Oxidation of silver top electrodes in polymer solar cells induces the devices to exhibit a transition from conventional to inverted photovoltaic characteristics. As silver oxidizes, its work function increases from 4.3 to 5.0 eV. The silver top electrode thus reverts from collecting electrons to collecting holes during device operation. We have quantified the extent of this transformation and find it to be correlated with the rate of silver oxidation, which we can influence by altering the annealing sequence of the polymer photoactive layer, ultimately varying the grain size of silver in the top electrode.

1.
C. S.
Kim
,
S. S.
Lee
,
E. D.
Gomez
,
J. B.
Kim
, and
Y. -L.
Loo
,
Appl. Phys. Lett.
94
,
113302
(
2009
).
2.
S. K.
Hau
,
H. L.
Yip
,
N. S.
Baek
,
J.
Zou
,
K.
O’Malley
, and
A. K. Y.
Jen
,
Appl. Phys. Lett.
92
,
253301
(
2008
).
3.
C. S.
Kim
,
L. L.
Tinker
,
B. F.
Disalle
,
E. D.
Gomez
,
S. S.
Lee
,
S.
Bernhard
, and
Y. -L.
Loo
,
Adv. Mater.
21
,
3110
(
2009
).
4.
S. K.
Hau
,
H. L.
Yip
,
O.
Acton
,
N. S.
Baek
,
H.
Ma
, and
A. K. Y.
Jen
,
J. Mater. Chem.
18
,
5113
(
2008
).
5.
C.
Waldauf
,
M.
Morana
,
P.
Denk
,
P.
Schilinsky
,
K.
Coakley
,
S. A.
Choulis
, and
C. J.
Brabec
,
Appl. Phys. Lett.
89
,
233517
(
2006
).
6.
A. K. K.
Kyaw
,
X. W.
Sun
,
C. Y.
Jiang
,
G. Q.
Lo
,
D. W.
Zhao
, and
D. L.
Kwong
,
Appl. Phys. Lett.
93
,
221107
(
2008
).
7.
J.
Kim
,
D. Y.
Khang
,
J. H.
Kim
, and
H. H.
Lee
,
Appl. Phys. Lett.
92
,
133307
(
2008
).
8.
D. R.
Lide
,
CRC Handbook of Chemistry and Physics
(
CRC
,
Cleveland
,
1990
).
9.
H. W.
Choi
,
S. Y.
Kim
,
K. B.
Kim
,
Y. H.
Tak
, and
J. L.
Lee
,
Appl. Phys. Lett.
86
,
012104
(
2005
).
10.
C. S.
Kim
,
S. S.
Lee
,
L.
Tinker
,
S.
Bernhard
, and
Y. -L.
Loo
,
Chem. Mater.
21
,
4583
(
2009
).
11.
J. Y.
Kim
,
S. H.
Kim
,
H. H.
Lee
,
K.
Lee
,
W.
Ma
,
X.
Gong
, and
A. J.
Heeger
,
Adv. Mater.
18
,
572
(
2006
).
12.
J. Y.
Kim
,
K.
Lee
,
N. E.
Coated
,
D.
Moses
,
T. Q.
Nguyen
,
M.
Dante
, and
A. J.
Heeger
,
Science
317
,
222
(
2007
).
13.
C. S.
Kim
,
J. B.
Kim
,
S.
Lee
,
Y. S.
Kim
, and
Y. -L.
Loo
, “
Sequence of annealing polymer photoactive layer influences the air stability of inverted solar cells
,”
Org. Electron.
(to be published), doi:10.1016/j.orgel.2009.08.013.
14.
X.
Yang
,
J.
Loos
,
S. C.
Veenstra
,
W. J. H.
Verhees
,
M. M.
Wienk
,
J. M.
Kroon
,
M. A. J.
Michels
, and
R. A. J.
Janssen
,
Nano Lett.
5
,
579
(
2005
).
15.
G.
Li
,
V.
Shrotriya
,
J.
Huang
,
Y.
Yao
,
T.
Moriarty
,
K.
Emery
, and
Y.
Yang
,
Nature Mater.
4
,
864
(
2005
).
16.
M.
Ohring
,
The Materials Science of Thin Films
(
Academic
,
Boston
,
1992
).
17.
R. E.
Hoffman
and
D.
Turnbull
,
J. Appl. Phys.
22
,
634
(
1951
).
You do not currently have access to this content.