inorganic QDs
• CdSe QDs as electron acceptor
in bulk heterojunction solar cells
• CuInSe2 QDs as electron donor
in bulk heterojunction solar cells
Synthesis of CIS/TPP
HR TEM
HR-TEM
CIS
O
P
LIOS
O
O
CIS/TPP
5 nm
“Synthesis and characterization of nanocrystalline CuInSx for applications in organic/inorganic
hybrid solar cells” E. Arici*, N. S. Sariciftci, D. Meissner, Molecular Crystals Liquid Crystals, Vol.
383, pp 129-136 (2002).
Materials and Device Structure
CIS
O
P
O
O
CIS/TPP
PCBM
O
O
O
O
S
S
S
S
n
+
O
O
O
O
*
O
n
SO3-
*
*
S
O
n
*
SO3H
PEDOT:PSS
Poly(3,4-ethylene-dioxythiophene)
/poly(styrenesulfonate)
CuInS2 acts as electron donor/ PCBM as electron acceptor
LIOS
Thin film preparation
LIOS
AFM
from acetonitrile
50-90 nm
from Pedot:PSS (6:1)
Agglomerate size
70-120 nm
Phase seperation in thin layers(~100 nm) spin cast from PEDOT:PSS/CuInS2
dispersions leads to an increase of the agglomerate size.
CIS Hybrid Solar Cells
• Light harvesting in the range of 350-950 nm
•~ Maximum IPCE of 20 %
g the device configuration:
g
ITO/CIS+PEDOT:PSS/PCBM/LiF/Al
using
“Hybrid solar based on nanoparticles of CuInS2 in organic matrices”
E. Arici*, N. S. Sariciftci, D. Meissner, Adv. Funct. Mater., 13, 2, 165-171 (2003).
LIOS
Conclusions
•Photovoltaic activity of solution processable CdSe
and CuInS2 monolayers
•The
The prove of the concept using CdSe and CuInS2
nanoparticles in hybrid solar cells for enhanced
light harvesting
LIOS
Acknowledgements
I thank to all the collegues in LIOS
LIOS, who supported
my work in many ways!
LIOS members:
A. Mammatimin, D. Egbe, A. Workneh,
A Montaigne P Thomyonkit,
A.Montaigne,P.
Thomyonkit M.
M White,
White A.
A Pivrikas,
Pivrikas
P. Stadler, M. Bednorz,J. Gasiowski, E. Mujenovic,
K. Oppelt,M. Kruijen,A. Fuchsbauer,M. Egginger, D. Hoeglinger, G.
K l b M
Kalab,
M. Li
Lipp, H
H. N
Neugebauer,
b
N
N. S
S. Sariciftci
S i ift i
Currently founded by
Ministery of Education and Research, Elise Richter Programm,
Austria.
j
Nm. AE 3486 123
FWF Project
LIOS